CFEngine is a suite of programs for integrated autonomic management of either individual or networked computers. It has existed as as software suite since 1993 and this version published under the GNU Public License (GPL v3) and a Commercial Open Source License (COSL). CFEngine is Copyright by CFEngine AS, a company founded by CFEngine author Mark Burgess.
This document describes version 3 of CFEngine, which is a radical departure from earlier versions. It is both simpler and more powerful. CFEngine 3 will exist in four versions, each of which adds to the following
This document is valid for all versions of CFEngine. Whenever a feature is only available in a specific version, that fact will be noted in the documentation for that feature (if there is no note, then that feature is available in all versions).
CFEngine 3 has been changed to be both a more powerful tool and a much simpler tool. CFEngine 3's language interface is not backwards compatible with the CFEngine 2 configuration language, but it interoperates with CFEngine 2 so that it is "run-time compatible". This means that you can change over to version 3 slowly, with low risk and at your own speed.
With CFEngine 3 you can install, configure and maintain computers using powerful hands-free tools. You can also integrate knowledge management and diagnosis into the processes.
CFEngine differs from most management systems in being
CFEngine 3 consists of a number of components. The names of the programs are intentionally different from those in CFEngine 2 to help disambiguate them (and some CFEngine 2 components have been merged and/or eliminated). The starred components are new to CFEngine 3:
Active agent – responsible for maintaining promises about the state of
your system (in CFEngine 2 the agent was called cfagent).
You can run cf-agent manually, but if you want to have it
run on a regular basis, you should use cf-agent
(instead of using cron).
cf-agent keeps the promises made in common
and agent bundles, and is affected by
common and agent
control bodies.
Scheduler – responsible for running cf-agent on a regular (and
user-configurable) basis (in CFEngine 2 the scheduler was called
cfexecd).
EXECUTOR
cf-execd keeps the promises made in common
bundles, and is affected by
common and executor
control bodies.
Knowledge modelling agent – responsible for building and analysing a semantic knowledge network.
cf-know keeps the promises made in common
and knowledge bundles, and is affected by
common and knowledge
control bodies.
Passive monitoring agent – responsible for collecting information about
the status of your system (which can be reported upon or used to
enforce promises or influence when promises are enforced). In CFEngine 2
the passive monitoring agent was known as cfenvd.
cf-monitord keeps the promises made in common
and monitor bundles, and is affected by
common and monitor
control bodies.
Promise validator – used to verify that the promises used by the other
components of cfengine are syntactically valid.
cf-promises does not execute any promises, but is can syntax-check
all of them.
Remote run agent – used to execute cf-agent on a remote machine (in
CFEngine 2 the remote run agent was called cfrun).
cf-runagent does not keep any promises, but instead is used to ask
another machine to do so.
Server – used to distribute policy and/or data files to clients requesting
them and used to respond to requests from cf-runagent (in
CFEngine 2 the remote run agent was called cfservd).
cf-serverd keeps the promises made in common
and server bundles, and is affected by
common and server
control bodies.
Self-knowledge extractor – takes data stored in cfengine's embedded databases and converts them to human readable form
cf-report keeps the promises made in common
bundles, and is affected by
common and reporter
control bodies.
Key generation tool – run once on every host to create public/private key
pairs for secure communication (in CFEngine 2 the key generation tool
was called cfkey). cf-key does not keep any promises.
A data aggregator used as part of the commercial product. This stub is not used in the community edition of CFEngine.
Unlike previous versions of cfengine, which had no consistent model For its features, you can recognize everything in CFEngine 3 from just a few concepts.
If you have used cfengine before then the most visible part of cfengine 3 will be its new language interface. Although it has been clear for a long time that the organically grown language used in cfengine 1 and 2 developed many problems, it was not immediately clear exactly what would be better. It has taken years of research to simplify the successful features of cfengine to a single overarching model. To understand the new cfengine, it is best to set aside any preconceptions about what cfengine is today. CFEngine 3 is a genuine "next generation" effort, which will be a springboard into the future of system management.
CFEngine 3 is a significant rewrite of underlying cfengine technology which preserves the core principles and methodology of cfengine's tried and tested approach. It comes with a new, improved language, with a consistent syntax and powerful pattern expression features that display the intent behind cfengine code more clearly. The main goal in changing the language is to simplify and improve the robustness and functionality without sacrificing the basic freedoms and self-repairing concepts.
CFEngine 3's new language is a direct implementation of a model developed at Oslo University College over the past four years, known colloquially as "Promise Theory". Promises were originally introduced by Mark Burgess as a way to talk about cfengine's model of autonomy and have since become a powerful way of modelling cooperative systems – not just computers, but humans too.
“The biggest challenge of implementing cfengine in our organization
was not technical but political – getting everyone to agree.
Promise theory was a big help in understand this.”
CFEngine 3 is a generic implementation of the language of promises that allows all of the aspects of configuration and change management to be unified under a single umbrella.
Why talk about promises instead of simply talking about changes? After all, the trend in business and IT management today is to talk about Change Management (with capital letters), e.g. in the IT Infrastructure Library (ITIL) terminology. This comes from a long history of process management thinking. But we are not really interested in change – we are interested in avoiding it, i.e. being in a state where we don't need to make any changes. In other words we want to be able to promise that the system is correct, verify this and only make changes if our promises are not kept. If you want to think ITIL, think of this as a service that cfengine provides.
To put it another way, cfengine is not really a change management system, it is a maintenance system. Maintenance is the process of making small changes or corrections to a model. A `model' is just another word for a template or a specification of how we want the system to work. CFEngine's model is based on the idea of promises, which means that it focuses on what is stable and lasting about a system – not about what is changing.
This is an important philosophical shift. It means we are focused mainly on what is right and not on what is wrong. By saying what "right" is (the ideal state of our system) we are focused on the actual behaviour. If we focus too much on the changes, i.e. the differences between now and the future, we might forget to verify that what we assume is working now in fact works.
Models that talk about change management tend to forget that after every change there is a litany of incidents during which it is necessary to repair the system or return it to its intended state. But if we know what we have promised, it is easy to verify whether the promise is kept. This means that it is the promises about how the system should be that are most important, not the actual changes that are made in order to keep them.
In order to install cfengine, you should first ensure that the following packages are installed.
Additional functionality becomes available if other libraries are present, e.g. OpenLDAP, client libraries for MySQL and PostgreSQL, etc. It is possible to run cfengine without these, but related functionality will be missing.
Unless you have purchased ready-to-run binaries, or are using a
package distribution, you will need to compile cfengine. For this you
will also need a build environment tools: gcc, flex, bison.
The preferred method of installation is then
tar zxf cfengine-x.x.x.tar.gz
cd cfengine-x.x.x
./configure
make
make install
This results in binaries being installed in /usr/local/sbin. Since this is not necessarily a local file system on all hosts, users are encouraged to keep local copies of the binaries on each host, inside the cfengine trusted work directory.
The CFEngine 3 language has a few simple rules:
bundle agent-type identifier
{
...
}
body constraint_type template_identifier
{
...
}
matching and expanding on a reference inside a promise of the form ‘constraint_type => template_identifier’.
cfengine_word => user_defined_template(parameters)
user_defined_template
builtin_function()
"quoted literal scalar"
{ list }
In each of these cases, the right hand side is a user choice.
In order to achieve the desired simplifications, it was decided to reserve a private work area for the cfengine tool-set.
| In cfengine 1.x, the administrator could choose the locations of configuration files, locks, and logging data independently. In cfengine 2.x, this diversity has been simplified to a single directory which defaults to /var/cfengine (similar to /var/cron), and in cfengine 3.x this is preserved. |
/var/cfengine
/var/cfengine/bin
/var/cfengine/inputs
/var/cfengine/outputs
The installation location /usr/local/sbin is not necessarily a local file system, and cannot therefore be trusted to a) be present, and b) be authentic on an arbitrary system.
Similarly, a trusted cache of the input files must now be maintained in the inputs subdirectory. When cfengine is invoked by the scheduler, it reads only from this directory. It is up to the user to keep this cache updated, on each host. This simplifies and consolidates the cfengine resources in a single place.
Unlike cfengine 2, cfengine 3 does not recognize the
CFINPUTS environment variable.
The outputs directory is now a record of spooled run-reports. These
are often mailed to the administrator by cf-execd, or can be copied
to another central location and viewed in an alternative browser.
CFEngine runs on every computer individually and each time it wakes up the underlying generic agent platform discovers and classifies properties of the environment or context in which it runs. This information is cached and may be used to make decisions about configuration1.
Classes fall into hard (discovered) and soft (defined) types. A single class can be one of several things:
ultrix, sun4, etc.
www). If your
system returns a fully qualified domain name for your host (e.g.,
www.iu.hio.no), cfengine will also define a hard class for the fully
qualified name, as well as the partially-qualified component names
iu.hio.no, hio.no, and no.
Monday, Tuesday, Wednesday, ..).
Hr00,
Hr01 ... Hr23).
GMT_Hr00, GMT_Hr01 ... GMT_Hr23).
This is consistent the world over, in case you need virtual simulteneity of change
coordination.
Min00, Min17 ... Min45).
Min00_05, Min05_10 ... Min55_00).
Q1, Q2,
Q3, Q4).
Hr12_Q3).
Day1, Day2, ... Day31).
January, February, ... December).
Yr1997, Yr2004).
Night,Morning,Afternoon,Evening, which fall into six hour blocks
starting at 00:00 hours.
Lcycle_0, Lcycle_1, Lcycle_2, used in long term resource memory).
-D command
line option, or defined in a classes promise or body,
restart_class in a processes promise, etc).
ipv4_192_0_0_1,
ipv4_192_0_0, ipv4_192_0, ipv4_192).
net_iface_xl0,
net_iface_vr0).
cf-monitord.
zone_global,
zone_foo, zone_baz).
To see all of the classes defined on a particular host, run
host# cf-promises -v
as a privileged user. Note that some of the classes are set only
if a trusted link can be established with cfenvd, i.e. if both
are running with privilege, and the /var/cfengine/state/env_data
file is secure. More information about classes can be found in connection with
allclasses.
Classes are defined in bundles. Bundles of type common yield classes that
are global in scope, whereas in all other bundle types classes are local.
Classes are evaluated when the bundle is evaluated (and the bundles are
evaluated in the order specified in the bundlesequence).
Consider the following example.
body common control
{
bundlesequence => { "g","tryclasses_1", "tryclasses_2" };
}
#################################
bundle common g
{
classes:
"one" expression => "any";
}
#################################
bundle agent tryclasses_1
{
classes:
"two" expression => "any";
}
#################################
bundle agent tryclasses_2
{
classes:
"three" expression => "any";
reports:
one.three.!two::
"Success";
}
Here we see that class ‘one’ is global (because it is defined inside the
common bundle), while classes ‘two’ and ‘three’ are local (to
their respective bundles).
The report result `Success' is therefore true because only ‘one’ and
‘three’ are in scope (and ‘two’ is not in scope) inside of the
third bundle.
Filenames in Unix-like operating systems use the forward slash ‘/’ character for their directory separator . All references to file locations must be absolute pathnames in cfengine, i.e. they must begin with a complete specification of which directory they are in. For example:
/etc/passwd
/usr/local/masterfiles/distfile
The only place where it makes sense to refer to a file without a complete directory specification is when searching through directories for different kinds of file, e.g. in pattern matching
leaf_name => { "tmp_.*", "output_file", "core" };
Here, one can write core without a path, because one is looking for any file of that name in a number of directories.
The Windows operating systems traditionally use a different filename convention. The following are all valid absolute file names under Windows:
c:\winnt
"c:\spaced name"
c:/winnt
/var/cfengine/inputs
//fileserver/share2/dir
The `drive' name “C:” in Windows refers to a partition or device. Unlike Unix, Windows does not integrate these seamlessly into a single file-tree. This is not a valid absolute filename:
\var\cfengine\inputs
Paths beginning with a backslash are assumed to be win32 paths. They must begin with a drive letter or double-slash server name.
Note in recent versions of Cygwin you can decide to use the
/cygdrive to specify a path to windows file E.g
/cygdrive/c/myfile means c:\myfile or you can do it straight away in
cfengine as c:\myfile.
CFEngine 3 has a completely new syntax, designed to solve the issues brought up from 15 years of experience with configuration management. Rather than clutter cfengine 3 with buggy backward-compatability issues, it was decided to make no compromises with cfengine 3 and instead allow cfengine 2 and cfengine 3 to coincide in a cooperative fashion for the foreseeable future. This means that users can upgrade at their own pace, in the classic cfengine incremental fashion. We expect that cfengine 2 installations will be around for years to come so this upgrade path seems the most defensible.
The daemons and support services are fully interoperable between
cfengine 2 and cfengine 3, so it does not matter whether you run
cfservd (cf2) together with cf-agent (cf3) or
cf-serverd (cf3) together with cfagent (cf2). You can
change the servers at your own pace.
CFEngine 3's cf-execd replaces cfengine 2's cfexecd and
it is designed to work optimally with cf-agent (cf3). Running
this daemon has no consequences for access control, only for
scheduling cf-agent. You can (indeed should) replace
cfexecd with cf-execd immediately. You will want to
alter your crontab file to run the new component instead of the
old. The sample cfengine 3 input files asks cf-agent to do
this automatically, simply replacing the string.
The sample inputs files supplied with cfengine 3 contain
promises to integrate cfengine 2 as described. What can you do to
upgrade? Here is a simple recipe that assumes you have a standardized
cfengine 2 setup, running cfexecd in crontabs and possibly
running cfservd and cfenvd as daemons.
cfexecd or cfagent to crontabs etc. CFEngine 3
will handle this from now on and encapsulate old cfengine 2 scripts.
cd your-path/inputs.
cf-agent --bootstrap as the root or privileged user. This will install
cfengine 3 in place of cfengine 2, integrate your old cfengine 2
configuration, and warn you about any rules that need to be removed
from your old cfengine configuration.
cfservd and replace them with rules to run
cf-serverd at your own pace.
One of the practical advantages of cfengine is that you can test it without the need for root or administrator privileges. This is recommended for all new users of cfengine 3.
CFEngine operates with the notion of a work-directory. The default
work directory for the root user is /var/cfengine
(except on Debian Linux and various derivatives which prefer
/var/lib/cfengine). For any other user, the work directory
lies in the user's home directory, named ~/.cfagent. CFEngine
prefers you to keep certain files here. You should not resist this
too strongly or you will make unnecessary trouble for yourself. The
decision to have this `known directory' was made to simplify a lot of
configuration.
To test cfengine as an ordinary user, do the following:
host$ mkdir -p ~/.cfagent/inputs
host$ mkdir -p ~/.cfagent/bin
host$ cd src
host$ cp cf-* ~/.cfagent/bin
host$ cd ../inputs
host$ cp *.cf ~/.cfagent/inputs
You can test the software and play with configuration files by editing the basic get-started files directly in the ~/.cfagent/inputs directory. For example, try the following:
host$ ~/.cfagent/bin/cf-promises
host$ ~/.cfagent/bin/cf-promises --verbose
This is always the way to start checking a configuration in cfengine 3. If a configuration does not pass this check/test, you will not be allowed to use it, and cf-agent will look for the file failsafe.cf.
Notice that the cfengine 3 binaries have slightly different names than the cfengine 2 binaries. They all start with the cf- prefix.
host$ ~/.cfagent/bin/cf-agent
Here is the simplest `Hello world' program in cfengine 3:
body common control
{
bundlesequence => { "test" };
}
bundle agent test
{
reports:
Yr2009::
"Hello world";
}
If you try to process this using the cf-promises command, you will
see something like this:
atlas$ ~/LapTop/Cfengine3/trunk/src/cf-promises -r -f ./unit_null_config.cf
Summarizing promises as text to ./unit_null_config.cf.txt
Summarizing promises as html to ./unit_null_config.cf.html
The ‘-r’ option produces a report. Examine the files produced:
cat ./unit_null_config.cf.txt
firefox ./unit_null_config.cf.html
You will see a summary of how cfengine interprets the files, either in HTML or text. By default, the cfengine components also dump a debugging file, e.g. promise_output_agent.html, promise_output_agent.txt with an expanded view.
To familiarize yourself with cfengine 3, type or paste in the following example text:
########################################################
#
# Simple test execution
#
########################################################
body common control
{
bundlesequence => { "testbundle" };
}
########################################################
bundle agent testbundle
{
vars:
"size" int => "46k";
"rand" int => randomint("33","$(size)");
commands:
"/bin/echo"
args => "Hello world - $(size)/$(rand)",
contain => standard,
classes => cdefine("followup","alert");
followup::
"/bin/ls"
contain => standard;
reports:
alert::
"What happened?";
}
######################################################################
body contain standard
{
exec_owner => "mark";
useshell => "true";
}
######################################################################
body classes cdefine(class,alert)
{
promise_repaired => { "$(class)" };
repair_failed => { "$(alert)" };
}
This example shows all of the main features of cfengine: bundles, bodies, control, variables, and promises. To the casual eye it might look complex, but that is because it is explicit about all of the details. Fortunately it is easy to hide many of these details to make the example simpler without sacrificing any functionality.
The first thing to try with this example is to verify it – did we
make any mistakes? Are there any inconsistencies? To do this we use
the new cfengine program cf-promises. Let's assume that you
typed this into a file called test.cf in the current directory.
cf-promises -f ./test.cf
If all is well, typing this command shows no output. Try now running the command with verbose output.
cf-promises -f ./test.cf -v
Now you see a lot of information
Reference time set to Sat Aug 2 11:26:06 2008
cf3 CFEngine - 3.0.0
Free Software Foundation 1994-
Donated by Mark Burgess, Oslo University College, Norway
cf3 ------------------------------------------------------------------------
cf3 Host name is: atlas
cf3 Operating System Type is linux
cf3 Operating System Release is 2.6.22.18-0.2-default
cf3 Architecture = x86_64
cf3 Using internal soft-class linux for host linux
cf3 The time is now Sat Aug 2 11:26:06 2008
cf3 ------------------------------------------------------------------------
cf3 Additional hard class defined as: 64_bit
cf3 Additional hard class defined as: linux_2_6_22_18_0_2_default
cf3 Additional hard class defined as: linux_x86_64
cf3 Additional hard class defined as: linux_x86_64_2_6_22_18_0_2_default
cf3 GNU autoconf class from compile time: compiled_on_linux_gnu
cf3 Interface 1: lo
cf3 Trying to locate my IPv6 address
cf3 Looking for environment from cfenvd...
cf3 Unable to detect environment from cfMonitord
---------------------------------------------------------------------
Loading persistent classes
---------------------------------------------------------------------
---------------------------------------------------------------------
Loaded persistent memory
---------------------------------------------------------------------
cf3 > Parsing file ./test.cf
---------------------------------------------------------------------
Agent's basic classified context
---------------------------------------------------------------------
Defined Classes = ( any Saturday Hr11 Min26 Min25_30 Q2 Hr11_Q2 Day2
August Yr2008 linux atlas 64_bit linux_2_6_22_18_0_2_default x86_64
linux_x86_64 linux_x86_64_2_6_22_18_0_2_default
linux_x86_64_2_6_22_18_0_2_default__1_SMP_2008_06_09_13_53_20__0200
compiled_on_linux_gnu net_iface_lo )
Negated Classes = ( )
Installable classes = ( )
cf3 Wrote expansion summary to promise_output_common.html
cf3 Inputs are valid
The last two lines of this are of interest. Each time a component of
cfengine 3 parses a number of promises, it summarizes the information
in an HTML file called generically promise_output_component-type.html.
In this case the cf-promises command represents all possible promises,
by the type "common". You can view this output file in a suitable web browser
to see exactly what cfengine has understood by the configuration.
Now that you have verified it, you can execute it. To run this example you need to change the username `mark' to your own, or obtain root privileges to change to another user. The non-verbose output of the script when run in the cfengine 3 directory looks something like this:
host$ ./cf-agent -f ../tests/units/unit_exec_in_sequence.cf Q ".../bin/echo Hello": Hello world - 46k/219 -> Last 1 QUOTEed lines were generated by "/bin/echo Hello world - 46k/219" Q ".../bin/ls": agent.c Q ".../bin/ls": agentdiagnostic.c Q ".../bin/ls": agentdiagnostic.o Q ".../bin/ls": agent.o Q ".../bin/ls": args.c Q ".../bin/ls": args.lo Q ".../bin/ls": args.o ... Q ".../bin/ls": verify_reports.o Q ".../bin/ls": verify_storage.c Q ".../bin/ls": verify_storage.o -> Last 288 QUOTEed lines were generated by "/bin/ls" atlas$
When setting up cf-serverd, you might see the error message
Unspecified server refusal
This means that cf-serverd is unable or is unwilling to
authenticate the connection from your client machine. The message is
generic: it is deliberately non-specific so that anyone attempting to
attack or exploit the service will not be given information which
might be useful to them. There is a simple checklist for curing this
problem:
skipidentify and skipverify to decouple DNS from the
the authentication.
body server control
{
allowconnects => { "127.0.0.1" , "::1" ...etc };
allowallconnects => { "127.0.0.1" , "::1" ...etc };
trustkeysfrom => { "127.0.0.1" , "::1" ...etc };
}
cf-key.
Always remember that you can run cfengine in verbose or debugging modes to see how the authentication takes place:
cf-agent -v cf-serverd -v
cf-agent reports that access is denied regardless of the nature
of the error, to avoid giving away information which might be used by
an attacker. To find out the real reason for a denial, use verbose ‘-v’ or
even debugging mode ‘-d2’.
The key exchange model used by cfengine is based on that used by OpenSSH. It is a peer to peer exchange model, not a central certificate authority model. This means that there are no scalability bottlenecks (at least by design, though you might introduce your own if you go for an overly centralized architecture).
The problem of key distribution is the conundrum of every public key infrastructure. Key exchange is handled automatically by cfengine and all you need to do is to decide which keys to trust.
When public keys are offered to a server, they could be accepted automatically on trust because no one is available to make a decision about them. This would lead to a race to be the first to submit a key claiming identity.
Even with DNS checks for correct name/IP address correlation (turned
off with skipverify), it might be possible to submit a false
key to a server.
The server cf-serverd blocks the acceptance of unknown keys by
default. In order to accept such a new key, the IP address of the
presumed client must be listed in the trustkeysfrom stanza of a
server bundle (these bundles can be placed in any file). Once a
key has been accepted, it will never be replaced with a new key, thus
no more trust is offered or required.
Once you have arranged for the right to connect to the server, you
must decide which hosts will have access to which files. This is done
with access rules.
bundle server access_rules()
{
access:
"/path/file"
admit => { "127.0.0.1", "127.0.0.2", "127.0.0.3" },
deny => { "192\..*" };
}
On the client side, i.e. cf-runagent and cf-agent, there are three issues:
encrypt).
Because there are two clients for connecting to cf-serverd
(cf-agent and cf-runagent), there are also two ways of
managing trust of server keys by a client. One is an automated option, setting the option
trustkey in a copy_from stanza, e.g.
body copy_from example
{
# .. other settings ..
trustkey => "true";
}
Another way is to run cf-runagent in interactive mode. When you run cf-runagent, unknown
server keys are offered to you interactively (as with ssh) for you to
accept or deny manually:
WARNING - You do not have a public key from host ubik.iu.hio.no = 128.39.74.25
Do you want to accept one on trust? (yes/no)
-->
Once public keys have been exchanged from client to server and from server to client, the issue of trust is solved according to public key authentication schemes. You only need to worry about trust when one side of a connection has never seen the other side before.
Often you will have a central server and many client satellites. Then
the best way to transfer all the keys is to set the trustkey
flags on server and clients sides to coincide with a time at which you
know that cf-agent will be run, and when a spoofer is unlikely
to be able to interfere.
This is a once-only task, and the chance of an attacker being able to spoof a key-transfer is small. It would require skill and inside-information about the exchange procedure, which would tend to imply that the trust model was already broken.
Another approach would be to run cf-runagent against all the hosts
in the group from the central server and accept the keys one by one,
by hand, though there is little to be gained from this.
Trusting a host for key exchange is unavoidable. There is no clever way to avoid it. Even transferring the files manually by diskette, and examining every serial number of the computers you have, the host has to trust the information you are giving it. It is all based on assertion. You can make it almost impossible for keys to be faked or attacked, but you cannot make it absolutely impossible. Security is about managing reasonable levels of risk, not about magic.
All security is based on a moment of trust, that is granted by a user at some point in time – and is assumed thereafter (once given, hard to rescind). Cryptographic key methods only remove the need for a repeat of the trust decision. After the first exchange, trust is no longer needed, because they keys allow identity to be actually verified.
Even if you leave the trust options switched on, you are not blindly trusting the hosts you know about. The only potential insecurity lies in any new keys that you have not thought about. If you use wildcards or IP prefixes in the trust rules, then other hosts might be able to spoof their way in on trust because you have left open a hole for them to exploit. That is why it is recommended to return the system to the default state of zero trust immediately after key transfer, by commenting out the trust options.
It is possible, though somewhat laborious to transfer the keys out of
band, by copying /var/cfengine/ppkeys/localhost.pub to
/var/cfengine/ppkeys/user-aaa.bbb.ccc.mmm (assuming IPv4) on
another host. e.g.
localhost.pub -> root-128.39.74.71.pub
This would be a silly way to transfer keys between nearby hosts that you control yourself, but if transferring to long distance, remote hosts it might be an easier way to manage trust.
CFEngine normally runs as user "root" (except on Windows which does not normally have a root user), i.e. a privileged administrator. If other users are to be granted access to the system, they must also generate a key and go through the same process. In addition, the users must be added to the server configuration file.
CFEngine provides encryption for keeping file contents private during transfer. It is assumed that users will use this judiciously. There is nothing to be gained by encrypting the transfer of public files – overt use of encryption just contributes to global warming, burning unnecessary CPU cycles without offering any security.
The main role for encryption in configuration management is for authentication. CFEngine always uses encryption during authentication, so none of the encryption settings affect the security of authentication.
Everything in cfengine 3 can be interpreted as a promise. Promises can be made about all kinds of different subjects, from file attributes, to the execution of commands, to access control decisions and knowledge relationships.
This simple but powerful idea allows a very practical uniformity in cfengine syntax. There is only one grammatical form for statements in the language that you need to know and it looks generically like this:
type:
classes::
"promiser" -> { "promisee1", "promisee2", ... }
attribute_1 => value_1,
attribute_2 => value_2,
...
attribute_n => value_n;
We speak of a promiser (the abstract object making the promise), the promisee is the abstract object to whom the promise is made, and them there is a list of associations that we call the `body' of the promise, which together with the promiser-type tells us what it is all about.
Not all of these elements are necessary every time. Some promises contain a lot of implicit behaviour. In other cases we might want to be much more explicit. For example, the simplest promise looks like this:
commands:
"/bin/echo hello world";
This promise has default attributes for everything except the `promiser', i.e. the command string that promises to execute. A more complex promise contains many attributes:
files:
"/home/mark/tmp/test_plain" -> "system blue team",
comment => "This comment follows the rule for knowledge integration",
perms => users("@(usernames)"),
create => "true";
The list of promisees is not used by cfengine except for documentation, just as the comment attribute (which can be added to any promise) has no actual function other than to provide more information to the user in error tracing and auditing.
You see several kinds of object in this example. All literal strings
(e.g. "true") in cfengine 3 must be quoted. This provides
absolute consistency and makes type-checking easy and error-correction
powerful. All function-like objects (e.g. users("..")) are either builtin
special functions or parameterized templates which contain the `meat' of the right hand
side.
The words commands, and files are built-in promise
types. Promise types generally belong each to a particular component
of cfengine, as the components are designed to keep different kinds of
promises. A few types, such as vars, classes and
reports are common to all the different component bundles. You
will find a full list of the promise types that can be made by the
different components in the `bundles' chapters that follow.
When writing promises, get into the habit of giving every promise a comment that explains its intention.
Also, give related promises handles, or labels that can be used to refer to them by.
files:
"/var/cfengine/inputs"
handle => "update_policy",
comment => "Update the configuration from a master server",
perms => system("600"),
copy_from => mycopy("$(master_location)","$(policy_server)"),
depth_search => recurse("inf"),
file_select => input_files,
action => immediate;
If a promise affects another promise is some way, you can make the affected
promise one of the promisees, like this:
access:
"/master/cfengine/inputs" -> { "update_policy", "other_promisee" },
comment => "Grant access to policy to our clients",
handle => "serve_updates",
admit => { "217.77.34.*" };
Conversely, if a promise might depend on another in some (even indirect) way, document this too.
files:
"/var/cfengine/inputs"
comment => "Update the configuration from a master server",
handle => "update_policy",
depends_on => "serve_updates",
perms => system("600"),
copy_from => mycopy("$(master_location)","$(policy_server)"),
depth_search => recurse("inf"),
file_select => input_files,
action => immediate;
Get into the habit of adding the cause-effect lines of influence. Enterprise editions of cfengine will track the dependencies between these promises and map out impact analyses.
CFEngine allows you to group multiple promise statements into containers called bundles.
bundle agent identifier
{
commands:
"/bin/echo These commands are a silly way to use cfengine";
"/bin/ls -l";
"/bin/echo But they illustrate a point";
}
Bundles serve two purposes: they allow us to collect related promises under a single heading, like a subroutine, and they allow us to mix configuration for different parts of cfengine in the same file. The type of a bundle is the name of the component of cfengine for which it is intended.
For instance, we can make a self-contained example agent-server configuration by labelling the bundles:
#
# Not a complete example
#
bundle agent testbundle
{
files:
"/home/mark/tmp/testcopy"
comment => "Throwaway example...",
copy_from => mycopy("/home/mark/LapTop/words","127.0.0.1"),
perms => system,
depth_search => recurse("inf");
}
#
bundle server access_rules
{
access:
"/home/mark/LapTop"
admit => { "127.0.0.1" };
}
Another type of container in cfengine 3 is a `body' part. Body parts exist to hide complex parameter information in reusable containers. The right hand side of some attribute assignments use body containers to reduce the amount of in-line information and preserve readability. You cannot choose where to use bodies: either they are used or they are not used for a particular kind of attribute. What you can choose, however, is the name and number of parameters for the body; and you can make as many of them as you like: For example:
body copy_from mycopy(from,server)
{
source => "$(from)";
servers => { "$(server)" };
copy_backup => "true";
special_class::
purge => "true";
}
Notice also that classes can be used in bodies as well as parameters so that you can hide environmental adaptations in these bodies also. The classes used here are effectively ANDed with the classes under which the calling promise is defined.
When you type a promise into a cfengine bundle, the promise will be read by every cf-agent that reads the file, each time it is called into being. For some promises this is okay, but for others you only want to verify the promise once in a while, e.g. once per day or once per hour. There are two ways to say when and where a promise applies in cfengine:
promise-type:
class-expression::
promiser -> promisee
attribute => body,
ifvarclass => other-class-expression;
The class expression may contain words like ‘Hr12’, meaning from 12:00 p.m - 13:00 p.m., or ‘Hr12&Min05_10’, meaning between 12:05 and 12:10. Classes may also have spatial descriptors like ‘myhost’ or ‘solaris’, which decide which hosts in the namespace, or ‘ipv4_192_168_1_101’ which decides the location in IPv4 address space.
If the class expression is true, the promise can be considered made for the duration of the current execution.
CFEngine 3 has a new class predicate ifvarclass which is
ANDed with the normal class expression, and which is evaluated
together with the promise. It may contain variables as long as the
resulting expansion is a legal class expression.
CFEngine is controlled by a series of locks which prevent it from checking promises too often, and which prevent it from spending too long trying to verify promises it already verified recently. The locks work in such a way that you can start several cfengine processes simultaneously without them interfering with each other. You can control two things about each kind of action in the action sequence:
You can set these values either globally (for all actions) or for each action separately. If you set global and local values, the local values override the global ones. All times are written in units of minutes. Global setting is in the control body:
body agent control
{
ifelapsed => "60"; # one hour
}
or locally in the transaction bodies:
body action example
{
ifelapsed => "90"; # 1.5 hours
}
These locks do not prevent the whole of cf-agent from running, only atomic promise checks. Several different atoms can be run concurrently by different cf-agents. The locks ensure that atoms will never be started by two cf-agents at the same time, or too soon after a verification, causing contention and wasting CPU cycles.
A key difference in cfengine 3 compared to earlier versions is the presence of data types. Data types are a mechanism for associating values and checking consistency in a language. Once again, there is a simple pattern to types in cfengine.
The principle is very simple: types exist in order to match like a plug-socket relationship. In the examples above, you can see two places where types are used to match templates:
bundle TYPE name # matches TYPE to running agent
{
}
lvalues => rvalue constraints:
body TYPE name # matches TYPE => name in promise
{
}
Check these by identifying the words ‘agent’ and ‘copy_from’ in the examples above. Types are there to make configuration more robust.
CFEngine variables have two meta-types: scalars and lists. A scalar is a single value,
a list is a collection of scalars. Each scalar may have one of three types:
string, int or real. Typing is dynamic, so these are
interchangable in many instances. However arguments to special functions check legal
type for consistency.
Integer constants may use suffixes to represent large numbers.
CFEngine 3 has some simple rules for variable expansion. These make a couple of restrictions that enforce discipline of clarity and allow automatic dependency tracking in enterprise versions of cfengine.
Scalar variables are written ‘$(name)’ and they represent a single value at a time.
vars:
"longlist" slist => { @(shortlist), "plus", "plus" };
"shortlist" slist => { "you", "me" };
During list expansion, only local lists can be expanded, thus global list references have to be mapped into a local context if you want to use them for iteration. Instead of doing this in some arbitrary way, with possibility of name collisions, cfengine asks you to make this explicit. There are two possible approaches.
The first uses parameterization to map a global list into a local context.
#
# Show access of external lists.
#
# - to pass lists globally, use a parameter to dereference them
#
body common control
{
bundlesequence => { hardening(@(va.tmpdirs)) };
}
#########################################################
bundle common va
{
vars:
"tmpdirs" slist => { "/tmp", "/var/tmp", "/usr/tmp" };
}
##########################################################
bundle agent hardening(x)
{
classes:
"ok" expression => "any";
vars:
"other" slist => { "/tmp", "/var/tmp" };
reports:
ok::
"Do $(x)";
"Other: $(other)";
}
This alternative uses a direct `short-circuit' approach to map the global list into the local context.
#
# Show access of external lists.
#
body common control
{
bundlesequence => { hardening };
}
#########################################################
bundle common va
{
vars:
"tmpdirs" slist => { "/tmp", "/var/tmp", "/usr/tmp" };
}
##########################################################
bundle agent hardening
{
classes:
"ok" expression => "any";
vars:
"other" slist => { "/tmp", "/var/tmp" };
"x" slist => { @(va.tmpdirs) };
reports:
ok::
"Do $(x)";
"Other: $(other)";
}
cf_nullAs of CFEngine core version 3.1.0, the value ‘cf_null’ may be used as a NULL value within lists. This value is ignored in list variable expansion.
vars:
"empty_list" slist => { "cf_null" };
Array variables are written with ‘[’ and ‘]’ brackets, e.g.
bundle agent example
{
vars:
"component" slist => { "cf-monitord", "cf-serverd", "cf-execd" };
"array[cf-monitord]" string => "The monitor";
"array[cf-serverd]" string => "The server";
"array[cf-execd]" string => "The executor, not executioner";
commands:
"/bin/echo $(component) is"
args => "$(array[$(component)])";
}
Arrays are associative and may be of type scalar or list. Enumerated arrays are simply treated as a special case of associative arrays, since there are no numerical loops in cfengine. Special functions exist to extract lists of keys from array variables for iteration purposes.
Thus one could have written the example above in the form of the following example:
bundle agent array
{
vars:
"v[index_1]" string => "value_1";
"v[index_2]" string => "value_2";
"parameter_name" slist => getindices("v");
reports:
Yr2008::
"Found index: $(parameter_name)";
}
CFEngine takes a pragmatic point of view to ordering. When promising `scalar' attributes and properties, ordering is irrelevant and need not be considered. More complex patterned data structures require ordering to be preserved, e.g. editing in files. CFEngine solves this in a two-part strategy:
classes promises, upon
which later agent-bundle vars promises may depend. Place these
at the start of your configuration (see next item).
bundlesequence (possibly overridden by the -b or
--bundlesequence command line option).
vars
classes
outputs
interfaces
processes
storage
packages
commands
methods
files
databases
services
environments
reports
Within edit_line bundles in files promises
(See `File editing in cfengine 3' for important details),
the normal ordering is:
vars
classes
delete_lines
field_edits
insert_lines
replace_patterns
reports
As with the agent, common bundles are executed before any server bundles;
following this all server bundles are executed (the bundlesequence
is only used for cf-agent).
Within a server bundle, the promise types are unamgibuous.
Variables and classes are resolved in the same way as the agent.
On connection, access control must be handled first, then a role
request might be made once access has been granted. Thus ordering
is fully constrained by process with no additional freedoms.
Within a server bundle, the normal ordering is:
vars classes access roles
As with the agent, common bundles are executed before any monitor bundles;
following this all monitor bundles are executed (the bundlesequence
is only used for cf-agent).
Variables and classes are resolved in the same way as the agent.
Within a monitor bundle, the normal ordering is:
vars classes measurements reports
As with the agent, common bundles are executed before any knowledge bundles;
following this all knowledge bundles are executed (the bundlesequence
is only used for cf-agent).
Variables and classes are resolved in the same way as the agent.
Within a knowledge bundle, the normal ordering is:
vars classes topics occurrences inferences reports
There are no explicit loops in cfengine, instead there are lists. To make a loop, you simply refer to a list as a scalar and cfengine will assume a loop over all items in the list.
For example, in the examples below the list component has three
elements. The list as a whole may be referred to as
@(component), in order to pass the whole list to a promise
where a list is expected. However, if we write $(component),
i.e. the scalar variable, then cfengine assumes that it should substitute
each scalar from the list in turn, and thus iterate over the list
elements using a loop.
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"component" slist => { "cf-monitord", "cf-serverd", "cf-execd" };
"new_list" slist => { "cf-know", @(component) };
processes:
"$(component)" restart_class => canonify("start_$(component)");
commands:
"/bin/echo /var/cfengine/bin/$(component)"
ifvarclass => canonify("start_$(component)");
}
If a variable is repeated, its value is tied throughout the expression; so the output of:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"component" slist => { "cf-monitord", "cf-serverd", "cf-execd" };
"array[cf-monitord]" string => "The monitor";
"array[cf-serverd]" string => "The server";
"array[cf-execd]" string => "The executor, not executioner";
commands:
"/bin/echo $(component) is"
args => "$(array[$(component)])";
}
is as follows:
Q ".../bin/echo cf-mo": cf-monitord is The monitor -> Last 1 QUOTEed lines were generated by "/bin/echo cf-monitord is The monitor" Q ".../bin/echo cf-se": cf-serverd is The server -> Last 1 QUOTEed lines were generated by "/bin/echo cf-serverd is The server" Q ".../bin/echo cf-ex": cf-execd is The executor, not executioner -> Last 1 QUOTEed lines were generated by "/bin/echo cf-execd is The executor, not executioner"
One of the strengths of cfengine 3 is the ability to recognize and exploit patterns. All string patterns in cfengine 3 are matched using regular expressions. The preferred regular expression library is the Perl Compatible Regular Expression library. This is more powerful and more reliable than the default POSIX regular expression code and all users should make the PCRE library available during compilation if possible.
CFEngine has the ability to extract back-references from pattern matches. This makes sense in two cases. Back references are fragments of a string that match parenethetic expressions. For instance, suppose we have the string:
Mary had a little lamb ...
and apply the regular expression
"Mary ([^l]+)little (.*)"
The pattern matches the entire string, and it contains two parenthesized subexpressions, which respectively match the fragments `has a ' and `lamb ...'. The regular expression libraries assign three matches to this result, labelled 0, 1 and 2.
The zeroth value is the entire string matched by the total expression. The first value is the fragment matched by the first parenthesis, and so on.
Each time cfengine matches a string, these values are
assigned to a special variable context $(match.n).
The fragments can be referred to in the remainder of the promise.
There are two places where this makes sense. One is in pattern replacement
during file editing, and the other is in searching for files.
Consider the examples below:
bundle agent testbundle
{
files:
# This might be a dangerous pattern - see explanation in the next section
# on "Runaway change warning"
"/home/mark/tmp/cf([23])?_(.*)"
edit_line => myedit("second backref: $(match.2)");
}
There are other filenames that could match this pattern, but if, for
example, there were to exist a file /home/mark/tmp/cf3_test,
then we would have:
Note that because the pattern allows for an optional '2' or '3' to follow
the letters 'cf', it is possible that $(match.1) would contain the
empty string. For example, if there was a file named
/home/mark/tmp/cf_widgets, then we would have
Now look at the edit bundle. This takes a parameter (which is the
back-reference from the filename match), but it also uses back references to
replace shell comment lines with C comment lines (the same
approach is used to hash-comment lines in files). The back-reference
variables $(match.n) refer to the most recent pattern match, and
so in the ‘C_comment’ body, they do not refer to the filename components,
but instead to the hash-commented line in the ‘replace_patterns’ promise.
bundle edit_line myedit(parameter)
{
vars:
"edit_variable" string => "private edit variable is $(parameter)";
insert_lines:
"$(edit_variable)";
replace_patterns:
# replace shell comments with C comments
"#(.*)"
replace_with => C_comment,
select_region => MySection("New section");
}
########################################
# Bodies
########################################
body replace_with C_comment
{
replace_value => "/* $(match.1) */"; # backreference from replace_patterns
occurrences => "all"; # first, last, or all
}
########################################################
body select_region MySection(x)
{
select_start => "\[$(x)\]";
select_end => "\[.*\]";
}
Try this example on the file
[First section] one two three [New section] four #five six [final] seven eleven
The resulting file is edited like this:
[First section] one two three [New section] four /* cf3 */ six [final] seven eleven private edit variable is second backref: test
Be careful when using patterns to search for files that are altered by cfengine
if you are not using a file repository. Each time cfengine makes a change it
saves an old file into a copy like cf3_test.cf-before-edit. These
new files then get matched by the same expression above – because it ends
in the generic.*), or does not
specify a tail for the expression. Thus cfengine will happily edit backups
of the edit file too, and generate a recursive process, resulting in something
like the following:
cf3_test cf3_test.cf-before-edit
cf3_test~ cf3_test~.cf-before-edit.cf-before-edit
cf3_test~.cf-before-edit cf3_test~.cf-before-edit.cf-before-edit.cf-before-edit
Always try to be as specific as possible when specifying patterns. A lazy approach will often come back to haunt you.
The following example shows how you would hash-comment lines in a file using cfengine 3.
######################################################################
#
# HashCommentLines implemented in cfengine 3
#
######################################################################
body common control
{
version => "1.2.3";
bundlesequence => { "testbundle" };
}
########################################################
bundle agent testbundle
{
files:
"/home/mark/tmp/comment_test"
create => "true",
edit_line => comment_lines_matching;
}
########################################################
bundle edit_line comment_lines_matching
{
vars:
"regexes" slist => { "one.*", "two.*", "four.*" };
replace_patterns:
"^($(regexes))$"
replace_with => comment("# ");
}
########################################
# Bodies
########################################
body replace_with comment(c)
{
replace_value => "$(c) $(match.1)";
occurrences => "all";
}
When applying regular expressions in paths, the path will first be
split at the path separators, and each element matched
independently. For example, this makes it possible to write
expressions like "/home/.*/file" to match a single file inside
a lot of directories — the .* does not eat the whole string.
Note that whenever regular expressions are used in paths, the / is
always used as the path separator, even on Windows. However, on Windows, if
the pathname is interpreted literally (no regular expressions), then the
backslash is also recognized as the path separator. This is because the
backslash has a special (and potentially ambiguous) meaning in regular
expressions (a \d means the same as [0-9], but on Windows it
could also be a path separator and a directory named d).
The pathtype attribute allows you to force a specific behavior when
interpreting pathnames. By default, CFEngine looks at your pathname and
makes an educated guess as to whether your pathname contains a regular
expression. The values "literal" and "regex" explicitly force
CFEngine to interpret the pathname either one way or another.
(see the pathtype attribute).
body common control
{
bundlesequence => { "wintest" };
}
########################################
bundle agent wintest
{
files:
"c:/tmp/file/f.*" # "best guess" interpretation
delete => nodir;
"c:\tmp\file"
delete => nodir,
pathtype => "literal"; # force literal string interpretation
"C:/windows/tmp/f\d"
delete => nodir,
pathtype => "regex"; # force regular expression interpretation
}
########################################
body delete nodir
{
rmdirs => "false";
}
Note that the path ‘/tmp/gar.*’ will only match filenames like /tmp/gar, /tmp/garbage and /tmp/garden. It will not match filename like /tmp/gar/baz (because even though the ‘.*’ in a regular expression means "zero or more of any character", CFEngine restricts that to mean "zero or more of any character in a path component"). Correspondingly, CFEngine also restricts where you can use the ‘/’ character (you can't use it in a character class like ‘[^/]’ or in a parenthesized or repeated regular expression component.
This means that regular expressions which include "optional directory components" won't work. You can't have a files promise to tidy the directory ‘(/usr)?/tmp’. Instead, you need to be more verbose and specify ‘/usr/tmp|/tmp’, or even better, think declaratively and create an slist that contains both the strings ‘/tmp’ and ‘/usr/tmp’, and then allow CFEngine to iterate over the list!
This also means that the path ‘/tmp/.*/something’ will match files like /tmp/abc/something or /tmp/xyzzy/something. However, even though the pattern ‘.*’ means "zero or more of any character (except ‘/’)", CFEngine matches files bounded by directory separators. So even though the pathname /tmp//something is technically the same as the pathname /tmp/something, the regular expression ‘/tmp/.*/something’ will not match on the degenerate case of /tmp//something (or /tmp/something).
CFEngine uses the full power of regular expressions, but there are two “flavors” of regex. Because they behave somewhat differently (while still utilizing the same syntax), it is important to know which one is used for a particular component of CFEngine:
For example, the comment parameter in readstringarray
is an unanchored regex (See Function readstringarray). If you
specify the regular expression as "#.*", then on any line
which contains a pound sign, everything from there until the end
of the line will be removed as a comment. However, if you specify
the regular expression as "^#.*" (note the ‘^’ anchor
at the start of the regex), then only lines which start with a
‘#’ will be removed as a comment! If you want to ignore C-style
comment in a multi-line string, then you have to a bit more clever,
and use this regex: "(?s)/\*.*?\*/"
Conversely, delete_lines promises use anchored regular
expressions to delete lines. If our promise uses "bob:\d*
as a line-matching regex, then only the second line of this file
will be deleted (because only the second line starts with ‘bob:’
and is then followed exclusively by digits, all the way to the end of
the string).
bobs:your:uncle bob:111770 thingamabob:1234 robert:bob:xyz i:am:not:bob
If CFEngine expects an unanchored regular expression, then finding
every line that contains the letters ‘bob’ is easy. You just
use the regex "bob". But if CFEngine expects an anchored
regular expression, then you must use ".*bob.*".
If you want to find every line that has a field which is exactly
‘bob’ with no characters before or after, then it is only a
little more complicated if CFEngine expects an unanchored regex:
"(^|:)bob(:|$)". But if CFEngine expects an anchored
regular expression, then it starts getting ugly, and you'd need to
use "bob:.*|.*:bob:.*|.*:bob".
Regular expressions are a complicated subject, and really are beyond the scope of this document. However, it is worth mentioning a couple of special topics that you might want to know of when using regular expressions.
The first is how to not get a backreference. If you want to have a
parenthesized expression that does not generate a back reference, there is a
special PCRE syntax to use. Instead of using () to bracket the piece
of a regular expression, use (?:) instead. For example, this will
match the filenames foolish, foolishly, bearish,
bearishly, garish, and garishly in the /tmp
directory. The variable $match.0 will contain the full filename, and
$match.1 will either contain the string ‘ly’ or the empty string.
But the (?:expression) which matches foo, bear,
or gar does not create a back-reference:
files:
"/tmp/(?:foo|bear|gar)ish(ly)?"
Another thing you might want to do is ignore capitalization. CFEngine is case-sensitive (in all things), so the files promise /tmp/foolish will not match the files /tmp/Foolish or /tmp/fOoLish, etc. There are two ways to acheive case-insensitivity. The first is to use character classes:
files:
"/tmp/[Ff][Oo][Oo][Ll][Ii][Ss][Hh]"
While this is certainly correct, it can also lead to unreadability. The PCRE patterns in CFEngine have another way of introducing case-insensitvity into a pattern:
files:
"/tmp/(?i:foolish)"
The (?i:) brackets impose case-insensitive matching on the text that
it surrounds, without creating a sub-expression. You could also write the
regular expression like this (but be aware that the two expressions are
different, and work slightly differently, so check the documentation for the
specifics):
files:
"/tmp/(?i)foolish"
The /s, /m, and /x switches from PCRE are also
available, but use them with great care!
Cfengine's philosophy and modus operandi is to make machines as self-reliant as possible. This is the path to scalability. Sometimes we want machines to be able to detect one another and sample each others' behaviour. This can be accomplished using probes and server functions.
For example, testing whether services are up and running can be a useful probe even from a local host. CFEngine has in-built functions for generically probing the environment; these are designed to encourage decentralized monitoring.
body common control
{
bundlesequence => { "test" };
}
###########################################################
bundle agent test
{
vars:
"hosts" slist => { "server1.example.org", "server2", "server3" };
"up_servers" int => selectservers("@(hosts)","80","","","100","alive_servers");
classes:
"someone_alive" expression => isgreaterthan("$(up_servers)","0");
"i_am_a_server" expression => regarray("up_servers","$(host)|$(fqhost)");
reports:
someone_alive::
"Number of active servers $(up_servers)" action => always;
"First server $(alive_servers[0]) fails over to $(alive_servers[1])";
}
Developers may note that the internal data-types follow a simple set of internal linked lists, as in the diagram below.
The cfengine tests directory contains a multitude of examples of cfengine 3 code. These instructions assume that you have all of your configuration in a single test file, such as the example in the distribution directory tests/units.
cf-promises. This requires no privileges.
An cf-agent will not execute a configuration that has not passed this test.
host$ cf-promises -f ./inputfile.cf
host$ src/cf-promises -f ./tests/units/unit_server_copy_localhost.cf
host$ src/cf-serverd -f ./tests/units/unit_server_copy_localhost.cf
host$ src/cf-agent -f ./tests/units/unit_server_copy_localhost.cf
Running cf-agent in verbose mode provides detailed information
about the state of the systems promises.
Outcome of version 1.2.3: Promises observed to be kept 99%,
Promises repaired 1%, Promises not repaired 0%
The log-file WORKDIR/promise.log contains the summary of these reports with timestamps. This is the simplest kind of high level audit record of the system.
To illustrate a complete configuration for agents and daemons, consider the following example code, supplied in the inputs/ directory of the distribution. Comments indicate the thinking behind this starting point.
This file is the first file that cf-agent with no arguments
will try to look for. It should contain all of the basic
configuration settings, including a list of other files
to include. In normal operation, it must have a bundlesequence.
This file can stay fixed, except for extending the bundlesequence.
The bundlesequence acts like the `genetic makeup' of the
configuration. In a large configuration, you might want to have a
different bundlesequence for different classes of host, so that you
can build a complete system like a check-list from different
combinations of building blocks. You can construct different lists by
composing them from other lists, or you can use methods
promises as an alternative for composing bundles for different classes.
#######################################################
#
# promises.cf
#
#######################################################
body common control
{
# List the `genes' for this system..
bundlesequence => {
"update",
"garbage_collection",
"main",
"cfengine"
};
inputs => {
"update.cf",
"site.cf",
"library.cf"
};
}
#######################################################
# Now set defaults for all components' hard-promises
#######################################################
body agent control
{
# if default runtime is 5 mins, we need more for long jobs
ifelapsed => "15";
}
#######################################################
body monitor control
{
forgetrate => "0.7";
histograms => "true";
}
###########si###########################################
body executor control
{
splaytime => "1";
mailto => "cfengine_mail@example.org";
smtpserver => "localhost";
mailmaxlines => "30";
# Instead of a separate update script, now do this
exec_command => "$(sys.workdir)/bin/cf-agent -f failsafe.cf && $(sys.workdir)/bin/cf-agent";
}
#######################################################
body reporter control
{
reports => { "performance", "last_seen", "monitor_history" };
build_directory => "/tmp/nerves";
report_output => "html";
}
#######################################################
body runagent control
{
hosts => {
"127.0.0.1"
# , "myhost.example.com:5308", ...
};
}
#######################################################
body server control
{
allowconnects => { "127.0.0.1" , "::1" };
allowallconnects => { "127.0.0.1" , "::1" };
trustkeysfrom => { "127.0.0.1" , "::1" };
# Make updates and runs happen in one
cfruncommand =>
"$(sys.workdir)/bin/cf-agent -f failsafe.cf && $(sys.workdir)/bin/cf-agent";
allowusers => { "root" };
}
Use this file to add your site-specific configuration.
Common bundles can be used to define global variables.
Otherwise, unqualified variables are local to the bundle in which
they are defined – however they can be access by
writing $(bundle_name.variable_name).
#######################################################
#
# site.cf
#
#######################################################
bundle common g
{
vars:
SuSE::
"crontab" string => "/var/spool/cron/tabs/root";
!SuSE::
"crontab" string => "/var/spool/cron/crontabs/root";
}
The cfengine bundle below detects whether cfengine 2 is already
running on the host or not, and if so attempts to kill off old daemon
processes and encapsulate the agent. It also looks for rules in the
old cfengine configuration that would potentially spoil cfengine 3's
control of the system: the last thing we want is for cfengine 2 and
cfengine 3 to fight each other for control of the system. CFEngine 3
tries to edit an existing crontab entry to replace any references to
cfexecd with cf-execd; if none are found it will add a 5
minute run schedule. You should never put cf-agentor
cf-agent directly inside cron without the cf-execd
wrapper.
#######################################################
# Start with cfengine itself
#######################################################
bundle agent cfengine
{
classes:
"integrate_cfengine2"
and => {
fileexists("$(sys.workdir)/inputs/cfagent.conf"),
fileexists("$(sys.workdir)/bin/cfagent")
};
vars:
"cf2bits" slist => { "cfenvd", "cfservd", "cfexecd" };
commands:
integrate_cfengine2::
"$(sys.workdir)/bin/cfagent"
action => longjob;
files:
# Warn about rules relating to cfengine 2 in inputs - could conflict
"$(sys.workdir)/inputs/.*"
comment => "Check if there are still promises about cfengine 2 that need removing",
edit_line => DeleteLinesMatching(".*$(cf2bits).*"),
file_select => OldCf2Files,
action => WarnOnly;
# Check cf-execd and schedule is in crontab
"$(g.crontab)"
edit_line => upgrade_cfexecd,
classes => define("exec_fix");
processes:
exec_fix::
"cron" signals => { "hup" };
}
#######################################################
# General site issues can be in bundles like this one
#######################################################
bundle agent main
{
vars:
"component" slist => { "cf-monitord", "cf-serverd" };
# - - - - - - - - - - - - - - - - - - - - - - - -
files:
"$(sys.resolv)" # test on "/tmp/resolv.conf" #
create => "true",
edit_line => resolver,
edit_defaults => def;
# Uncomment this to perform a change-detection scan
# "/usr"
# changes => lay_trip_wire,
# depth_search => recurse("inf"),
# action => measure;
processes:
"cfenvd" signals => { "term" };
# Uncomment this when you are ready to upgrade the server
#
# "cfservd" signals => { "term" };
#
# Now make sure the new parts are running, cf-serverd will fail if
# the old server is still running
"$(component)" restart_class => canonify("start_$(component)");
# - - - - - - - - - - - - - - - - - - - - - - - -
commands:
"$(sys.workdir)/bin/$(component)"
ifvarclass => canonify("start_$(component)");
}
This section takes a backup of a user home directory. This is especially useful for a single laptop or personal workstation that does not have a regular external backup. If a user deletes a file by accident, this shadow backup might contain the file even while travelling offline.
#######################################################
# Backup
#######################################################
bundle agent backup
{
files:
"/home/backup"
copy_from => cp("/home/mark"),
depth_search => recurse("inf"),
file_select => exclude_files,
action => longjob;
}
#######################################################
# Garbage collection issues
#######################################################
bundle agent garbage_collection
{
files:
"$(sys.workdir)/outputs"
delete => tidy,
file_select => days_old("3"),
depth_search => recurse("inf");
}
###########################################################
body file_select OldCf2Files
{
leaf_name => {
"promises\.cf",
"site\.cf",
"library\.cf",
"failsafe\.cf",
".*\.txt",
".*\.html",
".*~",
"#.*"
};
file_result => "!leaf_name";
}
###########################################################
body action measure
{
measurement_class => "Detect Changes in /usr";
ifelapsed => "240"; # 4 hours
expireafter => "240"; # 4 hours
}
Some basic anomaly detection: we respond with simple warnings if resource anomalies are detected.
#######################################################
# Anomaly monitoring
#######################################################
bundle agent anomalies
{
reports:
rootprocs_high_dev2::
"RootProc anomaly high 2 dev on $(mon.host) at $(mon.env_time)
measured value $(mon.value_rootprocs) av $(mon.av_rootprocs)
pm $(mon.dev_rootprocs)"
showstate => { "rootprocs" };
entropy_www_in_high&anomaly_hosts.www_in_high_anomaly::
"HIGH ENTROPY Incoming www anomaly high anomaly dev!!
on $(mon.host) at $(mon.env_time)
- measured value $(mon.value_www_in)
av $(mon.av_www_in) pm $(mon.dev_www_in)"
showstate => { "incoming.www" };
entropy_www_in_low.anomaly_hosts.www_in_high_anomaly::
"LOW ENTROPY Incoming www anomaly high anomaly dev!!
on $(mon.host) at $(mon.env_time)
- measured value $(svalue_www_in)
av $(av_www_in) pm $(dev_www_in)"
showstate => { "incoming.www" };
entropy_tcpsyn_in_low.anomaly_hosts.tcpsyn_in_high_dev2::
"Anomalous number of new TCP connections on $(mon.host)
at $(mon.env_time)
- measured value $(mon.value_tcpsyn_in)
av $(mon.av_tcpsyn_in) pm $(mon.dev_tcpsyn_in)"
showstate => { "incoming.tcpsyn" };
entropy_dns_in_low.anomaly_hosts.dns_in_high_anomaly::
"Anomalous (3dev) incoming DNS packets on $(mon.host)
at $(mon.env_time) - measured value $(mon.value_dns_in)
av $(av_dns_in) pm $(mon.dev_dns_in)"
showstate => { "incoming.dns" };
entropy_dns_in_low.anomaly_hosts.udp_in_high_dev2::
"Anomalous (2dev) incoming (non-DNS) UDP traffic
on $(mon.host) at $(mon.env_time) - measured value
$(mon.value_udp_in) av $(mon.av_udp_in) pm $(mon.dev_udp_in)"
showstate => { "incoming.udp" };
anomaly_hosts.icmp_in_high_anomaly.!entropy_icmp_in_high::
"Anomalous low entropy (3dev) incoming ICMP traffic
on $(mon.host) at $(mon.env_time) - measured value $(mon.value_icmp_in)
av $(mon.av_icmp_in) pm $(mon.dev_icmp_in)"
showstate => { "incoming.icmp" };
}
Server access rules are a touchy business. In an enterprise setting you generally want every host to allow a monitoring host to be able to download data, and a backup host to be able to access important data on every host. On a laptop or personal workstation, there might not be any reason to run a server for external use; however you might configure it as below to allow localhost access for testing.
#######################################################
# Server configuration
#######################################################
bundle server access_rules()
{
access:
"/home/mark/test_area"
admit => { "127.0.0.1" };
# Rule for cf-runagent
"/home/mark/.cfagent/bin/cf-agent"
admit => { "127.0.0.1" };
# New in cf3 - RBAC with cf-runagent
roles:
".*" authorize => { "mark" };
}
This file should rarely if ever change. Should you ever change it (or when you upgrade CFEngine), take special care to ensure the old and the new CFEngine can parse and execute this file successfully. If not, you risk losing control of your system (that is, if CFEngine cannot successfully execute this set of promises, it has no mechanism for distributing new policy files).
By default, the policy defined in update.cf is executed from two sets
of promise bodies. The “usual” one (defined in the bundlesequence
in promises.cf) and another in the backup/failsafe bundlesequence
(defined in failsafe.cf).
#########################################################
#
# update.cf
#
#########################################################
bundle agent update
{
vars:
"master_location" string => "/your/master/cfengine-inputs";
files:
# Update the configuration
"/var/cfengine/inputs"
perms => system("600"),
copy_from => mycopy("$(master_location)","localhost"),
depth_search => recurse("inf"),
action => immediate;
# Update the software cache
"/var/cfengine/bin"
perms => system("700"),
copy_from => mycopy("/usr/local/sbin","localhost"),
depth_search => recurse("inf"),
action => immediate;
}
############################################
body perms system(p)
{
mode => "$(p)";
}
############################################
body file_select cf3_files
{
leaf_name => { "cf-.*" };
file_result => "leaf_name";
}
#########################################################
body copy_from mycopy(from,server)
{
source => "$(from)";
compare => "digest";
}
#########################################################
body action immediate
{
ifelapsed => "1";
}
This file should probably never change. The only job of failsafe.cf is
to execute the update bundle in a “standalone” context should there be
a syntax error somewhere in the main set of promises. In this way, if a
client machine's policies are ever corrupted after downloading erroneous
policy from a server, that client will have a failsafe method for downloading
a corrected policy once it becomes available on the server. Note that by
“corrupted” and “erroneous” we typically mean “broken via administrator
error” - mistakes happen, and the failsafe.cf file is CFEngine's way
of being prepared for that eventuality.
If you ever change failsafe.cf (or when you upgrade CFEngine), make sure the old and the new CFEngine can successfully parse and execute this file. If not, you risk losing control of your system (that is, if CFEngine cannot successfully execute this policy file, it has no failsafe/fallback mechanism for distributing new policy files).
#########################################################
#
# Failsafe file
#
#########################################################
body common control
{
bundlesequence => { "update" };
inputs => { "update.cf" };
}
############################################
body depth_search recurse(d)
{
depth => "$(d)";
}
The failsafe.cf file is to make sure that your system can upgrade gracefully to new versions even when mistakes are made.
As a general rule:
u_”). This
may mean that you create duplicate functionality, but that is okay in this
case to ensure a 100% functioning standalone update process). The promises
which manage the update process should not have any dependencies on any
other files.
A cfengine configuration will fail-over to the failsafe.cf
configuration
if it is unable to read or parse the contents successfully. That means
that any syntax errors you introduce (or any new features you utilize in a
configuration) will cause a
fail-over, because the parser will not be able to interpret the policy. If
the failover is due to the use of new features, they will not parse until the
software itself has been updated (so we recommend that you always update
CFEngine before updating policy to use new features). If you accidentally
cause a bad (i.e., unparseable) policy to be distributed to client machines,
the failsafe.cf policy on those machines will run (and will eventually
download a working policy, once you fix it on the policy host).
The failsafe.cf file should be able to download the latest master configuration from source always.
#######################################################
#
# failsafe.cf
#
#######################################################
body common control
{
bundlesequence => { "update" };
}
#########################################################
bundle agent update
{
files:
"/var/cfengine/inputs"
perms => system,
copy_from => mycopy("/home/mark/cfengine-inputs","localhost"),
file_select => cf3_files,
depth_search => recurse("inf");
"/var/cfengine/bin"
perms => system,
copy_from => mycopy("/usr/local/sbin","localhost"),
file_select => cf3_files,
depth_search => recurse("inf");
}
#########################################################
body perms system
{
mode => "0700";
}
#########################################################
body depth_search recurse(d)
{
depth => "$(d)";
}
############################################
body file_select cf3_files
{
leaf_name => { "cf-.*" };
file_result => "leaf_name";
}
#########################################################
body copy_from mycopy(from,server)
{
source => "$(from)";
servers => { "$(server)" , "failover.domain.tld" };
#copy_backup => "true";
#trustkey => "true";
encrypt => "true";
}
If the copy_backup option is true, cfengine will keep a single
previous version of the file before copy, if the value is ‘timestamp’
cfengine keeps time-stamped versions either in the location of the file, or in the
file repository if one is defined. The trustkey option should normally
be commented out so that public keys are only exchanged under controlled conditions.
The update should optionally include an update of software so that a single failover from a configuration that is `too new' for the software will still correct itself once the new software is available.
#######################################################
#
# update.cf
#
#######################################################
bundle agent update
{
files:
"/var/cfengine/inputs"
perms => system("600"),
copy_from => mycopy("/home/mark/cfengine-inputs","localhost"),
depth_search => recurse("inf");
"/var/cfengine/bin"
perms => system("700"),
copy_from => mycopy("/usr/local/sbin","localhost"),
file_select => cf3_files,
depth_search => recurse("inf");
}
############################################
body perms system(p)
{
mode => "$(p)";
}
############################################
body file_select cf3_files
{
leaf_name => { "cf-.*" };
file_result => "leaf_name";
}
#########################################################
body copy_from mycopy(from,server)
{
source => "$(from)";
compare => "digest";
}
While promises to configure your system are entirley user-defined, the details of the operational behaviour of the cfengine software is of course hard-coded. You can still configure the details of this behaviour using the control promise bodies. Control behaviour is defined in bodies because the actual promises are fixed and you only change their details within sensible limits.
Note that in cfengine's previous versions, the control part of
the configuration contained a mixture of internal control parameters
and user definitions. There is now a cleaner separation in
cfengine 3. User defined behaviour requires a promise, and must
therefore be defined in a bundle.
Below is a list of the control parameters for the different components (Agents and Daemons2) of the cfengine software.
common control promises
body common control
{
inputs => {
"update.cf",
"library.cf"
};
bundlesequence => {
update("policy_host.domain.tld"),
"main",
"cfengine2"
};
output_prefix => "cfengine>";
version => "1.2.3";
}
|
The common control body refers to those promises that are
hard-coded into all the components of cfengine, and therefore affect
the behaviour of all the components.
bundlesequenceType: slist
Allowed input range: .*
Synopsis: List of promise bundles to verify in order
Example:
body common control
{
bundlesequence => {
update("policy_host.domain.tld"),
"main",
"cfengine2"
};
}
Notes:
The bundlesequence determines which of the compiled bundles
will be executed and in what order they will be executed. The list
refers to the names of bundles (which might be parameterized
function-like objects).
The order in which you execute bundles can affect the outcome of your promises. In general you should always define variables before you use them.
The bundlesequence is like a genetic makeup of a machine. The bundles
act like characteristics of the systems. If you want different systems to have
different bundlesequences, distinguish them with classes:
webservers::
bundlesequence => { "main", "web" };
others::
bundlesequence => { "main", "otherstuff" };
If you want to add a basic common sequence to all sequences, then use global variable lists to do this:
body common control
{
webservers::
bundlesequence => { @(g.bs), "web" };
others::
bundlesequence => { @(g.bs), "otherstuff" };
}
bundle common g
{
vars:
"bs" slist => { "main", "basic_stuff" };
}
Default value:
There is no default value for bundlesequence, and the absence of a
bundlesequence will cause a compilation error. A bundlesequence may
also be specified using the -b or --bundlesequence command line
option.
ignore_missing_bundlesType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: If any bundles in the bundlesequence do not exist, ignore and continue
Example:
ignore_missing_bundles => "true";
Notes:
This authorizes the bundlesequence to contain possibly existent pluggable modules. It defaults to false, whereupon undefined bundles cause a fatal error in parsing, and a transition to failsafe mode.
ignore_missing_inputsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: If any input files do not exist, ignore and continue
Example:
ignore_missing_inputs => "true";
Notes:
The inputs lists determines which files are parsed by cfengine. Normally stringent security checks are made on input files to prevent abuse of the system by unauthorized users. Sometimes however, it is appropriate to consider the automatic plug-in of modules that might or might not exist. This option permits cfengine to list possible files that might not exist and continue `best effort' with those that do exist. The default of all Booleans is false, so the normal behaviour is to signal an error if an input is not found.
inputsType: slist
Allowed input range: .*
Synopsis: List of additional filenames to parse for promises
Example:
body common control
{
inputs => {
"update.cf",
"library.cf"
};
}
Notes:
The filenames specified are all assumed to be in the same directory as the
file which references them (this is usually $(sys.workdir)/inputs, but
may be overridden by the -f or --file command line option.
Default value:
There is no default value. If no filenames are specified, no other filenames will be included in the compilation process.
versionType: string
Allowed input range: (arbitrary string)
Synopsis: Scalar version string for this configuration
Example:
body common control
{
version => "1.2.3";
}
Notes:
The version string is used in error messages and reports.
This string should not contain the colon ‘:’ character, as this has a special meaning in the context of knowledge management. This restriction might be lifted later.
lastseenexpireafterType: int
Allowed input range: 0,99999999999
Default value: One week
Synopsis: Number of minutes after which last-seen entries are purged
Example:
body common control
{
lastseenexpireafter => "72";
}
Notes:
Default time is one week.
output_prefixType: string
Allowed input range: (arbitrary string)
Synopsis: The string prefix for standard output
Example:
body common control
{
output_prefix => "my_cf3";
}
Notes:
On native Windows versions of CFEngine (Nova and above), this string is also prefixed messages in the event log.
domainType: string
Allowed input range: .*
Synopsis: Specify the domain name for this host
Example:
body common control
{
domain => "example.org";
}
Notes:
There is no standard, universal or reliable way of determining the DNS domain name of a host, so it can be set explicitly to simplify discovery and name-lookup.
require_commentsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: Warn about promises that do not have comment documentation
Example:
body common control
{
common::
require_comments => "true";
}
Notes:
This may be used as a policy Quality Assurance measure, to remind
policy makers to properly document their promises. When true,
cf-promises will report loudly on promises that do not have
comments.
host_licenses_paidType: int
Allowed input range: 0,99999999999
Default value: 0
Synopsis: The number of licenses that you promise to have paid for by setting this value (legally binding for commercial license)
Example:
body common control
{
host_licenses_paid => "1000";
}
Notes:
Licensees of the commercial CFEngine releases have to make a promise in acceptance of contract terms by setting this value to the number of licenses they have paid for. This is tallied with the number of licenses granted. This declaration should be placed in all separate configuration files, e.g. failsafe.cf, promises.cf.
syslog_hostType: string
Allowed input range: [a-zA-Z0-9_$.:-]+
Synopsis: The name or address of a host to which syslog messages should be sent directly by UDP
Example:
body common control
{
syslog_host => "syslog.example.org";
syslog_port => "514";
}
Notes:
The hostname or IP address of a local syslog service to which all CFEngine's components may promise to send data. This feature is provided in CFEngine Nova and above.
syslog_portType: int
Allowed input range: 0,99999999999
Default value: 514
Synopsis: The port number of a UDP syslog service
Example:
body common control
{
syslog_host => "syslog.example.org";
syslog_port => "514";
}
Notes:
The UDP port of a local syslog service to which all CFEngine's components may promise to send data. This feature is provided in CFEngine Nova and above.
fips_modeType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: Activate full FIPS mode restrictions
Example:
body common control
{
fips_mode => "true";
}
Notes:
Appears as of Nova 2.0. If CFEngine commercial editions this value may be set to avoid the use of old deprecated algorithms that are no longer FIPS 140-2 compliant. If not set, there is some degree of compatibility with older versions and algorithms. During an upgrade, setting this parameter can cause a lot of recomputation of checksums etc. Government bodies starting with Nova 2.0 or higher should set this to ‘true’ from the start.
agent control promises
body agent control
{
123_456_789::
domain => "mydomain.com";
123_456_789_111::
auditing => "true";
any::
fullencryption => "true";
}
|
Settings describing the details of the fixed behavioural promises made by
cf-agent. For example:
abortclassesType: slist
Allowed input range: .*
Synopsis: A list of classes which if defined lead to termination of cf-agent
Example:
body agent control
{
abortclasses => { "danger.*", "should_not_continue" };
}
Notes:
A list of class regular expressions that cf-agent will watch
out for. If any matching class becomes defined, it will cause the
current execution of cf-agent to be aborted. This may be used
for validation, for example. To handle class expressions, simply create
an alias for the expression with a single name.
abortbundleclassesType: slist
Allowed input range: .*
Synopsis: A list of classes which if defined lead to termination of current bundle
Example:
This example shows how to use the feature to validate input to a method bundle.
body common control
{
bundlesequence => { "testbundle" };
version => "1.2.3";
}
###########################################
body agent control
{
abortbundleclasses => { "invalid.*" };
}
###########################################
bundle agent testbundle
{
vars:
"userlist" slist => { "xyz", "mark", "jeang", "jonhenrik", "thomas", "eben" };
methods:
"any" usebundle => subtest("$(userlist)");
}
###########################################
bundle agent subtest(user)
{
classes:
"invalid" not => regcmp("[a-z]{4}","$(user)");
reports:
!invalid::
"User name $(user) is valid at exactly 4 letters";
# abortbundleclasses will prevent this from being evaluated
invalid::
"User name $(user) is invalid";
}
Notes:
A list of regular expressions for classes, or class expressions that
cf-agent will watch out for. If any of these classes becomes
defined, it will cause the current bundle to be aborted. This may be
used for validation, for example.
addclassesType: slist
Allowed input range: .*
Synopsis: A list of classes to be defined always in the current context
Example:
Add classes adds global, literal classes. The only predicates available during the control section are hard-classes.
any::
addclasses => { "My_Organization" }
solaris::
addclasses => { "some_solaris_alive", "running_on_sunshine" };
Notes:
Another place to make global aliases for system hardclasses. Classes here are added unqeuivocally to the system. If classes are used to predicate definition, then they must be defined in terms of global hard classes.
agentaccessType: slist
Allowed input range: .*
Synopsis: A list of user names allowed to execute cf-agent
Example:
agentaccess => { "mark", "root", "sudo" };
Notes:
A list of user names that will be allowed to attempt execution of the current configuration. This is mainly a sanity check rather than a security measure.
agentfacilityType: (menu option)
Allowed input range:
LOG_USERLOG_DAEMONLOG_LOCAL0LOG_LOCAL1LOG_LOCAL2LOG_LOCAL3LOG_LOCAL4LOG_LOCAL5LOG_LOCAL6LOG_LOCAL7
Default value: LOG_USER
Synopsis: The syslog facility for cf-agent
Example:
agentfacility => "LOG_USER";
Notes:
Sets the agent's syslog facility level. See the manual pages for syslog. This is ignored on Windows, as CFEngine Nova creates event logs.
auditingType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false flag to activate the cf-agent audit log
Example:
body agent control
{
auditing => "true";
}
Notes:
If this is set, cfengine will perform auditing on promises in the
current configuration. This means that all details surrounding the
verification of the current promise will be recorded in the audit
database. The database may be inspected with cf-report, or
cfshow in cfengine 2.
binarypaddingcharType: string
Allowed input range: (arbitrary string)
Default value: space (ASC=32)
Synopsis: Character used to pad unequal replacements in binary editing
Example:
body agent control
{
binarypaddingchar => "#";
}
Notes:
When editing binary files, it can be dangerous to replace a text string with one that is longer or shorter as byte references and jumps would be destroyed. CFEngine will therefore not allow replacements that are larger in size than the original, but shorter strings can be padded out to the same length.
Default value:
The binarypaddingchar defaults to the empty string (i.e., no padding)
bindtointerfaceType: string
Allowed input range: .*
Synopsis: Use this interface for outgoing connections
Example:
bindtointerface => "192.168.1.1";
Notes:
On multi-homed hosts, the server and client can bind to a specific interface for server traffic. The IP address of the interface must be given as the argument, not the device name.
hashupdatesType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false whether stored hashes are updated when change is detected in source
Example:
body agent control
{
hashupdates => "true";
}
Notes:
If ‘true’ the stored reference value is updated as soon as a warning message has been given. As most changes are benign (package updates etc) this is a common setting.
childlibpathType: string
Allowed input range: .*
Synopsis: LD_LIBRARY_PATH for child processes
Example:
body agent control
{
childlibpath => "/usr/lcoal/lib:/usr/local/gnu/lib";
}
Notes:
This string may be used to set the internal LD_LIBRARY_PATH
environment of the agent.
checksum_alert_timeType: int
Allowed input range: 0,60
Default value: 10 mins
Synopsis: The persistence time for the checksum_alert class
Example:
body agent control
{
checksum_alert_time => "30";
}
Notes:
When checksum changes trigger an alert, this is registered as a persistent class. This value determines the longevity of that class.
defaultcopytypeType: (menu option)
Allowed input range:
mtimeatimectimedigesthashbinary
Default value: ctime or mtime differ
Synopsis: (null)
Example:
body agent control
{
#...
defaultcopytype => "digest";
}
Notes:
Sets the global default policy for comparing source and image in copy transactions.
dryrunType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: All talk and no action mode
Example:
body agent control
{
dryrun => "true";
}
Notes:
If set in the configuration, cfengine makes no changes to a system, only reports what it needs to do.
editbinaryfilesizeType: int
Allowed input range: 0,99999999999
Default value: 100000
Synopsis: Integer limit on maximum binary file size to be edited
Example:
body agent control
{
edibinaryfilesize => "10M";
}
Notes:
The global setting for the file-editing safety-net for binary files (this
value may be overridden on a per-promise basis with max_file_size,
See edit_defaults in files. The default value for editbinaryfilesize
is 100k. Note the use of special units is allowed,
See Datatypes in cfengine 3, for a list of permissible suffixes.
When setting limits, the limit on editing binary files should generally be set higher than for text files.
editfilesizeType: int
Allowed input range: 0,99999999999
Default value: 10000
Synopsis: Integer limit on maximum text file size to be edited
Example:
body agent control
{
editfilesize => "120k";
}
Notes:
The global setting for the file-editing safety-net (this value may be
overridden on a per-promise basis with max_file_size,
See edit_defaults in files. The default value for editfilesize is
100k. Note the use of special units is allowed,
See Datatypes in cfengine 3, for a list of permissible suffixes.
environmentType: slist
Allowed input range: [A-Za-z0-9_]+=.*
Synopsis: List of environment variables to be inherited by children
Example:
body common control
{
bundlesequence => { "one" };
}
body agent control
{
environment => { "A=123", "B=456", "PGK_PATH=/tmp"};
}
bundle agent one
{
commands:
"/usr/bin/env";
}
Notes:
This may be used to set the runtime environment of the agent process. The values of environment variables are inherited by child commands. Some interactive programs insist on values being set, e.g.
# Required by apt-cache, debian
environment => { "LANG=C"};
exclamationType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: true
Synopsis: true/false print exclamation marks during security warnings
Example:
body agent control
{
exclamation => "false";
}
Notes:
This affects only the output format of warnings.
expireafterType: int
Allowed input range: 0,99999999999
Default value: 1 min
Synopsis: Global default for time before on-going promise repairs are interrupted
Example:
body action example
{
ifelapsed => "120"; # 2 hours
expireafter => "240"; # 4 hours
}
Notes:
The locking time after which cfengine will attempt to kill and restart its attempt to keep a promise.
files_single_copyType: slist
Allowed input range: (arbitrary string)
Synopsis: List of filenames to be watched for multiple-source conflicts
Example:
body agent control
{
single_copy => { "/etc/.*", "/special/file" };
}
Notes:
This list of regular expressions will ensure that files matching the
patterns of the list are never copied from more than one source during
a single run of cf-agent. This may be considered a protection
against accidential overlap of copies from diverse remote sources, or
as a first-come-first-served disambiguation tool for lazy-evaluation
of overlapping file-copy promises.
files_auto_defineType: slist
Allowed input range: (arbitrary string)
Synopsis: List of filenames to define classes if copied
Example:
body agent control
{
files_auto_define => { "/etc/syslog\.c.*", "/etc/passwd" };
}
Notes:
Classes are automatically defined by the files that are copied. The file is named according to the prefixed `canonization' of the file name. Canonization means that non-identifier characters are converted into underscores. Thus /etc/passwd would canonize to ‘_etc_passwd’. The prefix ‘auto_’ is added to clarify the origin of the class. Thus in the example the copying of /etc/passwd would lead to the class ‘auto__etc_passwd’ being defined automatically.
hostnamekeysType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false label ppkeys by hostname not IP address
Example:
body server control
{
hostnamekeys => "true";
}
Notes:
Client side choice to base key associations on host names rather than IP address. This is useful for hosts with dynamic addresses.
This feature has been deprecated since 3.1.0. Host identification is now handled transparently.
ifelapsedType: int
Allowed input range: 0,99999999999
Default value: 1
Synopsis: Global default for time that must elapse before promise will be rechecked
Example:
#local
body action example
{
ifelapsed => "120"; # 2 hours
expireafter => "240"; # 4 hours
}
# global
body agent control
{
ifelapsed => "180"; # 3 hours
}
Notes:
This overrides the global settings. Promises which take a long time to
verify should usually be protected with a long value for this
parameter. This serves as a resource `spam' protection. A cfengine
check could easily run every 5 minutes provided resource intensive
operations are not performed on every run. Using time classes like
Hr12 etc., is one part of this strategy; using ifelapsed
is another which is not tied to a specific time.
informType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false set inform level default
Example:
body agent control
{
inform => "true";
}
Notes:
Equivalent to (and when present, overrides) the command line option ‘-I’. Sets the default output level `permanently' within the class context indicated.
Every promiser makes an implicit default promise to use output settings declared
using outputs promises.
intermittencyType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false store detailed recordings of last observed time for all client-server connections for reliability assessment (false)
Example:
reports:
"Comment"
intermittency => "0.5";
Notes:
Report on cfengine peers in the neighbourhood watch whose observed irregularity of connection exceeds 0.5 scaled entropy units, meaning that they show an erratic pattern of connection.
max_childrenType: int
Allowed input range: 0,99999999999
Default value: 1 concurrent agent promise
Synopsis: Maximum number of background tasks that should be allowed concurrently
Example:
body runagent control
{
max_children => "10";
}
# or
body agent control
{
max_children => "10";
}
Notes:
For the run-agent this represents the maximum number of forked background processes allowed when parallelizing connections to servers. For the agent it represents the number of background jobs allowed concurrently. Background jobs often lead to contention of the disk resources slowing down tasks considerably; there is thus a law of diminishing returns.
maxconnectionsType: int
Allowed input range: 0,99999999999
Default value: 30 remote queries
Synopsis: Maximum number of outgoing connections to cf-serverd
Example:
# client side
body agent control
{
maxconnections => "1000";
}
# server side
body server control
{
maxconnections => "1000";
}
Notes:
Watch out for kernel limitations for maximum numbers of open file descriptors which can limit this.
mountfilesystemsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false mount any filesystems promised
Example:
body agent control
{
mountfilesystems => "true";
}
Notes:
Issues the generic command to mount file systems defined in the file system table.
nonalphanumfilesType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false warn about filenames with no alphanumeric content
Example:
body agent control
{
nonalphanumericfiles => "true";
}
Notes:
This test is applied in all recursive/depth searches.
repcharType: string
Allowed input range: .
Default value: _
Synopsis: The character used to canonize pathnames in the file repository
Example:
body agent control
{
repchar => "_";
}
Notes:
default_repositoryType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Default value: in situ
Synopsis: Path to the default file repository
Example:
body agent control
{
default_repository => "/var/cfengine/repository";
}
Notes:
If defined the default repository is the location where versions of files altered by cfengine are stored. This should be understood in relation to the policy for ‘backup’ in copying, editing etc. If the backups are time-stamped, this becomes effective a version control repository.
secureinputType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false check whether input files are writable by unauthorized users
Example:
body agent control
{
secureinput => "true";
}
Notes:
If this is set, the agent will not accept an input file that is not owned by a privileged user.
sensiblecountType: int
Allowed input range: 0,99999999999
Default value: 2 files
Synopsis: Minimum number of files a mounted filesystem is expected to have
Example:
body agent control
{
sensiblecount => "20";
}
Notes:
sensiblesizeType: int
Allowed input range: 0,99999999999
Default value: 1000 bytes
Synopsis: Minimum number of bytes a mounted filesystem is expected to have
Example:
body agent control
{
sensiblesize => "20K";
}
Notes:
skipidentifyType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: Do not send IP/name during server connection because address resolution is broken
Example:
body agent control
{
skipidentify => "true";
}
Notes:
Hosts that are not registered in DNS cannot supply reasonable credentials for a secondary confirmation of their identity to a cfengine server. This causes the agent to ignore its missing DNS credentials.
suspiciousnamesType: slist
Allowed input range: List of names to warn about if found during any file search
Synopsis: (null)
Example:
body agent control
{
suspiciousnames => { ".mo", "lrk3", "rootkit" };
}
Notes:
If cfengine sees these names during recursive (depth) file searches it will warn about them.
syslogType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false switches on output to syslog at the inform level
Example:
body agent example
{
syslog => "true";
}
Notes:
track_valueType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false switches on tracking of promise valuation
Example:
body agent control
{
track_value => "true";
}
Notes:
If this is true, cfengine generates a log in
WORKDIR/state/cf_value.log of the estmated `business value' of
the system automation as a running log, value_kept, etc. The
format of the file is
date,sum value kept,sum value repaired,sum value notkept
timezoneType: slist
Allowed input range: (arbitrary string)
Synopsis: List of allowed timezones this machine must comply with
Example:
body agent control
{
timezone => { "MET", "CET", "GMT+1" };
}
Notes:
default_timeoutType: int
Allowed input range: 0,99999999999
Default value: 10 seconds
Synopsis: Maximum time a network connection should attempt to connect
Example:
body agent control
{
default_timeout => "10";
}
Notes:
The time is in seconds. It is not a guaranteed number, since it depends on system behaviour. under Linux, the kernel version plays a role, since not all system calls seem to respect the signals.
verboseType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false switches on verbose standard output
Example:
body agent control
{
verbose => "true";
}
Notes:
Equivalent to (and when present, overrides) the command line option ‘-v’. Sets the default output level `permanently' for this promise.
Every promiser makes an implicit default promise to use output settings declared
using outputs promises.
server control promises
body server control
{
allowconnects => { "127.0.0.1" , "::1" , ".*\.example\.org" };
allowallconnects => { "127.0.0.1" , "::1" , ".*\.example\.org" };
# Uncomment me under controlled circumstances
#trustkeysfrom => { "127.0.0.1" , "::1" , ".*\.example\.org" };
}
|
Settings describing the details of the fixed behavioural promises made by
cf-serverd.
Server controls are mainly about determining access policy for the
connection protocol: i.e. access to the server itself. Access to
specific files must be granted in addition.
cfruncommandType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Path to the cf-agent command or cf-execd wrapper for remote execution
Example:
body server control
{
cfruncommand => "/var/cfengine/bin/cf-agent";
}
Notes:
It is normal for this to point to the location of cf-agent but
it could also point to the cf-execd, or even another program at
your own risk.
maxconnectionsType: int
Allowed input range: 0,99999999999
Default value: 30 remote queries
Synopsis: Maximum number of connections that will be accepted by cf-serverd
Example:
# client side
body agent control
{
maxconnections => "1000";
}
# server side
body server control
{
maxconnections => "1000";
}
Notes:
Watch out for kernel limitations for maximum numbers of open file descriptors which can limit this.
denybadclocksType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: true
Synopsis: true/false accept connections from hosts with clocks that are out of sync
Example:
body server control
{
#..
denybadclocks => "true";
}
Notes:
A possible form of attack on the fileserver is to request files based on time by setting the clocks incorrectly. This option prevents connections from clients whose clocks are drifting too far from the server clock (where "too far" is currently defined as "more than an hour off"). This serves as a warning about clock asynchronization and also a protection against Denial of Service attempts based on clock corruption.
allowconnectsType: slist
Allowed input range: (arbitrary string)
Synopsis: List of IPs or hostnames that may connect to the server port
Example:
allowconnects => {
"127.0.0.1",
"::1",
"200\.1\.10\..*",
"host\.domain\.tld",
"host[0-9]+\.domain\.com"
};
Notes:
If a client's identity matches an entry in this list it is granted to permission to send data to the server port. Clients who are not in this list may not connect or send data to the server.
See also the warning about regular expressions in allowallconnects.
denyconnectsType: slist
Allowed input range: (arbitrary string)
Synopsis: List of IPs or hostnames that may NOT connect to the server port
Example:
body server control
{
denyconnects => { "badhost\.domain\.evil", "host3\.domain\.com" };
}
Notes:
Hosts or IP addresses that are explicitly denied access. This should only be used in special circumstances. One should never grant generic access to everything and then deny special cases. Since the default server behaviour is to grant no access to anything, this list is unnecessary unless you have already granted access to some set of hosts using a generic pattern, to which you intend to make an exception.
See also the warning about regular expressions in allowallconnects.
allowallconnectsType: slist
Allowed input range: (arbitrary string)
Synopsis: List of IPs or hostnames that may have more than one connection to the server port
Example:
allowallconnects => {
"127.0.0.1",
"::1",
"200\.1\.10\..*",
"host\.domain\.tld",
"host[0-9]+\.domain\.com"
};
Notes:
This list of regular expressions matches hosts that are allowed to connect an umlimited number of times up to the maximum connection limit. Without this, a host may only connect once (which is a very strong constraint, as the host must wait for the TCP FIN_WAIT to expire before reconnection can be attempted).
In cfengine 2 this corresponds to AllowMultipleConnectionsFrom.
Note that 127.0.0.1 is a regular expression (i.e., “127 any character
0 any character 0 any character 1”), but this will only match the IP address
127.0.0.1. Take care with IP addresses and domain names, as the
hostname regular expression www.domain.com will potentially match more
than one hostname (e.g., wwwxdomain.com, in addition to the desired
hostname www.domain.com).
trustkeysfromType: slist
Allowed input range: (arbitrary string)
Synopsis: List of IPs from whom we accept public keys on trust
Example:
body server control
{
trustkeysfrom => { "10\.0\.1\.1", "192\.168\..*"};
}
Notes:
If connecting clients' public keys have not already been trusted, this allows us to say `yes' to accepting the keys on trust. Normally this should be an empty list except in controlled circumstances.
See also the warning about regular expressions in allowallconnects.
allowusersType: slist
Allowed input range: (arbitrary string)
Synopsis: List of usernames who may execute requests from this server
Example:
allowusers => { "cfengine", "root" };
Notes:
The usernames listed in this list are those asserted as public key identities during client-server connections. These may or may not correspond to system identities on the server-side system.
dynamicaddressesType: slist
Allowed input range: (arbitrary string)
Synopsis: List of IPs or hostnames for which the IP/name binding is expected to change
Example:
body server control
{
dynamicaddresses => { "dhcp_.*" };
}
Notes:
The addresses or hostnames here are expected to have non-permanent address-name bindings, we must therefor work harder to determine whether hosts credentials are trusted by looking for existing public keys in files that do not match the current hostname or IP.
This feature has been deprecated since 3.1.0. This is now handled transparently.
skipverifyType: slist
Allowed input range: (arbitrary string)
Synopsis: List of IPs or hostnames for which we expect no DNS binding and cannot verify
Example:
body server control
{
skipverify => { "special_host.*", "192.168\..*" };
}
Notes:
Server side decision to ignore requirements of DNS identity confirmation.
See also the warning about regular expressions in allowallconnects.
logallconnectionsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false causes the server to log all new connections to syslog
Example:
body server control
{
logallconnections => "true";
}
Notes:
If set, the server will record connection attempts in syslog.
logencryptedtransfersType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false log all successful transfers required to be encrypted
Example:
body server control
{
logencryptedtransfers => "true";
}
Notes:
If true the server will log all transfers of files which the server
requires to encrypted in order to grant access (see
ifencrypted) to syslog. These files are deemed to be
particularly sensitive.
hostnamekeysType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false store keys using hostname lookup instead of IP addresses
Example:
body server control
{
hostnamekeys => "true";
}
Notes:
Client side choice to base key associations on host names rather than IP address. This is useful for hosts with dynamic addresses.
This feature has been deprecated since 3.1.0. Host identification is now handled transparently.
auditingType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false activate auditing of server connections
Example:
body agent control
{
auditing => "true";
}
Notes:
If this is set, cfengine will perform auditing on promises in the
current configuration. This means that all details surrounding the
verification of the current promise will be recorded in the audit
database. The database may be inspected with cf-report, or
cfshow in cfengine 2.
bindtointerfaceType: string
Allowed input range: (arbitrary string)
Synopsis: IP of the interface to which the server should bind on multi-homed hosts
Example:
bindtointerface => "192.168.1.1";
Notes:
On multi-homed hosts, the server and client can bind to a specific interface for server traffic. The IP address of the interface must be given as the argument, not the device name.
serverfacilityType: (menu option)
Allowed input range:
LOG_USERLOG_DAEMONLOG_LOCAL0LOG_LOCAL1LOG_LOCAL2LOG_LOCAL3LOG_LOCAL4LOG_LOCAL5LOG_LOCAL6LOG_LOCAL7
Default value: LOG_USER
Synopsis: Menu option for syslog facility level
Example:
body server control
{
serverfacility => "LOG_USER";
}
Notes:
See syslog notes.
portType: int
Allowed input range: 1024,99999
Default value: 5308
Synopsis: Default port for cfengine server
Example:
body runagent control
{
port => "5308";
}
body server control
{
specialhost::
port => "5308";
!specialhost::
port => "5308";
}
Notes:
The standard or registered port number is tcp/5308. CFEngine does not presently use its registered udp port with the same number, but this could change in the future.
Changing the standard port number is not recommended practice. You should not do it without a good reason.
keycacheTTLType: int
Allowed input range: 0,99999999999
Default value: 24
Synopsis: Maximum number of hours to hold public keys in the cache
Example:
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
body server control
{
keycacheTTL => "24";
}
Notes:
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
monitor control promises
body monitor control()
{
#version => "1.2.3.4";
threshold => "0.3";
forgetrate => "0.7";
histograms => "true";
tcpdump => "false";
tcpdumpcommand => "/usr/sbin/tcpdump -i eth1 -n -t -v";
}
|
Settings describing the details of the fixed behavioural promises made by
cf-monitord.
The system defaults will be sufficient for most users. This
configurability potential, however, will be a key to developing the
integrated monitoring capabilities of cfengine.
forgetrateType: real
Allowed input range: 0,1
Default value: 0.6
Synopsis: Decimal fraction [0,1] weighting of new values over old in 2d-average computation
Example:
body monitor control
{
threshold => "0.3";
forgetrate => "0.7";
histograms => "true";
}
Notes:
Configurable settings for the machine-learning algorithm that tracks system behaviour. This is only for expert users. This parameter effectively determines (together with the monitoring rate) how quickly cfengine forgets its previous history.
monitorfacilityType: (menu option)
Allowed input range:
LOG_USERLOG_DAEMONLOG_LOCAL0LOG_LOCAL1LOG_LOCAL2LOG_LOCAL3LOG_LOCAL4LOG_LOCAL5LOG_LOCAL6LOG_LOCAL7
Default value: LOG_USER
Synopsis: Menu option for syslog facility
Example:
body monitor control
{
monitorfacility => "LOG_USER";
}
Notes:
See notes for syslog.
histogramsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: true
Synopsis: true/false store signal histogram data
Example:
body monitor control
{
histograms => "true";
}
Notes:
This is like the ‘-H’ option to cfenvd in cfengine 2. It
causes cfengine to learn the conformally transformed distributions of
fluctuations about the mean.
tcpdumpType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false use tcpdump if found
Example:
body monitor control
{
tcpdump => "true";
}
Notes:
Interface with TCP stream if possible.
tcpdumpcommandType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Path to the tcpdump command on this system
Example:
body monitor control
{
tcpdumpcommand => "/usr/sbin/tcpdump -i eth1";
}
Notes:
If this is defined, the monitor will try to interface with the TCP stream and monitor generic package categories for anomalies.
runagent control promises
body runagent control
{
# default port is 5308
hosts => { "127.0.0.1:5308", "eternity.iu.hio.no:80", "slogans.iu.hio.no" };
#output_to_file => "true";
}
|
Settings describing the details of the fixed behavioural promises made by
cf-runagent.
The most important parameter here is the list of hosts that the agent
will poll for connections. This is easily read in from a file list,
however when doing so always have a stable input source that does not
depend on the network (including a database or directory service) in
any way: introducing such dependencies makes configuration brittle.
hostsType: slist
Allowed input range: (arbitrary string)
Synopsis: List of host or IP addresses to attempt connection with
Example:
body runagent control
{
network1::
hosts => { "host1.example.org", "host2", "host3" };
network2::
hosts => { "host1.example.com", "host2", "host3" };
}
Notes:
The complete list of contactable hosts. The values may be either numerical IP addresses or DNS names, optionally suffixed by a ‘:’ and a port number. If no port number is given, the default cfengine port 5308 is assumed.
portType: int
Allowed input range: 1024,99999
Default value: 5308
Synopsis: Default port for cfengine server
Example:
body runagent control
{
port => "5308";
}
body server control
{
specialhost::
port => "5308";
!specialhost::
port => "5308";
}
Notes:
The standard or registered port number is tcp/5308. CFEngine does not presently use its registered udp port with the same number, but this could change in the future.
Changing the standard port number is not recommended practice. You should not do it without a good reason.
force_ipv4Type: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false force use of ipv4 in connection
Example:
body copy_from example
{
force_ipv4 => "true";
}
Notes:
IPv6 should be harmless to most users unless you have a partially or misconfigured setup.
trustkeyType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false automatically accept all keys on trust from servers
Example:
body copy_from example
{
trustkey => "true";
}
Notes:
If the server's public key has not already been trusted, this allows us to accept the key in automated key-exchange.
Note that, as a simple security precaution, trustkey should normally be set to ‘false’, to avoid key exchange with a server one is not one hundred percent sure about, though the risks for a client are rather low. On the server-side however, trust is often granted to many clients or to a whole network in which possibly unauthorized parties might be able to obtain an IP address, thus the trust issue is most important on the server side.
As soon as a public key has been exchanged, the trust option has no effect. A machine that has been trusted remains trusted until its key is manually revoked by a system administrator. Keys are stored in WORKDIR/ppkeys.
encryptType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false encrypt connections with servers
Example:
body copy_from example
{
servers => { "remote-host.example.org" };
encrypt => "true";
}
Notes:
Client connections are encrypted with using a Blowfish randomly generated session key. The intial connection is encrypted using the public/private keys for the client and server hosts.
background_childrenType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false parallelize connections to servers
Example:
body runagent control
{
background_children => "true";
}
Notes:
Causes the runagent to attempt parallelized connections to the servers.
max_childrenType: int
Allowed input range: 0,99999999999
Default value: 1 concurrent agent promise
Synopsis: Maximum number of simultaneous connections to attempt
Example:
body runagent control
{
max_children => "10";
}
# or
body agent control
{
max_children => "10";
}
Notes:
For the run-agent this represents the maximum number of forked background processes allowed when parallelizing connections to servers. For the agent it represents the number of background jobs allowed concurrently. Background jobs often lead to contention of the disk resources slowing down tasks considerably; there is thus a law of diminishing returns.
output_to_fileType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false whether to send collected output to file(s)
Example:
body runagent control
{
output_to_file => "true";
}
Notes:
Filenames are chosen automatically and placed in the WORKDIR/outputs/hostname_runagent.out.
timeoutType: int
Allowed input range: 1,9999
Synopsis: Connection timeout, sec
Example:
body agent control
{
timeout => "10";
}
Notes:
Timeout in seconds.
executor control promises
body executor control
{
splaytime => "5";
mailto => "cfengine@example.org";
mailfrom => "cfengine@$(host).example.org";
smtpserver => "localhost";
schedule => { "Min00_05", "Min30_35" }
}
|
These body settings determine the behaviour of cf-execd, including
scheduling times and output capture to WORKDIR/outputs and relay via email.
Note that the splaytime and schedule parameters
are now coded here rather than (as previously) in the agent.
splaytimeType: int
Allowed input range: 0,99999999999
Default value: 0
Synopsis: Time in minutes to splay this host based on its name hash
Example:
body executor control
{
splaytime => "2";
}
Notes:
Whenever any class listed in the schedule attribute is
present, cf-execd can schedule an execution of cf-agent. The
actual execution will be delayed an integer number of seconds between
0-splaytime minutes. The
specific amount of delay for “this” host is based on a hash of the
hostname. Thus a collection of hosts will all execute at different
times, and surges in network traffic can be avoided.
A rough rule of thumb for scaling of small updates is set the splay time by:
splaytime = 1 + Number of clients / 50
Default value:
The default value is 0 minutes.
See also: The splayclass() function for a task-specific
means for setting splay times.
mailfromType: string
Allowed input range: .*.*
Synopsis: Email-address cfengine mail appears to come from
Example:
body executor control
{
mailfrom => "MrCfengine@example.org";
}
Notes:
mailtoType: string
Allowed input range: .*.*
Synopsis: Email-address cfengine mail is sent to
Example:
body executor control
{
mailto => "cfengine_alias@example.org";
}
Notes:
The address to whom email is sent if an smtp host is configured.
smtpserverType: string
Allowed input range: .*
Synopsis: Name or IP of a willing smtp server for sending email
Example:
body executor control
{
smtpserver => "smtp.example.org";
}
Notes:
This should point to a standard port 25 server without encyption. If you are running secured or encrypted email then you should run a mail relay on localhost and point this to localhost.
mailmaxlinesType: int
Allowed input range: 0,1000
Default value: 30
Synopsis: Maximum number of lines of output to send by email
Example:
body executor control
{
mailmaxlines => "100";
}
Notes:
This limit prevents anomalously large outputs from clogging up a system administrator's mailbox. The output is truncated in the email report, but the complete original transcript is stored in WORKDIR/outputs/* where it can be viewed on demand. A reference to the appropriate file is given.
scheduleType: slist
Allowed input range: (arbitrary string)
Synopsis: The class schedule used by cf-execd for activating cf-agent
Example:
body executor control
{
schedule => { "Min00", "(Evening|Night).Min15_20", "Min30", "(Evening|Night).Min45_50" };
}
Notes:
The list should contain class expressions comprised of classes which are
visible to the cf-execd daemon. In principle, any defined class
expression will cause the daemon to wake up
and schedule the execution of the cf-agent. In practice, the classes
listed in the list are usually date- and time-based.
The actual execution of
cf-agent may be delayed by splaytime, and may be deferred by
promise caching and the value of ifelapsed. Note also that the
effectiveness of the splayclass function may be affected by changing
the schedule.
Default value:
schedule => { "Min00", "Min05", "Min10", "Min15", "Min20", "Min25",
"Min30", "Min35", "Min40", "Min45", "Min50", "Min55" };
executorfacilityType: (menu option)
Allowed input range:
LOG_USERLOG_DAEMONLOG_LOCAL0LOG_LOCAL1LOG_LOCAL2LOG_LOCAL3LOG_LOCAL4LOG_LOCAL5LOG_LOCAL6LOG_LOCAL7
Default value: LOG_USER
Synopsis: Menu option for syslog facility level
Example:
body executor control
{
executorfacility => "LOG_USER";
}
Notes:
See the syslog manual pages.
exec_commandType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: The full path and command to the executable run by default (overriding builtin)
Example:
exec_command => "$(sys.workdir)/bin/cf-agent -f failsafe.cf && $(sys.workdir)/bin/cf-agent";
Notes:
The command is run in a shell encapsulation so pipes and shell symbols may be used if desired. Unlike, cfengine 2, cfengine 3 does not automatically run a separate update sequence before its normal run. This can be handled using the approach in the example above.
knowledge control promises
body knowledge control
{
build_directory => ".";
sql_database => "my_knowledge";
sql_owner => "db_user";
sql_passwd => ""; # No passwd
sql_type => "mysql";
query_output => "html";
style_sheet => "http://www.example.org/css/style.css";
html_banner =>
"
<ul>
<li>Item 1
<li>Item 2
</ul>
";
}
|
Settings describing the details of the fixed behavioural promises made by
cf-know.
These parameters control the way in which knowledge data are stored
and retrieved from a relational database and the output format
of the queries.
build_directoryType: string
Allowed input range: .*
Default value: Current working directory
Synopsis: The directory in which to generate output files
Example:
body knowledge control
{
#..
build_directory => "/tmp/builddir";
}
body reporter control
{
#..
build_directory => "/tmp/builddir";
}
Notes:
The directory where all auto-generated textual output is placed by cf-know.
This includes manual generation, ontology and topic map data.
document_rootType: string
Allowed input range: .*
Synopsis: The directory in which the web root resides
Example:
body knowledge control
{
document_root => "/srv/www/htdocs";
}
Notes:
The local file path of the system's web document root.
generate_manualType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false generate texinfo manual page skeleton for this version
Example:
body knowledge control
{
generate_manual => "true";
}
Notes:
Auto-creates a manual based on the self-documented code. As the promise syntax is extended the manual self-heals. The resulting manual is generated in Texinfo format, from which all other formats can be generated.
graph_directoryType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Path to directory where rendered .png files will be created
Example:
body knowledge control
{
graph_directory => "/tmp/output";
}
Notes:
A separate location where the potentially large number of .png visualizations of a knowledge representation are pre-compiled. This feature only works if the necessary graphics libraries are present.
graph_outputType: (menu option)
Allowed input range:
truefalseyesnoonoff
Synopsis: true/false generate png visualization of topic map if possible (requires lib)
Example:
body knowledge control
{
# fix/override -g option
graph_output => "true";
}
Notes:
Equivalent to the use of the ‘-g’ option for cf-know.
html_bannerType: string
Allowed input range: (arbitrary string)
Synopsis: HTML code for a banner to be added to rendered in html after the header
Example:
body knowledge control
{
html_banner => "<img src=\"http://www.example.org/img/banner.png\">";
}
body reporter control
{
html_banner => "<img src=\"http://www.example.org/img/banner.png\">";
}
Notes:
This content is cited when generating HTML output from the knowledge agent.
html_footerType: string
Allowed input range: (arbitrary string)
Synopsis: HTML code for a page footer to be added to rendered in html before the end body tag
Example:
body reporter control
{
html_footer => "
<div id=\"footer\">Bottom of the page</div>
";
}
body knowledge control
{
html_footer => "
<div id=\"footer\">Bottom of the page</div>
";
}
Notes:
This allows us to cite HTML code for formatting reports generated by the reporting and knowledge agents.
id_prefixType: string
Allowed input range: .*
Synopsis: The LTM identifier prefix used to label topic maps (used for disambiguation in merging)
Example:
body knowledge control
{
id_prefix => "unique_prefix";
}
Notes:
Use to disambiguate indentifiers for a successful merging of topic maps, especially in Linear Topic Map (LTM) format using third party tools such as Ontopia's Omnigator.
manual_source_directoryType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Path to directory where raw text about manual topics is found (defaults to build_directory)
Example:
body knowledge control
{
manual_source => "/path/cfengine_manual_commentary";
}
Notes:
This is used in the self-healing documentation. The directory points to a location where the Texinfo sources for per-section commentary is maintained.
query_engineType: string
Allowed input range: (arbitrary string)
Synopsis: Name of a dynamic web-page used to accept and drive queries in a browser
Example:
body knowledge control
{
query_engine => "http://www.example.org/script.php";
}
body reporter control
{
query_engine => "http://www.example.org/script.pl";
}
Notes:
When displaying topic maps in HTML format, cf-know will render
each topic as a link to this URL with the new topic as an argument.
Thus it is possible to make a dynamic web query by embedding cfengine
in the web page as system call and passing the argument to it.
query_outputType: (menu option)
Allowed input range:
htmltext
Synopsis: Menu option for generated output format
Example:
body knowledge control
{
query_output => "html";
}
Notes:
sql_typeType: (menu option)
Allowed input range:
mysqlpostgres
Synopsis: Menu option for supported database type
Example:
body knowledge control
{
sql_type => "mysql";
}
Notes:
sql_databaseType: string
Allowed input range: (arbitrary string)
Synopsis: Name of database used for the topic map
Example:
body knowledge control
{
sql_database => "cfengine_knowledge_db";
}
Notes:
The name of an SQL database for caching knowledge.
sql_ownerType: string
Allowed input range: (arbitrary string)
Synopsis: User id of sql database user
Example:
body knowledge control
{
sql_owner => "db_owner";
}
Notes:
Part of the credentials for opening the database. This depends on the type of database.
sql_passwdType: string
Allowed input range: (arbitrary string)
Synopsis: Embedded password for accessing sql database
Example:
body knowledge control
{
sql_passwd => "";
}
Notes:
Part of the credentials for connecting to the database server. This is system dependent. If the server host is localhost a password might not be required.
sql_serverType: string
Allowed input range: (arbitrary string)
Synopsis: Name or IP of database server (or localhost)
Example:
body knowledge control
{
sql_server => "localhost";
}
Notes:
The host name of IP address of the server. The default is to look on the localhost.
sql_connection_dbType: string
Allowed input range: (arbitrary string)
Synopsis: The name of an existing database to connect to in order to create/manage other databases
Example:
body knowledge control
{
sql_connection_db => "mysql";
}
Notes:
In order to create a database on a database server (all of which
practice voluntary cooperation), one has to be able to connect
to the server, however, without an existing database this is not allowed.
Thus, database servers provide a default database that can be connected
to in order to thereafter create new databases. These are called
postgres and mysql for their respective database servers.
For the knowledge agent, this setting is made in the control body,
for database verification promises, it is made in the
database_server body.
style_sheetType: string
Allowed input range: (arbitrary string)
Synopsis: Name of a style-sheet to be used in rendering html output (added to headers)
Example:
body knowledge control
{
style_sheet => "http://www.example.org/css/sheet.css";
}
body reporter control
{
style_sheet => "http://www.example.org/css/sheet.css";
}
Notes:
For formatting the HTML generated output of cf-know.
view_projectionsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: Perform view-projection analytics in graph generation
Example:
body knowledge control
{
view_projections => "true";
}
Notes:
If this is set to true, CFEngine Nova computes additional graphical representations in its knowledge map, representing causal dependencies between CFEngine promises.
reporter control promises
body reporter control
{
reports => { "performance", "last_seen", "monitor_history" };
build_directory => "/tmp/nerves";
report_output => "html";
}
Determines a list of reports to write into the build directory. The
format may be in text, html or xml format. The reporter agent
cf-report replaces both cfshow and cfenvgraph. It
no longer produces output to the console.
Some reports are only available in enterprise level versions of cfengine.
aggregation_pointType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: The root directory of the data cache for CMDB aggregation
Example:
body reporter control
{
aggregation_point => "/srv/www/htdocs/reports";
}
Notes:
This feature is only used in enterprise level versions of cfengine. It specifies the directory where reports from multiple hosts are to be aggregated in sub-directories. This should be somewhere under the document root of the web server for the cfengine knowledge base in order to make the reports browsable.
auto_scalingType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: true
Synopsis: true/false whether to auto-scale graph output to optimize use of space
Example:
body reporter control
{
auto_scaling => "true";
}
Notes:
Automatic scaling is the default.
build_directoryType: string
Allowed input range: .*
Default value: Current working directory
Synopsis: The directory in which to generate output files
Example:
body knowledge control
{
#..
build_directory => "/tmp/builddir";
}
body reporter control
{
#..
build_directory => "/tmp/builddir";
}
Notes:
The directory where all auto-generated textual output is placed by cf-know.
This includes manual generation, ontology and topic map data.
csv2xmlType: slist
Allowed input range: (arbitrary string)
Synopsis: A list of csv formatted files in the build directory to convert to simple xml
Example:
body reporter control
{
csv2xml => { "myreport.csv", "custom_report.csv" };
}
Notes:
CSV files are easy to generate in cfengine from individual promise logging functions.
XML is not easily generated due to its hierarchical structure. This function allows
cf-report to convert a CSV file into pidgin XML for convenience. The schema
has the general form:
<output> <line> <one>...</one> <two>...</two> ... </line> <line> <one>...</one> <two>...</two> ... </line> </output>
error_barsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: true
Synopsis: true/false whether to generate error bars on graph output
Example:
body reporter control
{
error_bars => "true";
}
Notes:
The default is to produce error bars. Without error bars from cfengine's machine learning data there is no way to assess the significance of an observation about the system, i.e. whether it is normal or anomalous.
html_bannerType: string
Allowed input range: (arbitrary string)
Synopsis: HTML code for a banner to be added to rendered in html after the header
Example:
body knowledge control
{
html_banner => "<img src=\"http://www.example.org/img/banner.png\">";
}
body reporter control
{
html_banner => "<img src=\"http://www.example.org/img/banner.png\">";
}
Notes:
This content is cited when generating HTML output from the knowledge agent.
html_embedType: (menu option)
Allowed input range:
truefalseyesnoonoff
Synopsis: If true, no header and footer tags will be added to html output
Example:
body reporter control
{
html_embed => "true";
}
Notes:
Embedded HTML means something that could be put into a frame or table, without html or body tags, headers footers etc.
html_footerType: string
Allowed input range: (arbitrary string)
Synopsis: HTML code for a page footer to be added to rendered in html before the end body tag
Example:
body reporter control
{
html_footer => "
<div id=\"footer\">Bottom of the page</div>
";
}
body knowledge control
{
html_footer => "
<div id=\"footer\">Bottom of the page</div>
";
}
Notes:
This allows us to cite HTML code for formatting reports generated by the reporting and knowledge agents.
query_engineType: string
Allowed input range: (arbitrary string)
Synopsis: Name of a dynamic web-page used to accept and drive queries in a browser
Example:
body knowledge control
{
query_engine => "http://www.example.org/script.php";
}
body reporter control
{
query_engine => "http://www.example.org/script.pl";
}
Notes:
When displaying topic maps in HTML format, cf-know will render
each topic as a link to this URL with the new topic as an argument.
Thus it is possible to make a dynamic web query by embedding cfengine
in the web page as system call and passing the argument to it.
reportsType: (option list)
Allowed input range:
allauditperformanceall_locksactive_lockshashesclasseslast_seenmonitor_nowmonitor_historymonitor_summarycompliancesetuidfile_changesinstalled_softwaresoftware_patchesvaluevariables
Default value: none
Synopsis: A list of reports that may be generated
Example:
body reporter control
{
reports => { "performance", "classes" };
}
Notes:
A list of report types that can be generated by this agent. The
listed items from compliance onward are available only
Enterprise editions of cfengine.
The keyword ‘all’ can be used to get all reports except the audit and locking reports. The latter are large and unwieldy and need specific confirmation.
report_outputType: (menu option)
Allowed input range:
csvhtmltextxml
Default value: none
Synopsis: Menu option for generated output format. Applies only to text reports, graph data remain in xydy format.
Example:
body reporter control
{
report_output => "html";
}
Notes:
Sets the output format of embedded database reports.
style_sheetType: string
Allowed input range: (arbitrary string)
Synopsis: Name of a style-sheet to be used in rendering html output (added to headers)
Example:
body knowledge control
{
style_sheet => "http://www.example.org/css/sheet.css";
}
body reporter control
{
style_sheet => "http://www.example.org/css/sheet.css";
}
Notes:
For formatting the HTML generated output of cf-know.
time_stampsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false whether to generate timestamps in the output directory name
Example:
body reporter control
{
time_stamps => "true";
}
Notes:
This option is only necessary with the default build directory. This can be used to keep snapshots of the system but it will result in a lot of storage be consumed. For most purposes cfengine is programmed to forget the past at a predictable rate and there is no need to override this.
hub control promises
body hub control
{
export_zenoss => "true";
}
export_zenossType: (menu option)
Allowed input range:
truefalseyesnoonoff
Synopsis: Make data available for Zenoss integration in docroot/reports/summary.z
Example:
body hub control
{
am_policy_hub::
export_zenoss => "true";
}
Notes:
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
For integration with the Zenoss monitoring software.
hub_scheduleType: slist
Allowed input range: (arbitrary string)
Synopsis: The class schedule used by cf-hub for report collation
Example:
body hub control
{
hub_schedule => { "Min00", "Min30", "(Evening|Night).Min45_50" };
}
Notes:
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
common
bundle common globals
{
vars:
"global_var" string => "value";
classes:
"global_class" expression => "value";
}
|
Common bundles may only contain the promise types that are common to all bodies. Their main function is to define cross-component global definitions. Common bundles are observed by every agent, whereas the agent specific bundle types are ignored by components other than the intended recipient.
vars promises
Whereas most promise types are specific to a particular kind of
interpretation that requires a typed interpreter (the bundle type),
a number of promises can be made in any kind of bundle since they
are of a generic input/output nature. These are vars, classes,
and reports promises. The specific promise attributes are listed below.
stringType: string
Allowed input range: (arbitrary string)
Synopsis: A scalar string
Example:
vars: "xxx" string => "Some literal string..."; "yyy" string => readfile( "/home/mark/tmp/testfile" , "33" );
Notes:
In cfengine previously lists were represented (as in the shell) using separted scalars, e.g. like the PATH variable. This design feature turned out to be an error of judgement which has resulted in much trouble. This is no longer supported in cfengine 3. By keeping lists an independent type many limitations have been removed.
intType: int
Allowed input range: -99999999999,9999999999
Synopsis: A scalar integer
Example:
vars:
"scalar" int => "16k";
"ran" int => randomint(4,88);
"dim_array" int => readstringarray("array_name","/etc/passwd","#[^\n]*",":",10,4000);
Notes:
Int variables are strings that are expected to be used as integer numbers. The
typing in cfengine is dynamic, so the variable types are interchangable, but
when you declare a variable to be type int, CFEngine verifies that
the value you assign to it looks like an integer (e.g., ‘3’,
‘-17’, ‘16K’, etc).
Integer values may use suffices ‘k’, ‘K’, ‘m’, ‘M’, etc., but must only have an integer numeric part (so ‘1.5M’ is not allowed).
The value ‘inf’ may also be used to represent an unlimited positive value.
realType: real
Allowed input range: -9.99999E100,9.99999E100
Synopsis: A scalar real number
Example:
vars: "scalar" real => "0.5";
Notes:
Real variables are strings that are expected to be used as real numbers. The
typing in cfengine is dynamic, so the variable types are interchangable, but
when you declare a variable to be type real, CFEngine verifies that
the value you assign to it looks like a real number (e.g., ‘3’,
‘3.1415’, ‘.17’, ‘6.02e23’, ‘-9.21e-17’, etc).
Real numbers are not used in many places in cfengine, but they are useful for representing probabilties and performance data.
slistType: slist
Allowed input range: (arbitrary string)
Synopsis: A list of scalar strings
Example:
vars:
"xxx" slist => { "literal1", "literal2" };
"yyy" slist => {
readstringlist(
"/home/mark/tmp/testlist",
"#[a-zA-Z0-9 ]*",
"[^a-zA-Z0-9]",
15,
4000
)
};
"zzz" slist => { readstringlist("/home/mark/tmp/testlist2","#[^\n]*",",",5,4000) };
Notes:
Some functions return slists (see Introduction to functions),
and an slist may contain the values copied from another slist,
rlist, or ilist (see List variable substitution and expansion,
see policy in vars).
ilistType: ilist
Allowed input range: -99999999999,9999999999
Synopsis: A list of integers
Example:
vars:
"variable_id"
ilist => { "10", "11", "12" };
Notes:
Integer lists are lists of strings that are expected to be treated as integers.
The typing in cfengine is dynamic, so the variable types are interchangable,
but when you declare a variable to be type ilist, CFEngine verifies that
each value you assign to it looks like an integer (e.g., ‘3’,
‘-17’, ‘16K’, etc).
Some functions return ilists (see Introduction to functions),
and an ilist may contain the values copied from another slist,
rlist, or ilist (see List variable substitution and expansion,
see policy in vars).
rlistType: rlist
Allowed input range: -9.99999E100,9.99999E100
Synopsis: A list of real numbers
Example:
vars:
"varid" rlist => { "0.1", "0.2", "0.3" };
Notes:
Real lists are lists of strings that are expected to be used as real numbers.
The typing in cfengine is dynamic, so the variable types are interchangable,
but when you declare a variable to be type rlist, CFEngine verifies that
each value you assign to it looks like a real number (e.g., ‘3’,
‘3.1415’, ‘.17’, ‘6.02e23’, ‘-9.21e-17’, etc).
Some functions return rlists (see Introduction to functions),
and an rlist may contain the values copied from another slist,
rlist, or ilist (see List variable substitution and expansion,
see policy in vars).
policyType: (menu option)
Allowed input range:
freeoverridableconstantifdefined
Synopsis: The policy for (dis)allowing (re)definition of variables
Example:
vars:
"varid" string => "value...",
policy => "constant";
Notes:
Variables can either be allowed to change their value dynamically (be redefined) or they can be constant. The use of private variable spaces in cfengine 3 makes it unlikely that variable redefinition would be necessary in cfengine 3.
The value constant indicates that the variable value may not be
changed. The values free and overridable are synonymous, and
indicated the the variable's value may be changed.
The value ifdefined applies only to lists and implies that unexpanded
or undefined lists are dropped. The default behaviour is otherwise to
retain this value as an indicator of the failure to quench the variable
reference, e.g.
"one" slist => { "1", "2", "3" };
"list" slist => { "@(one)", @(two) },
policy => "ifdefined";
would result in ‘@(list)’ being the same as ‘@(one)’,
and the reference to ‘@(two)’ would disappear. This is useful for combining
lists, `inheritance-style' where one can extend a base with special cases if they
are defined.
Default value:
policy => constant
classes promises
Whereas most promise types are specific to a particular kind of
interpretation that requires a typed interpreter (the bundle type),
a number of promises can be made in any kind of bundle since they
are of a generic input/output nature. These are vars, classes,
and reports promises. The specific promise attributes are listed below.
orType: clist
Allowed input range: [a-zA-Z0-9_!&@$|.()]+
Synopsis: Combine class sources with inclusive OR
Example:
classes:
"compound_test"
or => { classmatch("linux_x86_64_2_6_22.*"), "suse_10_3" };
Notes:
A useful construction for writing expressions that contain special functions. The class in the LHS will be defined if any one (or more) of the class expressions in the RHS are true.
andType: clist
Allowed input range: [a-zA-Z0-9_!&@$|.()]+
Synopsis: Combine class sources with AND
Example:
classes:
"compound_class" and => { classmatch("host[0-9].*"), "Monday", "Hr02" };
Notes:
If an expression contains a mixture of different object types that need to be ANDed together, this list form is more convenient than providing an expression. If all of the class expressions listed in the RHS match, then the class on the LHS is defined.
xorType: clist
Allowed input range: [a-zA-Z0-9_!&@$|.()]+
Synopsis: Combine class sources with XOR
Example:
classes:
"another_global" xor => { "any", "linux", "solaris"};
Notes:
If exactly one of the class expressions in the RHS matches, then the class on
the LHS is defined.
distType: rlist
Allowed input range: -9.99999E100,9.99999E100
Synopsis: Generate a probabilistic class distribution (strategy in cfengine 2)
Example:
classes:
"my_dist"
dist => { "10", "20", "40", "50" };
Notes:
Assign one generic class (always) and one additional class, randomly weighted
on a probability distribution. The sum of 10+20+40+50 = 120 in the
example above, so in generating a distribution, cfengine picks a number
between 1-120. This will generate the following classes:
my_dist (always)
my_dist_10 (10/120 of the time)
my_dist_20 (20/120 of the time)
my_dist_40 (40/120 of the time)
my_dist_50 (50/120 of the time)
This was previous called a ‘strategy’ in cfengine 2.
expressionType: class
Allowed input range: [a-zA-Z0-9_!&@$|.()]+
Synopsis: Evaluate string expression of classes in normal form
Example:
classes:
"class_name" expression => "solaris|(linux.specialclass)";
"has_toor" expression => userexists("toor");
Notes:
A way of aliasing class combinations.
notType: class
Allowed input range: [a-zA-Z0-9_!&@$|.()]+
Synopsis: Evaluate the negation of string expression in normal form
Example:
classes:
"others" not => "linux|solaris";
"no_toor" not => userexists("toor");
Notes:
This negates the effect of the promiser-pattern regular expression. The class in the LHS will only be defined if the class expression in the RHS is false.
reports promises
Whereas most promise types are specific to a particular kind of
interpretation that requires a typed interpreter (the bundle type),
a number of promises can be made in any kind of bundle since they
are of a generic input/output nature. These are vars, classes,
and reports promises. The specific promise attributes are listed below.
friend_patternType: string
Allowed input range: (arbitrary string)
Synopsis: Regular expression to keep selected hosts from the friends report list
Example:
reports:
linux::
"Friend status report"
lastseen => "0"
friend_pattern => "host1|host2|.*\.domain\.tld";
Notes:
This regular expression should match hosts we want to exclude from friend reports.
intermittencyType: real
Allowed input range: 0,1
Default value: false
Synopsis: Real number threshold [0,1] of intermittency about current peers, report above
Example:
reports:
"Comment"
intermittency => "0.5";
Notes:
Report on cfengine peers in the neighbourhood watch whose observed irregularity of connection exceeds 0.5 scaled entropy units, meaning that they show an erratic pattern of connection.
lastseenType: int
Allowed input range: 0,99999999999
Synopsis: Integer time threshold in hours since current peers were last seen, report absence
Example:
In control:
body agent control
{
lastseen => "false";
}
See also in reports:
reports:
"Comment"
lastseen => "10";
Notes:
In reports: after this time (hours) has passed, cfengine will begin to
warn about the host being overdue. After the lastseenexpireafter expiry time, hosts
will be purged from this host's database (default is a week).
In control: determines whether cfengine will records last seen intermittency profiles (reliability diagnostics) in WORKDIR/lastseen. This generates a separate file for each each host that connects to the current host. For central hubs this can result is a huge number of files.
printfile (compound body)Type: (ext body)
file_to_print’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Path name to the file that is to be sent to standard output
Example:
body printfile example
{
file_to_print => "/etc/motd";
number_of_lines => "10";
}
Notes:
Include part of a file in a report.
number_of_lines’Allowed input range: 0,99999999999
Synopsis: Integer maximum number of lines to print from selected file
Example:
body printfile example
{
number_of_lines => "10";
}
Notes:
report_to_fileType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: The path and filename to which output should be appended
Example:
bundle agent test
{
reports:
linux::
"$(sys.date),This is a report from $(sys.host)"
report_to_file => "/tmp/test_log";
}
Notes:
Append the output of the report to the named file instead of standard output. If the file cannot be opened for writing then the report defaults to the standard output.
showstateType: slist
Allowed input range: (arbitrary string)
Synopsis: List of services about which status reports should be reported to standard output
Example:
reports:
"Comment"
showstate => {"www_in", "ssh_out", "otherprocs" };
Notes:
The basic list of services is:
* promises
Whereas most promise types are specific to a particular kind of
interpretation that requires a typed interpreter (the bundle type),
a number of promises can be made in any kind of bundle since they
are of a generic input/output nature. These are vars, classes,
and reports promises. The specific promise attributes are listed below.
action (compound body)Type: (ext body)
action_policy’Allowed input range:
fixwarnnop
Synopsis: Whether to repair or report about non-kept promises
Example:
The following example shows a simple use of transaction control, causing the promise to be verified as a separate background process.
body action background
{
action_policy => "warn";
}
Notes:
The action settings allow general transaction control to be
implemented on promise verification. Action bodies place limits on how
often to verify the promise and what classes to raise in the case that
the promise can or cannot be kept.
Note that actions can be added to sub-bundles like methods and editing bundles, and that promises within these do not inherit action settings at higher levels. Thus, in the following example there are two levels of action setting:
########################################################
#
# Warn if line matched
#
########################################################
body common control
{
bundlesequence => { "testbundle" };
}
########################################################
bundle agent testbundle
{
files:
"/var/cfengine/inputs/.*"
edit_line => DeleteLinesMatching(".*cfenvd.*"),
action => WarnOnly;
}
########################################################
bundle edit_line DeleteLinesMatching(regex)
{
delete_lines:
"$(regex)" action => WarnOnly;
}
########################################################
body action WarnOnly
{
action_policy => "warn";
}
The action setting for the files promise means that file
edits will not be committed to disk, only warned about. This is a master-level
promise that overrides anything that happens during the editing. The
action setting for the edit bundle means that the internal
memory modelling of the file will only warn about changes rather than
committing them to the memory model. This makes little difference to the
end result, but it means that cfengine will report
Need to delete line - ... - but only a warning was promised
Instead of
Deleting the prpomised line ...
Need to save file - but only a warning was promised
In either case, no changes will be made to the disk, but the messages
given by cf-agent will differ.
ifelapsed’Allowed input range: 0,99999999999
Synopsis: Number of minutes before next allowed assessment of promise
Default value: 1
Example:
#local
body action example
{
ifelapsed => "120"; # 2 hours
expireafter => "240"; # 4 hours
}
# global
body agent control
{
ifelapsed => "180"; # 3 hours
}
Notes:
This overrides the global settings. Promises which take a long time to
verify should usually be protected with a long value for this
parameter. This serves as a resource `spam' protection. A cfengine
check could easily run every 5 minutes provided resource intensive
operations are not performed on every run. Using time classes like
Hr12 etc., is one part of this strategy; using ifelapsed
is another which is not tied to a specific time.
expireafter’Allowed input range: 0,99999999999
Synopsis: Number of minutes before a repair action is interrupted and retried
Default value: 1 min
Example:
body action example
{
ifelapsed => "120"; # 2 hours
expireafter => "240"; # 4 hours
}
Notes:
The locking time after which cfengine will attempt to kill and restart
its attempt to keep a promise.
log_string’Allowed input range: (arbitrary string)
Synopsis: A message to be written to the log when a promise verification leads to a repair
Example:
promise-type:
"promiser"
attr => "value",
action => log_me("checked $(this.promiser) in promise $(this.handle)");
# ..
body action log_me(s)
{
log_string => "$(s)";
}
Notes:
The log_string works together with log_repair,
log_kept etc, to define a string for logging to one of the named
files depending on promise outcome, or to standard output of the log file
is stipulared as ‘stdout’. Log strings on standard output are denoted
by an ‘L:’ prefix.
Note that log_string does not interact with log_level,
which is about regular system output messages.
Hint: the promise handle ‘$(this.handle)’ can be a useful
referent in a log message, indicating the origin of the message. In
CFEngine Nova and above, every promise has a default handle (which is based o
the filename and line number - specifying your own handle will probably be
more mnemonic)..
log_level’Allowed input range:
informverboseerrorlog
Synopsis: The reporting level sent to syslog
Example:
body action example
{
log_level => "inform";
}
Notes:
Use this as an alternative to auditing to use the syslog mechanism to centralize
or manage messaging from cfengine. A backup of these messages will still be
kept in WORKDIR/outputs if you are using cf-execd.
On native Windows version of CFEngine (Nova or above), using
‘verbose’ will include a message when the promise is kept or
repaired in the event log.
log_kept’Allowed input range: stdout|udp_syslog|("?[a-zA-Z]:\\.*)|(/.*)
Synopsis: This should be filename of a file to which log_string will be saved, if undefined it goes to the system logger
Example:
body action logme(x)
{
log_kept => "/tmp/private_keptlog.log";
log_failed => "/tmp/private_faillog.log";
log_repaired => "/tmp/private_replog.log";
log_string => "$(sys.date) $(x) promise status";
}
Notes:
If this option is specified together with log_string, the
current promise will log promise-kept status using the log string to
this named file. If these log names are absent, the default logging
destination for the log string is syslog, but only for non-kept
promises. Only the log_string is affected by this setting. Other messages
destined for logging are sent to syslog.
It is intended that named file logs should be different for the three cases: promise kept, promise not kept and promise repaired.
This string should be the full path to a text file which will contain the log, of one of the following special values:
syslog_server defined in ‘body common control’ and log the message there,
assuming the server is configured to receive the request.
log_priority’Allowed input range:
emergencyalertcriticalerrorwarningnoticeinfodebug
Synopsis: The priority level of the log message, as interpreted by a syslog server
Example:
body action low_priority
{
log_priority => "info";
}
Notes:
This determines the importance of messages from CFEngine.
log_repaired’Allowed input range: stdout|udp_syslog|("?[a-zA-Z]:\\.*)|(/.*)
Synopsis: This should be filename of a file to which log_string will be saved, if undefined it goes to the system logger
Example:
bundle agent test
{
vars:
"software" slist => { "/root/xyz", "/tmp/xyz" };
files:
"$(software)"
create => "true",
action => logme("$(software)");
}
body action logme(x)
{
log_kept => "/tmp/private_keptlog.log";
log_failed => "/tmp/private_faillog.log";
log_repaired => "/tmp/private_replog.log";
log_string => "$(sys.date) $(x) promise status";
}
body action immediate_syslog(x)
{
log_repaired => "udp_syslog"; # Nova and above
log_string => "cfengine repaired promise $(this.handle) - $(x)";
}
Notes:
This may be the name of a log to which the log_string is written if a promise is repaired.
It should be the full path to a text file which will contain the log, of one of the following special
values:
syslog_server defined in ‘body common control’ and log the message there,
assuming the server is configured to receive the request.
log_failed’Allowed input range: stdout|udp_syslog|("?[a-zA-Z]:\\.*)|(/.*)
Synopsis: This should be filename of a file to which log_string will be saved, if undefined it goes to the system logger
Example:
bundle agent test
{
vars:
"software" slist => { "/root/xyz", "/tmp/xyz" };
files:
"$(software)"
create => "true",
action => logme("$(software)");
}
body action logme(x)
{
log_kept => "/tmp/private_keptlog.log";
log_failed => "/tmp/private_faillog.log";
log_repaired => "/tmp/private_replog.log";
log_string => "$(sys.date) $(x) promise status";
}
Notes:
If this option is specified together with log_string, the
current promise will log promise-kept status using the log string to
this named file. If these log names are absent, the default logging
destination for the log string is syslog, but only for non-kept
promises. Only the log_string is affected by this setting. Other messages
destined for logging are sent to syslog.
It is intended that named file logs should be different for the three cases: promise kept, promise not kept and promise repaired. This string should be the full path to a text file which will contain the log, of one of the following special values:
syslog_server defined in ‘body common control’ and log the message there,
assuming the server is configured to receive the request.
value_kept’Allowed input range: (arbitrary string)
Synopsis: A real number value attributed to keeping this promise
Example:
body transaction mydef
{
value_kept => "4.5"; # this promise is worth 4.5 dollars per hour
value_repaired => "2.5"; # fixing this promise is worth 2.5 dollars per hour
value_notkept => "-10.0"; # not keeping this promise costs is 10 dollars per hour
ifelapsed => "60"; # one hour
}
Notes:
If nothing is specified, the default value is +1.0.
However, nothing is logged unless the agent control body switched on
‘track_value => "true"’.
value_repaired’Allowed input range: (arbitrary string)
Synopsis: A real number value attributed to reparing this promise
Example:
body transaction mydef
{
value_kept => "4.5"; # this promise is worth 4.5 dollars per hour
value_repaired => "2.5"; # fixing this promise is worth 2.5 dollars per hour
value_notkept => "-10.0"; # not keeping this promise costs is 10 dollars per hour
ifelapsed => "60"; # one hour
}
Notes:
If nothing is specified, the default value is 0.5.
However, nothing is logged unless the agent control body switched on
‘track_value => "true"’.
value_notkept’Allowed input range: (arbitrary string)
Synopsis: A real number value (possibly negative) attributed to not keeping this promise
Example:
body transaction mydef
{
value_kept => "4.5"; # this promise is worth 4.5 dollars per hour
value_repaired => "2.5"; # fixing this promise is worth 2.5 dollars per hour
value_notkept => "-10.0"; # not keeping this promise costs is 10 dollars per hour
ifelapsed => "60"; # one hour
}
Notes:
If nothing is specified, the default value is -1.0.
However, nothing is logged unless the agent control body switched on
‘track_value => "true"’.
audit’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false switch for detailed audit records of this promise
Default value: false
Example:
body action example
{
# ...
audit => "true";
}
Notes:
If this is set, cfengine will perform auditing on this specific
promise. This means that all details surrounding the verification of
the current promise will be recorded in the audit database. The
database may be inspected with cf-report, or cfshow in
cfengine 2.
background’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false switch for parallelizing the promise repair
Default value: false
Example:
body action example
{
background => "true";
}
Notes:
If possible, perform the verification of the current promise in the background. This is advantageous only if the verification might take a significant amount of time, e.g. in remote copying of filesystem/disk scans.
On the windows version of CFEngine Nova, this can be useful if we
don't want to wait for a particular command to finish execution before
checking the next promise. This is particular for the windows platform
because there is no way that a program can start itself in the
background here (i.e. fork off a child process). However, file
operations can not be performed in the background on windows.
report_level’Allowed input range:
informverboseerrorlog
Synopsis: The reporting level for standard output
Default value: (none)
Example:
body action example
{
report_level => "verbose";
}
Notes:
In cfengine 2 one would say ‘inform=true’ or ‘syslog=true’, etc.
This replaces these levels since they act as encapsulating super-sets.
measurement_class’Allowed input range: (arbitrary string)
Synopsis: If set performance will be measured and recorded under this identifier
Example:
body action measure
{
measurement_class => "$(this.promiser) long job scan of /usr";
}
Notes:
By setting this string you switch on performance measurement for the current promise, and also give the measurement a name. The identifier forms a partial identity for optional performance scanning of promises of the form:
ID:promise-type:promiser.
These can be seen identifying using cf-reports, e.g. in the
generated file performance.html.
classes (compound body)Type: (ext body)
promise_repaired’Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of classes to be defined globally
Example:
body classes example
{
promise_repaired => { "change_happened" };
}
Notes:
If a promise is `repaired' it means that a corrective action had to be taken to keep the promise.
Important: complex promises, e.g. files promises that set
multiple parameters on a file simultaneously can report misleadingly.
The classes for different parts of a promise are not separable. Thus,
if you promise to create and file and change its permissions, when the
file exists with incorrect permissions, cf-agent will report
that the ‘promise_kept’ for the file existence, but
‘promise_repaired’ for the permissions. If you need separate
reports, you should code two separate promises rather than `overloading'
a single one.
repair_failed’Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of classes to be defined globally
Example:
body classes example
{
repair_failed => { "unknown_error" };
}
Notes:
A promise could not be repaired because the corrective
action failed for some reason.
repair_denied’Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of classes to be defined globally
Example:
body classes example
{
repair_denied => { "permission_failure" };
}
Notes:
A promise could not be kept because access to a key resource
was denied.
repair_timeout’Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of classes to be defined globally
Example:
body classes example
{
repair_timeout => { "too_slow", "did_not_wait" };
}
Notes:
A promise maintenance repair timed-out waiting for some dependent resource.
promise_kept’Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of classes to be defined globally
Example:
body classes example
{
promise_kept => { "success", "kaplah" };
}
Notes:
This class is set if no action was necessary by cf-agent
because the promise concerned was aready kept without further action
required.
Important: complex promises, e.g. files promises that set
multiple parameters on a file simultaneously can report misleadingly.
The classes for different parts of a promise are not separable. Thus,
if you promise to create and file and change its permissions, when the
file exists with incorrect permissions, cf-agent will report
that the ‘promise_kept’ for the file existence, but
‘promise_repaired’ for the permissions. If you need separate
reports, you should code two separate promises rather than `overloading'
a single one.
cancel_kept’Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of classes to be cancelled if the promise is kept
Example:
body classes example
{
cancel_kept => { "success", "kaplah" };
}
Notes:
If the promise was already kept and nothing was done, cancel (undefine) any of the listed classes so that they are no longer defined.
History: This attribute was introduced in CFEngine version 3.0.4 (2010)
cancel_repaired’Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of classes to be cancelled if the promise is repaired
Example:
body classes example
{
cancel_repaired => { "change_happened" };
}
Notes:
If the promise was repaired and changes were made to the system, cancel (undefine) any of the listed classes so that they are no longer defined.
History: This attribute was introduced in CFEngine version 3.0.4 (2010)
cancel_notkept’Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of classes to be cancelled if the promise is not kept for any reason
Example:
body classes example
{
cancel_notkept => { "failure" };
}
Notes:
If the promise was not kept but nothing could be done, cancel (undefine) any of the listed classes so that they are no longer defined.
History: This attribute was introduced in CFEngine version 3.0.4 (2010)
persist_time’Allowed input range: 0,99999999999
Synopsis: A number of minutes the specified classes should remain active
Example:
body classes example
{
persist_time => "10";
}
Notes:
By default classes are ephemeral entities that disappear when cf-agent
terminates. By setting a persistence time, they can last even when the agent
is not running.
timer_policy’Allowed input range:
absolutereset
Synopsis: Whether a persistent class restarts its counter when rediscovered
Default value: reset
Example:
body classes example
{
timer_policy => "reset";
}
Notes:
The in most cases resetting a timer will give a more honest appraisal of which classes are currently important, but if we want to activate a response of limited duration as a rare event then an asbolute time limit is useful.
ifvarclassType: string
Allowed input range: (arbitrary string)
Synopsis: Extended classes ANDed with context
Example:
The generic example has the form:
promise-type:
"promiser"
ifvarclass => "$(program)_running|($(program)_notfound&Hr12)";
A specific example would be:
bundle agent example
{
commands:
any::
"/bin/echo This is linux"
ifvarclass => "linux";
"/bin/echo This is solaris"
ifvarclass => "solaris";
}
Notes:
This is an additional class expression that will be evaluated after the ‘class::’ classes have selected promises. It is provided in order to enable a channel between variables and classes. The result is thus the logical AND of the ordinary classes and the variable classes.
This function is provided so that one can form expressions that link variables and classes, e.g.
# Check that all components are running
vars:
"component" slist => { "cf-monitord", "cf-serverd" };
processes:
"$(component)" restart_class => canonify("start_$(component)");
commands:
"/var/cfengine/bin/$(component)"
ifvarclass => canonify("start_$(component)");
Notice that the function canonify() is provided to convert a
general variable input into a string composed only of legal
characters, using the same algorithm that cfengine uses.
handleType: string
Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A unique id-tag string for referring to this as a promisee elsewhere
Example:
access:
"/source"
handle => "update_rule",
admit => { "127.0.0.1" };
Notes:
A promise handle is like a `goto' label. It allows you to refer to a promise as the promisee
of depends_on client of another promise. Handles are essential for mapping dependencies
and performing impact analyses. In Enterprise versions of CFEngine, promise
handles can also be used in outputs promises, See outputs in agent promises.
depends_onType: slist
Allowed input range: (arbitrary string)
Synopsis: A list of promise handles that this promise builds on or depends on somehow (for knowledge management)
Example:
files:
"/home/mark/tmp/testcopy"
depends_on => { "server_promise_1" },
copy_from => mycopy("/source");
Notes:
This is a list of promise handles for whom this promise is a promisee. In other words, we acknowledge that this promise will be affected by the list of promises whose handles are specified.
This option is only used only for documentation currently. In commercial versions of cfengine, using this attribute leads to automatic documentation about policy relationships for the purpose of Knowledge Management.
commentType: string
Allowed input range: (arbitrary string)
Synopsis: A comment about this promise's real intention that follows through the program
Example:
comment => "This comment follows the data for reference ...",
Notes:
Comments written in code follow the program, they are not merely discarded. They appear in reports and error messages.
agent
bundle agent main(parameter)
{
vars:
"sys_files" slist => {
"/etc/passwd",
"/etc/services"
};
files:
"$(sys_files)" perms => p("root","0644"),
changes => trip_wire;
"/etc/shadow" perms => p("root","0600"),
changes => trip_wire;
"/usr" changes => trip_wire,
depth_search => recurse("inf");
"/tmp" delete => tidy,
file_select => days("2"),
depth_search => recurse("inf");
}
|
Agent bundles contain user-defined promises for cf-agent. The
types of promises and their corresponding bodies are detailed below.
commands promises in ‘agent’
commands:
"/path/to/command args"
args => "more args",
contain => contain_body,
module => true/false;
|
Command containment allows you to make a `sandbox' around a
command, to run it as a non-privileged user inside an isolated
directory tree. CFEngine modules are commands that support a simple
protocol (see below) in order to set additional variables and classes
on execution from user defined code. Modules are intended for use as
system probes rather than additional configuration promises.
In cfengine 3 commands and processes have been separated cleanly. Restarting of processes must be coded as a separate command. This stricter type separation will allow more careful conflict analysis to be carried out.
Output from commands executed here is quoted inline, but prefixed
with the letter ‘Q’ to distinguish it from other output, e.g.
from reports (which is prefixed with the letter ‘R’).
Commands were called shellcommands in cfengine 2.
NOTE: a common mistake in using cfengine is to embed many shell commands instead of using the built-in functionality. Use of cfengine internals is preferred as it assures convergence and proper integrated checking. Extensive use of shell commands will make a cfengine execution very heavy-weight like other management systems. To minimize the system cost of execution, always use cfengine internals.
bundle agent example
{
commands:
"/bin/sleep 10"
action => background;
"/bin/sleep"
args => "20",
action => background;
}
NOTE: when referring to executables whose paths contain spaces, you should quote the entire program string separately so that cfengine knows the name of the executable file. e.g.
commands:
windows::
"\"c:\Program Files\my name with space\" arg1 arg2";
linux::
"\"/usr/bin/funny command name\" -a -b -c";
argsType: string
Allowed input range: (arbitrary string)
Synopsis: Alternative string of arguments for the command (concatenated with promiser string)
Example:
commands: "/bin/echo one" args => "two three";
Notes:
Sometimes it is convenient to separate the arguments to a command from the command itself. The final arguments are the concatenation with one space. So in the example above the command would be
/bin/echo one two three
contain (compound body)Type: (ext body)
useshell’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false embed the command in a shell environment (true)
Default value: false
Example:
body contain example
{
useshell => "true";
}
Notes:
The default is to not use a shell when executing commands. Use of a
shell has both resource and security consequences. A shell consumes an
extra process and inherits environment variables, reads commands from
files and performs other actions beyond the control of cfengine. If
one does not need shell functionality such as piping through multiple
commands then it is best to manage without it. In the windows version
of CFEngine Nova, the command is run in the the “Command Prompt” if
useshell is true.
umask’Allowed input range:
077222772077022027072
Synopsis: The umask value for the child process
Example:
body contain example
{
umask => "077";
}
Notes:
Sets the internal umask for the process. Default value for the mask is
‘077’. On windows, umask is not supported and is thus ignored by
windows versions of CFEngine.
exec_owner’Allowed input range: (arbitrary string)
Synopsis: The user name or id under which to run the process
Example:
body contain example
{
exec_owner => "mysql_user";
}
Notes:
This is part of the restriction of privilege for child processes when
running cf-agent as the root user, or a user with privileges.
Windows requires the clear text password for the user account to run
under. Keeping this in CFEngine policies could be a security
hazard. Therefore, this option is not yet implemented on windows
versions of CFEngine.
exec_group’Allowed input range: (arbitrary string)
Synopsis: The group name or id under which to run the process
Example:
body contain example
{
exec_group => "nogroup";
}
Notes:
This is part of the restriction of privilege for child processes when
running cf-agent as the root group, or a group with
privileges. It is ignored on windows, as processes do not have any
groups associated with them.
exec_timeout’Allowed input range: 1,3600
Synopsis: Timeout in seconds for command completion
Example:
body contain example
{
exec_timeout => "30";
}
Notes:
Attempt to time-out after this number of seconds. This cannot be guaranteed as not all
commands are willing to be interrupted in case of failure.
chdir’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Directory for setting current/base directory for the process
Example:
body contain example
{
chdir => "/containment/directory";
}
Notes:
This command has the effect of placing the running command into a current working
directory equal to the parameter given, i.e. it works like the ‘cd’ shell command.
chroot’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Directory of root sandbox for process
Example:
body contain example
{
chroot => "/private/path";
}
Notes:
Sets the path of the directory that will be experienced as the top-most
root directory for the process. In security parlance, this creates
a `sandbox' for the process. Windows does not support this feature.
preview’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false preview command when running in dry-run mode (with -n)
Default value: false
Example:
body contain example
{
preview => "true";
}
Notes:
Previewing shell scripts during a dry-run is a potentially misleading
activity. It should only be used on scripts that make no changes to
the system. It is cfengine best practice to never write
change-functionality into user-written scripts except as a last
resort: cfengine can apply its safety checks to user defined scripts.
no_output’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false discard all output from the command
Default value: false
Example:
body contain example
{
no_output => "true";
}
Notes:
This is equivalent to piping standard output and error to /dev/null.
moduleType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false whether to expect the cfengine module protocol
Example:
commands:
"/masterfiles/user_script"
module => "true";
Notes:
If true, the module protocol is supported for this script, i.e. it is treated as a user
module. A plug-in module may
be written in any language, it can return any output you like, but lines
which begin with a ‘+’ sign are treated as classes to be defined
(like -D), while lines which begin with a ‘-’ sign are
treated as classes to be undefined (like -N). Lines starting
with ‘=’ are variables/macros to be defined. Any other lines of
output are cited by cf-agent as being erroneous, so you should
normally make your module
completely silent. Here is an example module written in perl.
#!/usr/bin/perl
#
# module:myplugin
#
# lots of computation....
if (special-condition)
{
print "+specialclass";
}
If your module is “simple” and is best expressed as a shell command, then
we suggest that you expose the class being defined in the command being
executed (making it easier to see what classes are used when reading the
promises file). For example, the promises could read as follows (the two
echo commands are to ensure that the shell always exits with a
successful execution of a command):
bundle agent sendmail
{
commands:
# This next module checks a specific failure mode of dcc, namely
# more than 3 error states since the last time we ran cf-agent
is_mailhost::
"/bin/test `/usr/bin/tail -100 /var/log/maillog | /usr/bin/grep 'Milter (dcc): to error state' | /usr/bin/wc -l` -gt 3 && echo '+start_dccm' || echo
''"
contain => shell_command,
module => true;
start_dccm::
"/var/dcc/libexec/start-dccm"
contain => not_paranoid;
}
body contain shell_command
{
useshell => "yes";
}
body contain not_paranoid
{
useshell => "no";
exec_owner => "root";
umask => "22";
}
Modules inherit the environment variables from cfagent and accept arguments, just as a regular command does.
#!/bin/sh
#
# module:myplugin
#
/bin/echo $*
cf-agent defines the classes as an environment variable so that programs
have access to these. E.g. try the following module:
#!/usr/bin/perl
print "Decoding $ENV{CFALLCLASSES}\n";
@allclasses = split (":","$ENV{CFALLCLASSES}");
while ($c=shift(@allclasses))
{
$classes{$c} = 1;
print "$c is set\n";
}
Modules define variables in cf-agent by outputting strings of the form
=variablename=value
These variables end up in a context which has the same name as the module.
When the $(allclasses) variable becomes too large to manipulate conveniently,
you can access the complete list of currently defined classes in the file
/var/cfengine/state/allclasses.
databases promises in ‘agent’
These features apply to Enterprise versions of cfengine only.
CFEngine Nova can interact with commonly used database servers to keep promises about the structure and content of data within them.
There are two main cases of database management to address: small embedded databases and large centralized databases.
CFEngine is a tool whose strength lies distributed management of computers. Databases are often centralized entities that have single point of management, so a large monolithic database is more easily managed with other tools. However, cfengine can still monitor changes and discrepancies, and it can manage smaller embedded databases that are distributed in nature, whether they are SQL, registry or future types.
So creating 100 new databases for test purposes is a task for cfengine, but adding a new item to an important production database is not a task that we recommend using cfengine for.
There are three kinds of database supported by Nova:
Cfengine's ability to make promises about databases depends on the good grace of the database server. Embedded databases are directly part of the system and promises can be made directly. However, databases running through a server process (either on the same host or on a different host) are independent agents and cfengine cannot make promises on their behalf, unless they promise (grant) permission for cfengine to make the changes. Thus the pre-requisite for making SQL database promises is to grant a point of access on the server.
databases:
"database/subkey or table"
database_operation => "create/delete/drop",
database_type => "sql/ms_registry",
database_columns => {
"name,type,size",
"name,type",
},
database_server => body;
body database_server name
{
db_server_owner => "account name";
db_server_password => "password";
db_server_host => "hostname or omit for localhost";
db_server_type => "mysql/posgres";
db_server_connection_db => "database we can connect to";
}
|
body common control
{
bundlesequence => { "databases" };
}
bundle agent databases
{
#commands:
# "/usr/bin/createdb cf_topic_maps",
# contain => as_user("mysql");
databases:
"cf_topic_maps/topics"
database_operation => "create",
database_type => "sql",
database_columns => {
"topic_name,varchar,256",
"topic_comment,varchar,1024",
"topic_id,varchar,256",
"topic_type,varchar,256",
"topic_extra,varchar,26"
},
database_server => myserver;
}
################################################
body database_server myserver
{
any::
db_server_owner => "postgres";
db_server_password => "";
db_server_host => "localhost";
db_server_type => "postgres";
db_server_connection_db => "postgres";
none::
db_server_owner => "root";
db_server_password => "";
db_server_host => "localhost";
db_server_type => "mysql";
db_server_connection_db => "mysql";
}
body contain as_user(x)
{
exec_owner => "$(x)";
}
The promiser in database promises is a concatenation of the database name and underlying tables. This presents a simple hierarchical model that looks like a file-system. This is the normal structure within the Windows registry for instance. Entity-Relation databases do not normally present tables in this way, but no harm is done in representing them as a hierarchy of depth 1.
database_server (compound body)Type: (ext body)
db_server_owner’Allowed input range: (arbitrary string)
Synopsis: User name for database connection
Example:
db_server_owner => "mark";
Notes:
db_server_password’Allowed input range: (arbitrary string)
Synopsis: Clear text password for database connection
Example:
db_server_password => "xyz.1234";
Notes:
db_server_host’Allowed input range: (arbitrary string)
Synopsis: Hostname or address for connection to database, blank means localhost
Example:
db_server_host => "sqlserv.example.org";
Notes:
Hostname or IP address of the server.
db_server_type’Allowed input range:
postgresmysql
Synopsis: The dialect of the database server
Default value: none
Example:
db_server_type => "postgres";
Notes:
db_server_connection_db’Allowed input range: (arbitrary string)
Synopsis: The name of an existing database to connect to in order to create/manage other databases
Example:
body database_server myserver(x)
{
db_server_owner => "$(x)";
db_server_password => "";
db_server_host => "localhost";
db_server_type => "$(mysql)";
db_server_connection_db => "$(x)";
}
where ‘x’ is currently mysql or postgres.
Notes:
In order to create a database on a database server (all of which
practice voluntary cooperation), one has to be able to connect
to the server, however, without an existing database this is not allowed.
Thus, database servers provide a default database that can be connected
to in order to thereafter create new databases. These are called
postgres and mysql for their respective database servers.
For the knowledge agent, this setting is made in the control body,
for database verification promises, it is made in the
database_server body.
database_typeType: (menu option)
Allowed input range:
sqlms_registry
Default value: none
Synopsis: The type of database that is to be manipulated
Example:
database_type => "@var{ms_registry}";
Notes:
database_operationType: (menu option)
Allowed input range:
createdeletedropcacheverifyrestore
Synopsis: The nature of the promise - to be or not to be
Example:
database_operation => "create";
Notes:
database_columnsType: slist
Allowed input range: .*
Synopsis: A list of column definitions to be promised by SQL databases
Example:
"cf_topic_maps/topics"
database_operation => "create",
database_type => "sql",
database_columns => {
"topic_name,varchar,256",
"topic_comment,varchar,1024",
"topic_id,varchar,256",
"topic_type,varchar,256",
"topic_extra,varchar,26"
},
database_server => myserver;
Notes:
Columns are a list of tuplets (Name,type,size). Array items are triplets, and fixed size data elements are doublets.
database_rowsType: slist
Allowed input range: .*,.*
Synopsis: An ordered list of row values to be promised by SQL databases
Example:
bundle agent databases
{
databases:
windows::
# Regsitry has (value,data) pairs in "keys" which are directories
"HKEY_LOCAL_MACHINE\SOFTWARE\CFEngine AS\Cfengine"
database_operation => "create",
database_rows => { "value1,REG_SZ,new value 1", "value2,REG_SZ,new val 2"} ,
database_type => "ms_registry";
}
Notes:
This constraint is used only in adding data to database columns. Rows are considered to be instances of individual columns. In the case of the system registry on Windows, the rows represent data on data-value pairs.
registry_excludeType: slist
Allowed input range: (arbitrary string)
Synopsis: A list of regular expressions to ignore in key/value verification
Example:
databases:
"HKEY_LOCAL_MACHINE\SOFTWARE"
database_operation => "cache",
registry_exclude => { ".*Windows.*CurrentVersion.*",
".*Touchpad.*",
".*Capabilities.FileAssociations.*",
".*Rfc1766.*" ,
".*Synaptics.SynTP.*",
".*SupportedDevices.*8086",
".*Microsoft.*ErrorThresholds"
},
database_type => "ms_registry";
Notes:
During recursive Windows registry scanning, this option allows us to ignore keys of values matching a
list of regular expressions. Some values in the registry are ephemeral and some should not be considered.
This provdes a convenient way of avoiding names. It is analogous to exclude_dirs for files.
environments promises in ‘agent’
Environment promises are available in the CFEngine Nova Edition and above. Environment promises describe enclosed computing environments that can host physical and virtual machines, solaris zones, grids, clouds or other enclosures, including embedded systems. CFEngine will support the convergent maintenance of such inner environments in a fixed location, with interfaces to an external environment.
CFEngine currently seeks to add convergence properties to existing interfaces for automatic self-healing of virtualized environments. The current implementation integrates with libvirt, supporting host virtualization for Xen, KVM, VMWare, etc. Thus CFEngine, running on a virtual host, can maintain the state and deployment of virtual guest machines defined within the libvirt framework. Environment promises are not meant to manage what goes on within the virtual guests: for that purpose, you should run CFEngine directly on the virtual machine, as if it were any other machine.
site1::
"unique_name1"
environment_resources => myresources("2GB","512MB"),
environment_interface => mymachine("hostname"),
environment_type => "xen",
environment_state => "running",
environment_host => "atlas";
"unique_name2"
environment_type => "xen_network",
environment_state => "create",
environment_host => "atlas";
CFEngine currently provides a convergent interface to libvirt.
environment_hostType: string
Allowed input range: [a-zA-Z0-9_!&@$|.()]+
Synopsis: A host-class for the virtual environment host uniquely indicating which physical node will execute this machine
Example:
environments:
linux::
"host1"
comment => "Keep this vm suspended",
environment_resources => myresources,
environment_type => "kvm",
environment_state => "suspended",
environment_host => "ubuntu";
Notes:
History: this feature was introduced in Nova 2.0.0 (2010)
environment_interface (compound body)Type: (ext body)
env_addresses’Allowed input range: (arbitrary string)
Synopsis: The IP addresses of the environment's network interfaces
Example:
body environment_interface vnet(primary)
{
env_name => "$(this.promiser)";
env_addresses => { "$(primary)" };
host1::
env_network => "default_vnet1";
host2::
env_network => "default_vnet2";
}
Notes:
The IP addresses of the virtual machine can be overridden here at run time.
env_name’Allowed input range: (arbitrary string)
Synopsis: The hostname of the virtual environment
Example:
body environment_interface vnet(primary)
{
env_name => "$(this.promiser)";
env_addresses => { "$(primary)" };
host1::
env_network => "default_vnet1";
host2::
env_network => "default_vnet2";
}
Notes:
The `hostname' of a virtual guest may or may not be the same as the identifier used
as `promiser' by the virtualization manager.
env_network’Allowed input range: (arbitrary string)
Synopsis: The hostname of the virtual network
Example:
body environment_interface vnet(primary)
{
env_name => "$(this.promiser)";
env_addresses => { "$(primary)" };
host1::
env_network => "default_vnet1";
host2::
env_network => "default_vnet2";
}
Notes:
environment_resources (compound body)Type: (ext body)
env_cpus’Allowed input range: 0,99999999999
Synopsis: Number of virtual CPUs in the environment
Example:
body environment_resources my_environment
{
env_cpus => "2";
env_memory => "512"; # in KB
env_disk => "1024"; # in MB
}
Notes:
The maximum number of cores or processors in the physical environment will
set a natural limit on this value. If the number is
already set in a specification file, this value will attempt to override it
at run time.
env_memory’Allowed input range: 0,99999999999
Synopsis: Amount of primary storage (RAM) in the virtual environment (KB)
Example:
body environment_resources my_environment
{
env_cpus => "2";
env_memory => "512"; # in KB
env_disk => "1024"; # in MB
}
Notes:
The maximum amount of memory in the physical environment will set a
natural limit on this value. If the number is already set in a
specification file, this value will attempt to override it at run
time.
env_disk’Allowed input range: 0,99999999999
Synopsis: Amount of secondary storage (DISK) in the virtual environment (MB)
Example:
body environment_resources my_environment
{
env_cpus => "2";
env_memory => "512"; # in KB
env_disk => "1024"; # in MB
}
Notes:
This parameter is currently unsupported, for future extension.
env_baseline’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: The path to an image with which to baseline the virtual environment
Example:
env_baseline => "/path/to/image";
Notes:
This function is for future development.
env_spec_file’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: The path to a file containing a technology specific set of promises for the virtual instance
Example:
body environment_resources virt_xml
{
env_spec_file => "/srv/xen/centos5-libvirt-create.xml";
}
You may also quote the file as XML:
body environment_resources virt_xml(host)
{
env_spec_file =>
"<domain type='xen'>
<name>$(host)</name>
<os>
<type>linux</type>
<kernel>/var/lib/xen/install/vmlinuz-ubuntu10.4-x86_64</kernel>
<initrd>/var/lib/xen/install/initrd-vmlinuz-ubuntu10.4-x86_64</initrd>
<cmdline> kickstart=http://example.com/myguest.ks </cmdline>
</os>
<memory>131072</memory>
<vcpu>1</vcpu>
<devices>
<disk type='file'>
<source file='/var/lib/xen/images/$(host).img'/>
<target dev='sda1'/>
</disk>
<interface type='bridge'>
<source bridge='xenbr0'/>
<mac address='aa:00:00:00:00:11'/>
<script path='/etc/xen/scripts/vif-bridge'/>
</interface>
<graphics type='vnc' port='-1'/>
<console tty='/dev/pts/5'/>
</devices>
</domain>
";
}
Notes:
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
environment_stateType: (menu option)
Allowed input range:
createdeleterunningsuspendeddown
Synopsis: The desired dynamical state of the specified environment
Example:
environments:
linux::
"bishwa-kvm1"
comment => "Keep this vm suspended",
environment_resources => myresources,
environment_type => "kvm",
environment_state => "suspended",
environment_host => "ubuntu";
Notes:
The allowed states have the following convergent semantics.
environment_typeType: (menu option)
Allowed input range:
xenkvmesxtestxen_netkvm_netesx_nettest_netzoneec2eucalyptus
Synopsis: Virtual environment type
Example:
bundle agent my_vm_cloud
{
environments:
scope::
"vguest1"
environment_resources => my_environment_template,
environment_interface => vnet("eth0,192.168.1.100/24"),
environment_type => "test",
environment_state => "create",
environment_host => "atlas";
"vguest2"
environment_resources => my_environment_template,
environment_interface => vnet("eth0,192.168.1.101/24"),
environment_type => "test",
environment_state => "delete",
environment_host => "atlas";
}
Notes:
The currently supported types are those supported by libvirt. More will be added as time goes on.
files promises in ‘agent’
Files promises are an umbrella concept for all attributes of files. Operations fall basically into three categories: create, delete and edit.
files:
"/path/file_object"
perms => perms_body,
... ;
|
Prior to version 3, file promises were scattered into many different
types such as files, tidy, copy, links,
etc. File handling in cfengine 3 uses regular expressions everywhere for pattern
matching. The old `wildcard/globbing' expressions ‘*’ and
‘?’ are deprecated, and everything is based consistently on Perl
Compatible Regular Expressions where these are available. If PCRE is
not available on the local system, POSIX extended regular expressions
are used.
There is a natural ordering in file processing that obviates the need for the actionsequence. The trick of using multiple actionsequence items with different classes, e.g.
actionsequence = ( ... files.one .. files.two )
can now be handled more elegantly using bundles. The natural ordering uses that fact that some operations are mutually exclusive and that some operations do not make sense in reverse order. For example, editing a file and then copying onto it would be nonsense. Similarly, you cannot both remove a file and rename it.
File copying
One of the first things users of cfengine 2 will notice is that copying is now `backwards'. Instead of the default object being source and the option being the destination, in cfengine 3 the destination is paramount and the source is an option. This is because the model of voluntary cooperation tells us that it is the object that is changed which is the agent making the promise. One cannot force change onto a destination with cfengine, one can only invite change from a source.
Normal ordering of promise attributes
CFEngine 3 no longer has an `action sequence'. Ordering of operations has, in most cases, a natural ordering which is assumed by the agent. For instance: `delete then create' (normal ordering) makes sense, but `create then delete' does not. This sort of principle can be extended to deal with all aspects of file promises.
The diagram below shows the ordering. Notice that the same ordering applies regardless of file type (plain-file or directory). Note also that file editing is done "atomically" (see `File editing in cfengine 3' for important details).
The pseudo-code for this logic is shown in the diagram and below:
for each file promise-object
{
if (depth_search)
do
DepthSearch (HandleLeaf)
else
(HandleLeaf)
done
}
HandleLeaf()
{
Does leaf-file exist?
NO: create
YES: rename,delete,touch,
do
for all servers in {localhost, @(servers)}
{
if (server-will-provide)
do
if (depth_search)
embedded source-depth-search (use file source)
break
else
(use file source)
break
done
done
}
done
Do all links (always local)
Check Permissions
Do edits
}
Depth searches (recursion) during searches
In cfengine 2 there was the concept of recursion during file searches. Recursion is now called "depth-search". In addition, it was possible to specify wildcards in the base-path for this search. CFEngine 3 replaces the `globbing' symbols with standard regular expressions:
CFEngine 2 CFEngine 3
/one/*/two/thr*/four /one/.*/two/thr.*/four
Note that this now means when searching for “hidden” files (files with names
starting with a `.') or files with specific extensions, you should take care to
escape the dot (e.g., \.cshrc or .*\.txt when you wish it to
mean a literal character and not the “any character” interpretation provided
by regular expression interpretation.
Note that when you do a recursive search, the files '.' and
'..' are never included in the matched files, even if the regular
expresion in the ‘leaf_name’ specifically allows them.
Note also the the filename ‘/dir/ect/ory/.’ is a special case used with the ‘create’ attribute to indicate the directory named ‘/dir/ect/ory’ and not any of the files under it. If you really want to specify a regular expression that matches any single-character filename, use ‘/dir/ect/ory/[\w\W]’ as your promise regular expression (you can't use ‘/dir/ect/ory[^/]’, see below for an explanation.
When we talk about a depth search, it refers to a search for file objects which starts from the one or more matched base-paths as shown in the example above.
Filenames and regular expressions
CFEngine allows regular expressions within filenames, but only after first doing some sanity checking to prevent some readily avoidable problems. The biggest rule you need to know about filenames and regular expressions is that all regular expressions in filenames are bounded by directory separators, and that each component expression is anchored between the directory separators See Anchored vs. unanchored regular expressions. In other words, CFEngine splits up any file paths into its component parts, and then it evaluates any regular expressions at a component-level.
What this means is that the path ‘/tmp/gar.*’ will only match filenames like /tmp/gar, /tmp/garbage and /tmp/garden. It will not match filename like /tmp/gar/baz (because even though the ‘.*’ in a regular expression means "zero or more of any character", CFEngine restricts that to mean "zero or more of any character in a path component"). Correspondingly, CFEngine also restricts where you can use the ‘/’ character (you can't use it in a character class like ‘[^/]’ or in a parenthesized or repeated regular expression component.
This means that regular expressions which include "optional directory components" won't work. You can't have a files promise to tidy the directory ‘(/usr)?/tmp’. Instead, you need to be more verbose and specify ‘/usr/tmp|/tmp’, or even better, think declaratively and create an slist that contains both the strings ‘/tmp’ and ‘/usr/tmp’, and then allow CFEngine to iterate over the list!
This also means that the path ‘/tmp/.*/something’ will match files like /tmp/abc/something or /tmp/xyzzy/something. However, even though the pattern ‘.*’ means "zero or more of any character (except ‘/’)", CFEngine matches files bounded by directory separators. So even though the pathname /tmp//something is technically the same as the pathname /tmp/something, the regular expression ‘/tmp/.*/something’ will not match on the degenerate case of /tmp//something (or /tmp/something).
Promises involving regular expressions
CFEngine can only keep (or repair, or fail to keep) a promise on files which actually exist. If you make a promise based on a wildcard match, then the promise is only ever attempted if the match succeeds. However, if you make a promise which includes a recursive search which includes a wildcard match, then the promise can be kept or repaired (provided that the directory specified in the promise exists). Consider the following two examples, (assuming that there first exist files named /tmp/gar, /tmp/garbage and /tmp/garden). At first blush, the two promises look like they should do the same thing, but there is a subtle difference:
bundle agent foobaz bundle agent foobaz
{ {
files: files:
"/tmp/gar.*" "/tmp"
delete => tidy, delete => tidy,
classes => if_ok("done"); depth_search => recurse("0"),
file_select => gars,
classes => if_ok("done");
}
body file_select gars
{
leaf_name => { "gar.*" };
file_result => "leaf_name";
}
body classes if_ok(x) body classes if_ok(x)
{ {
promise_repaired => { "$(x)" }; promise_repaired => { "$(x)" };
promise_kept => { "$(x)" }; promise_kept => { "$(x)" };
} }
In the first example, when the configuration containing this promise is first executed, any file starting with "gar" that exists in the ‘/tmp’ directory will be removed, and the ‘done’ class will be set. However, when the configuration is executed a second time, the pattern ‘/tmp/gar.*’ will not match any files, and that promise will not even be attempted (and, consequently the ‘done’ class will not be set).
In the second example, when the configuration containing this promise is first executed, any file starting with "gar" that exists in the ‘/tmp’ directory will also be removed, and the ‘done’ class will also be set. The second time the configuration is executed, however, the promise on the ‘/tmp’ directory will still be executed (because ‘/tmp’ of course still exists), and the ‘done’ class will be set, because all files matching the ‘file_select’ attribute have been deleted from that directory.
Local and remote searches
There are two distinct kinds of depth search:
When we are copying or linking to a file source, it is the search over the remote source that drives the content of a promise (the promise is a promise to use what the remote source provides). In general, the sources are on a different device to the images that make the promises. For all other promises, we search over existing local objects.
If we specify depth search together with copy of a directory, then the implied remote source search is assumed, and it is made after the search over local base-path objects has been made. If you mix complex promise body operations in a single prmose, this could lead to confusion about the resulting behaviour, and a warning is issued. In general it is not recommended to mix searches without a full understanding of the consequences, but this might occasionally be useful.
Depth search is not allowed with edit_line promises.
File editing in cfengine 3
CFEngine 2 assumed that all files were line-edited, because it was based on Unix traditions. Since then many new file formats have emerged, including XML. CFEngine 3 opens up the possibiltiy for multiple models of file editing. Line based editing is still present and is both much simplified and much more powerful than previously.
File editing is not just a single kind of promise but a whole range of `promises within files'. It is therefore not merely a body to a single kind of promise, but a bundle of sub-promises. After all, inside each file is a new world of objects that can make promises, quite separate from files' external attributes.
A typical file editing stanza has the elements in the following example.
######################################################################
#
# File editing
#
######################################################################
body common control
{
version => "1.2.3";
bundlesequence => { "outerbundle" };
}
########################################################
bundle agent outerbundle
{
files:
"/home/mark/tmp/cf3_test"
create => "true", # Like autocreate in cf2
edit_line => inner_bundle;
}
########################################################
bundle edit_line inner_bundle
{
vars:
"who" string => "SysAdmin John"; # private variable in bundle
insert_lines:
"/* This file is maintained by CFEngine (see $(who) for details) */",
location => first_line;
replace_patterns:
# replace shell comments with C comments
"#(.*)"
replace_with => C_comment,
select_region => MySection("New section");
reports:
someclass::
"This is file $(edit.filename)";
}
########################################
# Bodies for the library ...
########################################
body replace_with C_comment
{
replace_value => "/* $(match.1) */"; # backreference
occurrences => "all"; # first, last all
}
########################################################
body select_region MySection(x)
{
select_start => "\[$(x)\]";
select_end => "\[.*\]";
}
########################################################
body location first_line
{
before_after => "before";
first_last => "first";
select_line_matching => ".*";
}
There are several things to notice:
edit_line bundle are handled
"atomically". CFEngine edits files like this:
delete_lines, field_edits,
insert_lines, and finally replace_patterns promises), CFEngine
checks to see if the new file is the same as the original one. If there are
no differences, the promises have converged, so it deletes the copy, and the
original is left completely unmodified.
$(edit.filename) contains the name of the file being edited within
an edit bundle.
In the example above, back references are used to allow conversion of comments from shell-style to C-style.
Another example of files promises is to look for changes in files. The
following example reports on all recent changes to files in a directory by
maintaining the most recent version of the md5 hash of the file
contents. Similar checks can be used to examine metadata or both the contents
and metadata, as well as using different difference checks. The Community
Edition only reports that changes were found, but Enterprise versions of
CFEngine can also report on what exactly the significant changes were.
bundle agent example
{
files:
"/home/mark/tmp" -> "Security team"
changes => lay_a_tripwire,
depth_search => recurse("inf"),
action => background;
}
#########################################################
body changes lay_a_tripwire
{
hash => "md5";
report_changes => "content";
update => "yes";
}
acl (compound body)Type: (ext body)
aces’Allowed input range: ((user|group):[^:]+:[-=+,rwx()dtTabBpcoD]*(:(allow|deny))?)|((all|mask):[-=+,rwx()]*(:(allow|deny))?)
Synopsis: Native settings for access control entry
Example:
body acl template
{
acl_method => "overwrite";
acl_type => "posix";
acl_directory_inherit => "parent";
aces => {
"user:*:r(wwx),-r:allow",
"group:*:+rw:allow",
"mask:x:allow",
"all:r"
};
}
Notes:
Access Control Lists are only available with CFEngine Nova or above. Form of the permissions is:
aces => {
"user:uid:mode[:perm_type]", ...,
"group:gid:mode[:perm_type]", ...,
"all:mode[:perm_type]"
};
|
user indicates that the line applies to a user specified
by the user identitfier uid. mode is the permission
mode string.
group indicates that the line applies to a group specified
by the group identitfier gid. mode is the permission
mode string.
all indicates that the line applies to every
user. mode is the permission mode string.
uid is a valid user identifier for the system and
cannot be empty. However, uid can be set to * as a synonym
for the entity that owns the file system object (e.g. user:*:r).
gid is a valid group identifier for the system and
cannot be empty. However, in some acl types, gid can be set
to * to indicate a special group (e.g. in POSIX this refers to the
file group).
mode is one or more strings
op|perms|(nperms); a concatenation of op,
perms and optionally (nperms), see below, separated
with commas (e.g. +rx,-w(s)). mode is parsed from left to
right.
op specifies the operation on any existing permissions,
if the defined ACE already exists. op can be =, empty, + or
-. = or empty sets the permissions to the ACE as stated, + adds and
- removes the permissions from any existing ACE.
nperms (optional) specifies file system specific
(native) permissions. Only valid if acl_type is
defined. nperms will only be enforced if the file object is
stored on a file system supporting the acl type set in
acl_type (e.g. nperms will be ignored if
acl_type:ntfs and the object is stored on a file system
not supporting ntfs ACLs). Valid values for nperms varies with
different ACL types, and is defined in subsequent sections.
perm_type (optional) can be set to either allow or
deny, and defaults to allow. deny is only valid
if acl_type is set to an ACL type that support deny
permissions. A deny ACE will only be enforced if the file
object is stored on a file system supporting the acl type set in
acl_type.
gperms (generic permissions) is a concatenation of zero or more
of the characters shown in the table below. If left empty,
none of the permissions are set.
| Flag | Description | Semantics on file | Semantics on directory
|
|---|---|---|---|
r | Read | Read data, permissions, attributes | Read
directory contents, permissions, attributes
|
w | Write | Write data | Create, delete, rename subobjects
|
x | Execute | Execute file | Access subobjects
|
Note that the r permission is not neccessary to read an object's
permissions and attributes in all file systems (e.g. in POSIX, having
x on its containing directory is sufficient).
acl_directory_inherit’Allowed input range:
nochangeparentspecifyclear
Synopsis: Access control list type for the affected file system
Example:
body acl template
{
acl_method => "overwrite";
acl_type => "posix";
acl_directory_inherit => "parent";
aces => {
"user:*:rwx:allow",
"group:*:+rw:allow",
"mask:rx:allow",
"all:r"
};
}
Notes:
Directories have ACLs associated with them, but they also have the ability to inherit an ACL to sub-objects created within them. POSIX calls the former ACL type "access ACL" and the latter "default ACL", and we will use the same terminology.
The constraint acl_directory_inherit gives control over the
default ACL of directories. The default ACL can be left unchanged
(nochange), empty (clear), or be explicitly specified
(specify). In addition, the default ACL can be set equal to the
directory's access ACL (parent). This has the effect that child
objects of the directory gets the same access ACL as the directory.
acl_method’Allowed input range:
appendoverwrite
Synopsis: Editing method for access control list
Example:
body acl template
{
acl_method => "overwrite";
acl_type => "posix";
aces => { "user:*:rw:allow", "group:*:+r:allow", "all:"};
}
Notes:
When defining an ACL, we can either use an existing ACL as the
starting point, or state all entries of the ACL. If we just care about
one entry, say that the superuser has full access, the method
constraint can be set to append, which is the default. This has
the effect that all the existing ACL entries that are not mentioned
will be left unchanged. On the other hand, if method is set to
overwrite, the resulting ACL will only contain the mentioned
entries. When doing this, it is important to check that all the
required ACL entries are set, e.g. owning user, group and all in Posix
ACLs.
acl_type’Allowed input range:
genericposixntfs
Synopsis: Access control list type for the affected file system
Example:
body acl template
{
acl_type => "ntfs";
aces => { "user:Administrator:rwx(po)", "user:Auditor:r(o)"};
}
Notes:
ACLs are supported on multiple platforms, which may have different
sets of available permission flags. By using the constraint
acl_type, we can specify which platform, or ACL API, we are
targeting with the ACL. The default, generic, is designed to
work on all supported platforms. However, if very specific permission
flags are required, like “Take Ownership” on the NTFS platform, we
must set acl_type to indicate the target platform. Currently,
the supported values are posix and ntfs.
specify_inherit_aces’Allowed input range: ((user|group):[^:]+:[-=+,rwx()dtTabBpcoD]*(:(allow|deny))?)|((all|mask):[-=+,rwx()]*(:(allow|deny))?)
Synopsis: Native settings for access control entry
Example:
body acl template
{
specify_inherit_aces => { "all:r" };
}
Notes:
specify_inherit_aces (optional) is a list of access control
entries that are set on child objects. It is also parsed from left
to right and allows multiple entries with same entity-type and
id. Only valid if acl_directory_inherit is set to
specify.
This is an acl which makes explicit setting for the acl inherited by new objects within a directory. It is included for those implementations that do not have a clear inheritance policy.
changes (compound body)Type: (ext body)
hash’Allowed input range:
md5sha1sha256sha384sha512best
Synopsis: Hash files for change detection
Example:
body changes example
{
hash => "md5";
}
Notes:
The best option cross correlates the best two available
algorithms known in the OpenSSL library.
report_changes’Allowed input range:
allstatscontentnone
Synopsis: Specify criteria for change warnings
Example:
body changes example
{
report_changes => "content";
}
Notes:
Files can change in permissions and contents, i.e. external or internal attributes.
If ‘all’ is chosen all attributes are checked.
update_hashes’Allowed input range:
truefalseyesnoonoff
Synopsis: Update hash values immediately after change warning
Example:
body changes example
{
update_hashes => "true";
}
Notes:
If this is positive, file hashes should be updated as soon as a change
is registered so that multiple warnings are not given about a single
change. This applies to addition and removal too.
report_diffs’Allowed input range:
truefalseyesnoonoff
Synopsis: Generate reports summarizing the major differences between individual text files
Example:
body changes example
{
report_diffs => "true";
}
Notes:
This feature is available only in enterprise levels Nova and above.
If true, CFEngine will log a `diff' summary of major changes to the files. It is not permitted to combine this promise with a depth search, since this would consume a dangerous amount of resources and would lead to unreadable reports.
The feature is intented as a informational summary, not as a version control function suitable for transaction control. If you want to do versioning on system files, you should keep a single repository for them and use cfengine to synchronize changes from the repository source. Repositories should not be used to attempt to capture random changes of the system.
copy_from (compound body)Type: (ext body)
source’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Reference source file from which to copy
Example:
body copy_from example
{
source => "/path/to/source";
}
# or
body link_from example
{
source => "/path/to/source";
}
Notes:
For remote copies this refers to the file name on the remote server.
servers’Allowed input range: [A-Za-z0-9_.:-]+
Synopsis: List of servers in order of preference from which to copy
Example:
body copy_from example
{
servers => { "primary.example.org", "secondary.example.org",
"tertiary.other.domain" };
}
Notes:
The servers are tried in order until one of them succeeds.
collapse_destination_dir’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false Place files in subdirectories into the root destination directory during copy
Example:
body copy_from mycopy(from,server)
{
source => "$(from)";
servers => { "$(server)" };
collapse_destination_dir => "true";
}
Notes:
Under normal operations, recursive copies cause cfengine to track subdirectories of files. So, for instance, if we copy recurively from src to dest, then src/subdir/file will map to dest/subdir/file.
By setting this option to ‘true’, the promiser destination
directory promises to aggregate files searched from all subdirectories
into itself, i.e. a single destination directory.
compare’Allowed input range:
atimemtimectimedigesthashexistsbinary
Synopsis: Menu option policy for comparing source and image file attributes
Default value: mtime or ctime differs
Example:
body copy_from example
{
compare => "digest";
}
Notes:
The default copy method is ‘mtime’ (modification time), meaning that the source file is copied to the destination (promiser) file, if the source file has been modified more recently than the destination.
The different options are:
mtime CFEngine copies the file if the modification time of the source
file is more recent than that of the promised file
ctime CFEngine copies the file if the creation time of the source file
is more recent than that of the promised file
atime CFEngine copies the file if the modification time or creation
time of the source file is more recent than that of the promised file. If the
times are equal, a byte-for-bye comparison is done on the files to determine
if it needs to be copied.
exists CFEngine copies the file if the promised file does not already
exist.
binary CFEngine copies the file if they are both plain files and a
byte-for-byte comparison determines that they are different. If both are not
plain files, CFEngine reverts to comparing the mtime and ctime
of the files. If the source file is on a different machine (i.e., network
copy), then hash is used instead to reduce network bandwidth.
hash CFEngine copies the file if they are both plain files and a
message digest comparison indicates that the files are different. In
Enterprise versions of CFEngine version 3.1.0 and later, SHA256 is used as a
message digest hash to conform with FIPS; in older Enterprise versions of
CFEngine and all Community versions, MD5 is used.
digest a synonym for hash
copy_backup’Allowed input range:
truefalsetimestamp
Synopsis: Menu option policy for file backup/version control
Default value: true
Example:
body copy_from example
{
copy_backup => "timestamp";
}
Notes:
Determines whether a backup of the previous version is kept on the
system. This should be viewed in connection with the system repository,
since a defined repository affects the location at which the backup
is stored.
encrypt’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false use encrypted data stream to connect to remote host
Default value: false
Example:
body copy_from example
{
servers => { "remote-host.example.org" };
encrypt => "true";
}
Notes:
Client connections are encrypted with using a Blowfish randomly
generated session key. The intial connection is encrypted using the
public/private keys for the client and server hosts.
check_root’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false check permissions on the root directory when depth_search
Example:
body copy_from example
{
check_root => "true";
}
Notes:
When copying files recursively (by depth search), this flag determines
whether the permissions of the root directory should be set from the
root of the source. The default is to check only copied file objects
and subdirectories within this root (false).
copylink_patterns’Allowed input range: (arbitrary string)
Synopsis: List of patterns matching files that should be linked instead of copied
Example:
body copy_from example
{
copylink_patterns => { "special_node1", "other_node.*" };
}
Notes:
The matches are performed on the last node of the filename, i.e. the
file without its path. As windows does not support symbolic links,
this feature is not available there.
copy_size’Allowed input range: 0,inf
Synopsis: Integer range of file sizes that may be copied
Default value: any size range
Example:
body copy_from example
{
copy_size => irange("0","50000");
}
Notes:
The use of the irange function is optional. Ranges may also be
specified as a comma separated numbers.
findertype’Allowed input range:
MacOSX
Synopsis: Menu option for default finder type on MacOSX
Example:
body copy_from example
{
findertype => "MacOSX";
}
Notes:
This applies only to the Macintosh OSX variants.
linkcopy_patterns’Allowed input range: (arbitrary string)
Synopsis: List of patterns matching files that should be replaced with symbolic links
Example:
body copy_from mycopy(from)
{
source => "$(from)";
linkcopy_patterns => { ".*" };
}
Notes:
The pattern matches the last node filename (i.e. without the absolute
path). Windows only supports hard links, see link_type.
link_type’Allowed input range:
symlinkhardlinkrelativeabsolutenone
Synopsis: Menu option for type of links to use when copying
Default value: symlink
Example:
body link_from example
{
link_type => "hard";
}
Notes:
What kind of link should be used to link files. Users are advised to be wary of `hard links' (see Unix manual pages for the ‘ln’ command). The behaviour of non-symbolic links is often precarious and unpredictable. However, hard links are the only supported type by windows.
Note that ‘symlink’ is synonymous with ‘absolute’ links, which
are different from ‘relative’ links. Although all of these are symbolic
links, the nomenclature here is defined such that ‘symlink’ and
‘absolute’ are equivalent . When verifying a link, choosing
`relative' means that the link must be relative to the source, so
relative and absolute links are mutually exclusive.
force_update’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false force copy update always
Default value: false
Example:
body copy_from example
{
force_update => "true";
}
Notes:
Warning: this is a non-convergent operation. Although the end point
might stabilize in content, the operation will never quiesce. Use of
this feature is not recommended except in exceptional circumstances
since it creates a busy-dependency. If the copy is a network copy,
the system will be disturbed by network disruptions.
force_ipv4’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false force use of ipv4 on ipv6 enabled network
Default value: false
Example:
body copy_from example
{
force_ipv4 => "true";
}
Notes:
IPv6 should be harmless to most users unless you have a partially
or misconfigured setup.
portnumber’Allowed input range: 1024,99999
Synopsis: Port number to connect to on server host
Example:
body copy_from example
{
portnumber => "5308";
}
Notes:
The standard or registered port number is tcp/5308. CFEngine does not
presently use its registered udp port with the same number, but this
could change in the future.
preserve’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false whether to preserve file permissions on copied file
Default value: false
Example:
History: Was introduced in version 3.1.0b3,Nova 2.0.0b1 (2010)
Fill me in (./bodypart_preserve_example.texinfo)
""
Notes:
History: Was introduced in version 3.1.0b3,Nova 2.0.0b1 (2010)
Fill me in (./bodypart_preserve_notes.texinfo)
""
purge’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false purge files on client that do not match files on server when a depth_search is used
Default value: false
Example:
body copy_from example
{
purge => "true";
}
Notes:
Purging files is a potentially dangerous matter during a file copy it implies that any promiser (destination) file which is not matched by a source will be deleted. Since there is no source, this means the file will be irretrievable. Great care should be exercised when using this feature.
Note that purging will also delete backup files generated during
the file copying if copy_backup is set to true.
stealth’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false whether to preserve time stamps on copied file
Default value: false
Example:
body copy_from example
{
stealth => "true";
}
Notes:
Preserves file access and modification times on the promiser files.
timeout’Allowed input range: 1,3600
Synopsis: Connection timeout, seconds
Example:
body agent control
{
timeout => "10";
}
Notes:
Timeout in seconds.
trustkey’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false trust public keys from remote server if previously unknown
Default value: false
Example:
body copy_from example
{
trustkey => "true";
}
Notes:
If the server's public key has not already been trusted, this allows us to accept the key in automated key-exchange.
Note that, as a simple security precaution, trustkey should normally be set to ‘false’, to avoid key exchange with a server one is not one hundred percent sure about, though the risks for a client are rather low. On the server-side however, trust is often granted to many clients or to a whole network in which possibly unauthorized parties might be able to obtain an IP address, thus the trust issue is most important on the server side.
As soon as a public key has been exchanged, the trust option has no
effect. A machine that has been trusted remains trusted until
its key is manually revoked by a system administrator. Keys are
stored in WORKDIR/ppkeys.
type_check’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false compare file types before copying and require match
Example:
body copy_from example
{
type_check => "false";
}
Notes:
File types at source and destination should normally match in order for
updates to overwrite them. This option allows this checking to be switched off.
verify’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false verify transferred file by hashing after copy (resource penalty)
Default value: false
Example:
body copy_from example
{
verify => "true";
}
Notes:
This is a highly resource intensive option, not recommended for large file transfers.
createType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false whether to create non-existing file
Example:
files:
"/path/plain_file"
create => "true";
"/path/dir/."
create => "true";
Notes:
Directories are created by using the ‘/.’ to signify a directory type. Note that, if no permissions are specified, mode 600 is chosen for a file, and mode 755 is chosen for a directory. If you cannot accept these defaults, you should specify permissions.
Note that technically, ‘/.’ is a regular expression. However, it is used as a special case meaning "directory". See the filenames and regular expressions near the beginning of the section on files promises for a more complete discussion.
Note: In general, you should not use create with
copy_from or link_from
in files promises. These latter attributes automatically
create the promised file, and using create may actually prevent the
copy or link promise from being kept (since create acts first, which
may affect file comparison or linking operations).
delete (compound body)Type: (ext body)
dirlinks’Allowed input range:
deletetidykeep
Synopsis: Menu option policy for dealing with symbolic links to directories during deletion
Example:
body delete example
{
dirlinks => "keep";
}
Notes:
Links to directories are normally removed just like any other link or file objects. By keeping directory links, you preserve the logical directory structure of the file system so that a link to a directory is not removed but is treated as a directory to be descended into.
The value keep instructs cfengine not to remove directory links.
The values delete and tidy are synonymous, and instruct
cfengine to remove directory links.
Default value (only if body is present):
The default value only has significance if there is a delete body
present. If there is no delete body, then files (and directory links)
are not deleted.
dirlinks => delete
rmdirs’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false whether to delete empty directories during recursive deletion
Example:
body delete example
{
rmdirs => "true";
}
Notes:
When deleting files recursively from a base directory, should we delete empty directories also, or keep the directory structure intact?
Note the parent directory of a search is not deleted in recursive deletions. In cfengine 2 there was an option to delete the parent of the search, but now in cfengine 3, you must code a separate promise to delete the single parent object.
bundle agent cleanup
{
files:
# This will not delete the parent
"/home/mark/tmp/testcopy"
delete => tidyfiles,
file_select => changed_within_1_year,
depth_search => recurse("inf");
# Now delete the parent.
"/home/mark/tmp/testcopy"
delete => tidyfiles;
}
body delete tidyfiles
{
dirlinks => "delete";
rmdirs => "true";
}
body file_select changed_within_1_year
{
mtime => irange(ago(1,0,0,0,0,0),now);
file_result => "mtime";
}
Default value (only if body is present):
The default value only has significance if there is a delete body
present. If there is no delete body, then files (and directories)
are not deleted.
rmdirs => true
depth_search (compound body)Type: (ext body)
depth’Allowed input range: 0,99999999999
Synopsis: Maximum depth level for search
Example:
body depth_search example
{
depth => "inf";
}
Notes:
This was previous called `recurse' in earlier versions of cfengine. Note that the value ‘inf’ may be used for an unlimited value.
When searching recursively from a directory, the parent directory is
not part of the search. It is only the anchor point. To alter the parent,
a separate non-recursive promise should be made.
exclude_dirs’Allowed input range: .*
Synopsis: List of regexes of directory names NOT to include in depth search
Example:
body depth_search
{
# no dot directories
exclude_dirs => { "\..*" };
}
Notes:
Directory names are treated specially when searching recursively through a
file system.
include_basedir’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false include the start/root dir of the search results
Example:
body depth_search example
{
include_basedir => "true";
}
Notes:
When checking files recursively (with depth_search) the promiser
is a directory. This parameter determines whether that initial directory
should be considered part of the promise or simply a boundary which marks
the edge of the search. If true, the promiser directory will also promise
the same attributes as the files inside it.
include_dirs’Allowed input range: .*
Synopsis: List of regexes of directory names to include in depth search
Example:
body depth_search example
{
include_dirs => { "subdir1", "subdir2", "pattern.*" };
}
Notes:
This is the complement of exclude_dirs.
rmdeadlinks’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false remove links that point to nowhere
Default value: false
Example:
body depth_search example
{
rmdeadlinks => "true";
}
Notes:
If we find links that point to non-existence files, should we delete them or keep them?
traverse_links’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false traverse symbolic links to directories (false)
Default value: false
Example:
body depth_search example
{
traverse_links => "true";
}
Notes:
If this is true, cf-agent will treat symbolic links to
directories as if they were directories. Normally this is considered a
potentially dangerous assumption and links are not traversed.
xdev’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false exclude directories that are on different devices
Default value: false
Example:
body depth_search example
{
xdev => "true";
}
Notes:
edit_lineType: (ext bundle) (Separate Bundle)
edit_xmlType: (ext bundle) (Separate Bundle)
edit_defaults (compound body)Type: (ext body)
edit_backup’Allowed input range:
truefalsetimestamprotate
Synopsis: Menu option for backup policy on edit changes
Default value: true
Example:
body edit_defaults example
{
edit_backup => "timestamp";
}
Notes:
empty_file_before_editing’Allowed input range:
truefalseyesnoonoff
Synopsis: Baseline memory model of file to zero/empty before commencing promised edits
Default value: false
Example:
body edit_defaults example
{
empty_file_before_editing => "true";
}
Notes:
Emptying a file before reconstructing its contents according to a
fixed recipe allows an ordered procedure to be convergent.
max_file_size’Allowed input range: 0,99999999999
Synopsis: Do not edit files bigger than this number of bytes
Example:
body edit_defaults example
{
max_file_size => "50K";
}
Notes:
A local, per-file sanity check to make sure the file editing is sensible.
If this is set to zero, the check is disabled and any size may be edited.
The default value of max_file_size is determined by the global
control body setting of See editfilesize in agent, whose default value is
100k.
recognize_join’Allowed input range:
truefalseyesnoonoff
Synopsis: Join together lines that end with a backslash, up to 4kB limit
Default value: false
Example:
files:
"/tmp/test_insert"
create => "true",
edit_line => Insert("$(insert.v)"),
edit_defaults => join;
}
#
body edit_defaults join
{
recognize_join => "true";
}
Notes:
If set to true, this option allows CFEngine to process line based files with backslash continuation. The default is to not process continuation backslashes.
Back slash lines will only be concatenated if the file requires editing, and will not be restored. Restoration of the backslashes is not possible in a meaningful and convergent fashion.
file_select (compound body)Type: (ext body)
leaf_name’Allowed input range: (arbitrary string)
Synopsis: List of regexes that match an acceptable name
Example:
body file_select example
{
leaf_name => { "S[0-9]+[a-zA-Z]+", "K[0-9]+[a-zA-Z]+" };
file_result => "leaf_name";
}
Notes:
This pattern matches only the node name of the file, not its path.
path_name’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: List of pathnames to match acceptable target
Example:
body file_select example
{
leaf_name => { "prog.pid", "prog.log" };
path_name => { "/etc/.*", "/var/run/.*" };
file_result => "leaf_name.path_name"
}
Notes:
Path name and leaf name can be conveniently tested for separately by use
of appropriate regular expressions.
search_mode’Allowed input range: [0-7augorwxst,+-]+
Synopsis: A list of mode masks for acceptable file permissions
Example:
#######################################################
#
# Searching for permissions
#
#######################################################
body common control
{
any::
bundlesequence => {
"testbundle"
};
version => "1.2.3";
}
############################################
bundle agent testbundle
{
files:
"/home/mark/tmp/testcopy"
file_select => by_modes,
transformer => "/bin/echo DETECTED $(this.promiser)",
depth_search => recurse("inf");
}
############################################
body file_select by_modes
{
search_mode => { "711" , "666" };
file_result => "mode";
}
############################################
body depth_search recurse(d)
{
depth => "$(d)";
}
Notes:
The mode may be specified in symbolic or numerical form with ‘+’
and ‘-’ constraints.
Note that concatenation ug+s implies u OR g,
and u+g,u+s implies u AND g.
search_size’Allowed input range: 0,inf
Synopsis: Integer range of file sizes
Example:
body file_select example
{
search_size => irange("0","20k");
file_result => "size";
}
Notes:
search_owners’Allowed input range: (arbitrary string)
Synopsis: List of acceptable user names or ids for the file, or regexes to match
Example:
body file_select example
{
search_owners => { "mark", "jeang", "student_.*" };
file_result => "owner";
}
Notes:
A list of regular expressions any of which must match the entire userid,
(that is, it is anchored See Anchored vs. unanchored regular expressions).
Note that windows does not have user ids, only names.
search_groups’Allowed input range: (arbitrary string)
Synopsis: List of acceptable group names or ids for the file, or regexes to match
Example:
body file_select example
{
search_groups => { "users", "special_.*" };
file_result => "group";
}
Notes:
A list of regular expressions, any of which which must match the entire group,
(that is, it is anchored See Anchored vs. unanchored regular expressions).
Note that on windows, files do not have group associations.
search_bsdflags’Allowed input range: [+-]*[(arch|archived|nodump|opaque|sappnd|sappend|schg|schange|simmutable|sunlnk|sunlink|uappnd|uappend|uchg|uchange|uimmutable|uunlnk|uunlink)]+
Synopsis: String of flags for bsd file system flags expected set
Example:
body file_select xyz
{
search_bsdflags => "archived|dump";
file_result => "bsdflags";
}
Notes:
Extra BSD file system flags (these have no effect on non-BSD versions of
cfengine). See the manual page for chflags for more details.
ctime’Allowed input range: 0,2147483647
Synopsis: Range of change times (ctime) for acceptable files
Example:
body files_select example
{
ctime => irange(ago(1,0,0,0,0,0),now);
file_result => "ctime";
}
Notes:
The file's change time refers to both modification of content and attributes
such as permissions. On windows, ctime refers to creation time.
mtime’Allowed input range: 0,2147483647
Synopsis: Range of modification times (mtime) for acceptable files
Example:
body files_select example
{
# Files modified more than one year ago (i.e., not in mtime range)
mtime => irange(ago(1,0,0,0,0,0),now);
file_result => "!mtime";
}
Notes:
The file's modification time refers to both modification of content but not other attributes
such as permissions.
atime’Allowed input range: 0,2147483647
Synopsis: Range of access times (atime) for acceptable files
Example:
body file_select used_recently
{
# files accessed within the last hour
atime => irange(ago(0,0,0,1,0,0),now);
file_result => "atime";
}
body file_select not_used_much
{
# files not accessed since 00:00 1st Jan 2000 (in the local timezime)
atime => irange(on(2000,1,1,0,0,0),now);
file_result => "!atime";
}
Notes:
A range of times during which a file was accessed can be specified in
a file_select body. (Like file filters in cfengine 2.)
exec_regex’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Matches file if this regular expression matches any full line returned by the command
Example:
body file_select example
{
exec_regex => "SPECIAL_LINE: .*";
exec_program => "/path/test_program $(this.promiser)";
file_result => "exec_program.exec_regex";
}
Notes:
The regular expression must be used in conjunction with the exec_program test.
In this way the program must both return exit status 0 and its
output must match the regular expression. The entire output must
be matched (that is, as if the regex is anchored, See Anchored vs. unanchored regular expressions).
exec_program’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Execute this command on each file and match if the exit status is zero
Example:
body file_select example
{
exec_program => "/path/test_program $(this.promiser)";
file_result => "exec_program";
}
Notes:
This is part of the customizable file search criteria.
If the user-defined program returns exit status 0, the file is considered matched.
file_types’Allowed input range:
plainregsymlinkdirsocketfifodoorcharblock
Synopsis: List of acceptable file types from menu choices
Example:
body file_select filter
{
file_types => { "plain","symlink" };
file_result => "file_types";
}
Notes:
File types vary in details between operating systems. The main POSIX
types are provided here as menu options.
issymlinkto’Allowed input range: (arbitrary string)
Synopsis: List of regular expressions to match file objects
Example:
body file_select example
{
issymlinkto => { "/etc/[^/]*", "/etc/init\.d/[a-z0-9]*" };
}
Notes:
A list of regular expressions. If the file is a symbolic link which
points to files matched by one of these expressions, the file will be
selected. As windows does not support symbolic links, this attribute
is not applicable there.
file_result’Allowed input range: [(leaf_name|path_name|file_types|mode|size|owner|group|atime|ctime|mtime|issymlinkto|exec_regex|exec_program|bsdflags)[|&!.]*]*
Synopsis: Logical expression combining classes defined by file search criteria
Example:
body file_select year_or_less
{
mtime => irange(ago(1,0,0,0,0,0),now);
file_result => "mtime";
}
body file_select my_pdf_files_morethan1dayold
{
mtime => irange(ago(0,0,1,0,0,0),now);
leaf_name => { ".*\.pdf" , ".*\.fdf" };
search_owners => { "mark" };
file_result => "owner.leaf_name.!mtime";
}
Notes:
Sets the criteria for file selection outcome during file searches. The syntax is the same as for a class expression, since the file selection is a classification of the file-search in the same way that system classes are a classification of the abstract host-search (that is, you may specify a boolean expression involving any of the file-matching components). In this way, you may specify arbitrarily complex file-matching parameters, such as what is shown above, "is owned by mark, has the extension '.pdf' or '.fdf', and whose modification time is not between 1 day ago and now (that is, it is older than 1 day)".
Items in the boolean expression in file_result must be from the
following list:
link_from (compound body)Type: (ext body)
copy_patterns’Allowed input range: (arbitrary string)
Synopsis: A set of patterns that should be copied ansd synchronized instead of linked
Example:
body link_from example
{
copy_patterns => { "special_node1", "/path/special_node2" };
}
Notes:
During the linking of files, it is sometimes useful to buffer changes
with an actual copy, especially if the link is to an emphemeral file
system. This list of patterns matches files that arise during a
linking policy. A positive match means that the file should be copied
and updated by modification time.
link_children’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false whether to link all directory's children to source originals
Default value: false
Example:
body link_from example
{
link_children => "true";
}
Notes:
If the promiser is a directory, instead of copying the children, link them to the
source.
link_type’Allowed input range:
symlinkhardlinkrelativeabsolutenone
Synopsis: The type of link used to alias the file
Default value: symlink
Example:
body link_from example
{
link_type => "hard";
}
Notes:
What kind of link should be used to link files. Users are advised to be wary of `hard links' (see Unix manual pages for the ‘ln’ command). The behaviour of non-symbolic links is often precarious and unpredictable. However, hard links are the only supported type by windows.
Note that ‘symlink’ is synonymous with ‘absolute’ links, which
are different from ‘relative’ links. Although all of these are symbolic
links, the nomenclature here is defined such that ‘symlink’ and
‘absolute’ are equivalent . When verifying a link, choosing
`relative' means that the link must be relative to the source, so
relative and absolute links are mutually exclusive.
source’Allowed input range: (arbitrary string)
Synopsis: The source file to which the link should point
Example:
body copy_from example
{
source => "/path/to/source";
}
# or
body link_from example
{
source => "/path/to/source";
}
Notes:
For remote copies this refers to the file name on the remote server.
when_linking_children’Allowed input range:
override_fileif_no_such_file
Synopsis: Policy for overriding existing files when linking directories of children
Example:
body link_from example
{
when_linking_children => "if_no_such_file";
}
Notes:
The options refer to what happens if the directory exists already and
is already partially populated with files. If the directory being
copied from contains a file with the same name as that of a link
to be created, we must decide whether to override the existing
destination object with a link or simply omit the automatic
linkage for files that already exist. The latter case can
be used to make a copy of one directory with certain fields
overridden.
when_no_source’Allowed input range:
forcedeletenop
Synopsis: Behaviour when the source file to link to does not exist
Default value: nop
Example:
body link_from example
{
when_no_file => "force";
}
Notes:
If we try to create a link to a file that does not exist a link, how should cfengine respond? The options are to force the creation to a file that does not (yet) exist, delete any existing link, or do nothing.
move_obstructionsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false whether to move obstructions to file-object creation
Example:
files:
"/tmp/testcopy"
copy_from => mycopy("/tmp/source"),
move_obstructions => "true",
depth_search => recurse("inf");
Notes:
If we have promised to make file X a link, but it already exists as a file, or vice-versa, or if a file is blocking the creation of a directory etc, then normally cfengine will report an error. If this is set, existing objects will be moved aside to allow the system to heal without intervention. Files and directories are saved/renamed, but symbolic links are deleted.
Note that symbolic links for directories are treated as directories, not links. This behaviour can be discussed, but the aim is to err on the side of caution. Some operating systems (Solaris) use symbolic links in path names. Copying to a directory could then result in renaming of the important link, if the behaviour were different.
pathtypeType: (menu option)
Allowed input range:
literalregexguess
Synopsis: Menu option for interpreting promiser file object
Example:
files:
"/var/lib\d"
pathtype => "guess", # best guess (default)
perms => system;
"/var/lib\d"
pathtype => "regex", # force regex interpretation
perms => system;
"/var/.*/lib"
pathtype => "literal", # force literal interpretation
perms => system;
Notes:
By default, CFEngine makes an educated guess as to whether the promise
pathname involves a regular expression or not. This guesswork is needed due
to cross-platform differences in filename interpretation.
If CFEngine guesses (or is told) that the pathname uses a regular expression pattern, it will undertake a file search to find possible matches. This can consume significant resources, and so the ‘guess’ option will always try to optimize this. Guesswork is, however, imperfect, so you have the option to declare your intention.
If the keyword literal is invoked, a path will be treated as a
literal string regardless of what characters is contains. If it is
declared ‘regex’, it will be treated as a pattern to match.
Note that CFEngine splits the promiser up into path links before matching, so that each link in the path chain is matched separately. Thus it it meaningless to have a ‘/’ in a regular expression, as the comparison will never see this character.
In the examples above, at least one case implies an iteration over all files/directories matching the regular expression, while the last case means a single literal object with a name composed of dots and stars.
Furthermore, on Windows paths using regex must use the forward slash
(/) as path separator, since the backward slash has a special meaning
in a regular expression. Literal paths may also use backslash (\) as a
path separator; See Regular expressions in paths, for more information.
perms (compound body)Type: (ext body)
bsdflags’Allowed input range: [+-]*[(arch|archived|nodump|opaque|sappnd|sappend|schg|schange|simmutable|sunlnk|sunlink|uappnd|uappend|uchg|uchange|uimmutable|uunlnk|uunlink)]+
Synopsis: List of menu options for bsd file system flags to set
Example:
body perms example
{
bsdflags => { "uappnd","uchg","uunlnk","nodump",
"opaque","sappnd","schg","sunlnk" };
}
Notes:
The BSD Unices (FreeBSD, OpenBSD, NetBSD) and MacOSX have additional
filesystem flags which can be set. Refer to the BSD chflags
documentation for this.
groups’Allowed input range: [a-zA-Z0-9_$.-]+
Synopsis: List of acceptable groups of group ids, first is change target
Example:
body perms example
{
groups => { "users", "administrators" };
}
Notes:
The first named group is the list is the defaul that will be configured if the file does not match an element of the list. The reserved word ‘none’ may be used to match files that are not owned by a registered group. On windows, files do not have file groups associated with them and thus this attribute is ignored.
In CFEngine Nova, ACLs may be used in place for this.
mode’Allowed input range: [0-7augorwxst,+-]+
Synopsis: File permissions (like posix chmod)
Example:
body perms example
{
mode => "a+rx,o+w";
}
Notes:
The mode string may be symbolic or numerical, like chmod. This
is ignored on windows, as the permission model uses ACLs. ACLs are
supported by CFEngine Nova.
owners’Allowed input range: [a-zA-Z0-9_$.-]+
Synopsis: List of acceptable owners or user ids, first is change target
Example:
body perms example
{
owners => { "mark", "wwwrun", "jeang" };
}
Notes:
The first user is the reference value that CFEngine will set the file to if none of the list items matches the true state of the file. The reserved word ‘none’ may be used to match files that are not owned by a registered user.
On windows, users can only take ownership of files, never give
it. Thus, the first user in the list should be the user running the
CFEngine process (usually “Administrator”). Additionally, some
groups may be owners on windows (such as the “Administrators”
group).
rxdirs’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false add execute flag for directories if read flag is set
Example:
body perms rxdirs
{
rxdirs => "false";
}
Notes:
Default behaviour is to set the ‘x’ flag on directories automatically if the ‘r’ flag is specified when specifying multiple files in a single promise. This is ignored on windows, as the permission model uses ACLs.
rename (compound body)Type: (ext body)
disable’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false automatically rename and remove permissions
Default value: false
Example:
body rename example
{
disable => "true";
disable_suffix => ".nuked";
}
Notes:
Disabling a file means making is impotent in the context in which it
has an effect. For executables this means preventing execution, for an
information file it means making the file unreadable.
disable_mode’Allowed input range: [0-7augorwxst,+-]+
Synopsis: The permissions to set when a file is disabled
Example:
body rename example
{
disable_mode => "0600";
}
Notes:
To disable an executable it is not enough to rename it, you should also remove the
executable flag.
disable_suffix’Allowed input range: (arbitrary string)
Synopsis: The suffix to add to files when disabling (.cfdisabled)
Example:
body rename example
{
disable => "true";
disable_suffix => ".nuked";
}
Notes:
To make disabled files in a particular manner, use this string suffix.
The default value is .cf-disabled.
newname’Allowed input range: (arbitrary string)
Synopsis: The desired name for the current file
Example:
body rename example(s)
{
newname => "$(s)";
}
Notes:
rotate’Allowed input range: 0,99
Synopsis: Maximum number of file rotations to keep
Example:
body rename example
{
rotate => "4";
}
Notes:
Used for log rotation. If the file is named foo and the ‘rotate’ attribute is set to ‘4’, as above, then initially foo is copied to foo.1 and the old file foo is zeroed out (that is, the inode of the original logfile does not change, but the original logfile will be empty after the rotation is complete).
The next time the promise is executed, foo.1 will be renamed foo.2, foo is again copied to foo.1 and the old file foo is again zeroed out.
Each time the promise is executed (and typically, the promise would be executed as guarded by time-based or file-size-based classes), the files are copied/zeroed or rotated as above until there are ‘rotate’ numbered files plus the one "main" file. In the example above, the file foo.3 will be renamed foo.4, but the old version of the file foo.4 will be deleted (that is, it "falls off the end" of the rotation).
repositoryType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Name of a repository for versioning
Example:
files: "/path/file" copy_from => source, repository => "/var/cfengine/repository";
Notes:
A local repository for this object, overrides the default.
touchType: (menu option)
Allowed input range:
truefalseyesnoonoff
Synopsis: true/false whether to touch time stamps on file
Example:
files: "/path/file" touch => "true";
Notes:
transformerType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Command (with full path) used to transform current file (no shell wrapper used)
Example:
"/home/mark/tmp/testcopy"
file_select => pdf_files,
transformer => "/usr/bin/gzip $(this.promiser)",
depth_search => recurse("inf");
###################
classes:
"do_update" or => isnewerthan("/etc/postfix/alias",
"/etc/postfix/alias.cdb") };
files:
"/etc/postfix/alias.cdb"
create => true, # Must have this!
transformer => "/usr/sbin/postalias /etc/postfix/alias",
ifvarclass => "do_update";
}
Notes:
A command to execute, usually for the promised file to transform it to something else (but possibly to create the promised file based on a different origin file). The examples above show both types of promises.
In the first example, the promise is made on the file that we wish to transform. If the promised file exists, the transformer will change the file to a compressed version (and the next time CFEngine runs, the promised file will no longer exist, because it now has the ‘.gz’ extension).
In the second example, the promise is made on the file resulting from the transformation (and the promise is conditional on the original file being newer than the result file). In this case, we must specify ‘create => true’. If we do not, then if the promised file is removed, the transformer will not be executed.
Note also that if you use the $(this.promiser)
variable or other variable in this command, and the file object contains
spaces you should quote the variable, e.g.
transformer => "/usr/bin/gzip \"$(this.promiser)\"",
Note also that the transformer does not actually need to change the file. You can, for example, simply report on the existence of files with
transformer => "/bin/echo I found a file named $(this.promiser)",
Be aware that stdout and stderr are redirected by CFEngine, and
will not appear in any output unless you run cf-agent with the
‘-v’ switch (or enable verbose in an outputs promise).
Finally, you should note that the command is not run in a shell - which means that you cannot perform file redirection or create pipelines.
* promises in ‘edit_line’
Most promise bodies belong to one and only one type of promise. The
generic `*' promises bodies can be added to any promise type in
cf-agent, hence the star which means (for this documentation
only) `any'.
The body attributes described below can thus be added to any promise rule in the agent. These promises address matters of a completely general nature – how cfengine behaves as it attempts to keep a promise, comments about the promises etc.
files:
"/etc/passwd" -> "Security team"
perms => p("644"),
action => justcheck,
comment => "This was decided in internal procedures XYZ123";
select_region (compound body)Type: (ext body)
include_start_delimiter’Allowed input range:
truefalseyesnoonoff
Synopsis: Whether to include the section delimiter
Default value: false
Example:
body select_region MySection(x)
{
select_start => "\[$(x)\]";
select_end => "\[.*\]";
include_start_delimiter => "true";
}
Notes:
In a sectioned file, the line that marks the opening of a section is not normally included in the defined region (that is, it is recognized as a delimiter, but it is not included as one of the lines available for editing). Setting this option to true makes it included. e.g. in this example
[My section]
one
two
three
the section does not normally include the line ‘[My section]’.
By setting include_start_delimiter to ‘true’it would be possible
for example, to delete the entire section, including the section header. If
however include_start_delimiter is ‘false’, the contents of
the section could be deleted, but the header would be unaffected by any
delete_lines promises. See the next section on
include_start_delimiter for further details.
History: This attribute was introduced in CFEngine version 3.0.5 (2010)
include_end_delimiter’Allowed input range:
truefalseyesnoonoff
Synopsis: Whether to include the section delimiter
Default value: false
Example:
body select_region BracketSection(x)
{
select_start => "$(x) \{";
select_end => "}";
include_end_delimiter => "true";
}
Notes:
In a sectioned file, the line that marks the end of a section is not normally included in the defined region (that is, it is recognized as a delimiter, but it is not included as one of the lines available for editing). Setting this option to true makes it included. e.g. in this example
/var/log/mail.log {
monthly
missingok
notifempty
rotate 7
}
the section does not normally include the line containing ‘}’.
By setting include_end_delimiter to ‘true’it would be possible
for example, to delete the entire section, including the section trailer. If
however include_end_delimiter is ‘false’, the contents of
the section could be deleted, but the header would be unaffected by any
delete_lines promises.
The use of include_start_delimiter and include_end_delimiter
depend on the type of sections you are dealing with, and what you want to do
with them. Note that sections can be bounded at both the start and end (as
in the example above) or just at the start (as in the sample shown in
include_start_delimiter).
History: This attribute was introduced in CFEngine version 3.0.5 (2010)
select_start’Allowed input range: .*
Synopsis: Regular expression matching start of edit region
Example:
body select_region example(x)
{
select_start => "\[$(x)\]";
select_end => "\[.*\]";
}
Notes:
See also select_end. These delimiters mark out the region
of a file to be edited. In the example, it is assumed that the file
has section markers.
[section 1]
lines.
lines...
[section 2]
lines ....
etc..
The start marker includes the first matched line.
select_end’Allowed input range: .*
Synopsis: Regular expression matches end of edit region from start
Example:
body select_region example(x)
{
select_start => "\[$(x)\]";
select_end => "\[.*\]";
}
Notes:
See also select_start. These delimiters mark out the region
of a file to be edited. In the example, it is assumed that the file
has section markes
[section 1]
lines.
lines...
[section 2]
lines ....
etc..
If you want to match from a starting location to the end of the file (even if
there are other lines matching select_start intervening), then just omit
the select_end promise and the selected region will run to the end of
the file.
delete_lines promises in ‘edit_line’
This promise assures that certain lines matching regular expression
patterns exactly will not be present in a text file. If the lines are
found, the default promise is to remove them (this behavior may be modified
with further pattern matching in delete_select and/or changed with
not_matching).
bundle edit_line example
{
delete_lines:
"olduser:.*";
}
delete_select (compound body)Type: (ext body)
delete_if_startwith_from_list’Allowed input range: .*
Synopsis: Delete line if it starts with a string in the list
Example:
body delete_select example(s)
{
delete_if_startwith_from_list => { @(s) };
}
Notes:
Delete lines from a file if they begin with the sub-strings listed. Note that this determination is made only on promised lines (that is, this attribute modifies the selection criteria, it does not make the initial selection). Therefore, if the file contains the following lines:
start alpha igniter
start beta igniter
init alpha burner
init beta burner
stop beta igniter
stop alpha igniter
stop alpha burner
Then the following promise initially selects the four lines containing
‘alpha’, but is moderated by the delete_select attribute. Thus,
the promise will delete only the first and third lines of the file:
bundle edit_line alpha
{
delete_lines:
".*alpha.*"
delete_select => starters;
}
body delete_select starters
{
delete_if_startwith_from_list => { "begin", "start", "init" };
}
delete_if_not_startwith_from_list’Allowed input range: .*
Synopsis: Delete line if it DOES NOT start with a string in the list
Example:
body delete_select example(s)
{
delete_if_not_startwith_from_list => { @(s) };
}
Notes:
Delete lines from a file unless they start with the sub-strings in the list
given. Note that this determination is made only on promised lines (that is,
this attribute modifies the selection criteria, it does not make the initial
selection).
delete_if_match_from_list’Allowed input range: .*
Synopsis: Delete line if it fully matches a regex in the list
Example:
body delete_select example(s)
{
delete_if_match_from_list => { @(s) };
}
Notes:
Delete lines from a file if the lines completely match any of the regular expressions listed (that is, the regular expression is anchored, See Anchored vs. unanchored regular expressions).
Note that the “match” determination is made only on promised lines (that is, this
attribute modifies the selection criteria, it does not make the initial
selection).
delete_if_not_match_from_list’Allowed input range: .*
Synopsis: Delete line if it DOES NOT fully match a regex in the list
Example:
body delete_select example(s)
{
delete_if_not_match_from_list => { @(s) };
}
Notes:
Delete lines from a file unless the lines completely match any of the regular expressions listed (that is, the regular expressions are anchored, See Anchored vs. unanchored regular expressions).
Note that the “match” determination is made only on promised lines (that is, this
attribute modifies the selection criteria, it does not make the initial
selection).
delete_if_contains_from_list’Allowed input range: .*
Synopsis: Delete line if a regex in the list match a line fragment
Example:
body delete_select example(s)
{
delete_if_contains_from_list => { @(s) };
}
Notes:
Delete lines from a file if they contain the sub-strings listed.
Note that this determination is made only on promised lines (that is, this
attribute modifies the selection criteria, it does not make the initial
selection).
delete_if_not_contains_from_list’Allowed input range: .*
Synopsis: Delete line if a regex in the list DOES NOT match a line fragment
Example:
body delete_select discard(s)
{
delete_if_not_contains_from_list => { "substring1", "substring2" };
}
Notes:
Delete lines from the file which do not contain the sub-strings listed. Note that this determination is made only on promised lines (that is, this attribute modifies the selection criteria, it does not make the initial selection).
not_matchingType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false negate match criterion
Example:
delete_lines: # edit /etc/passwd - account names that are not "mark" or "root" "(mark|root):.*" not_matching => "true";
Notes:
The negation of an expression (for convenience).
insert_lines promises in ‘edit_line’
This promise is part of the line-editing model. It inserts lines into the file at a specified location. The location is determined by body-attributes. The promise object referred to can be a literal line of a file-reference from which to read lines.
insert_lines:
"literal line or file reference"
location => location_body,
...;
|
body common control
{
any::
bundlesequence => {
example
};
}
#######################################################
bundle agent example
{
files:
"/var/spool/cron/crontabs/root"
edit_line => addline;
}
#######################################################
# For the library
#######################################################
bundle edit_line addline
{
insert_lines:
"0,5,10,15,20,25,30,35,40,45,50,55 * * * * /var/cfengine/bin/cf-execd -F";
}
By parameterizing the editing bundle, one can make generic and reusable editing bundles.
Note, when inserting multiple lines anchored to a particular place in a file, be careful with your intuition. If your intention is to insert a set of lines in a given order after a marker, then the following is incorrect:
bundle edit_lines x
{
insert_lines:
"line one" location => myloc;
"line two" location => myloc;
}
body location myloc
{
select_line_matching => "# Right here.*";
before_after => "after";
}
This will reverse the order of the lines and will not converge, since
the anchoring after the marker applies independently for each new
line. This is not a bug, but an error of logic.
What was probably intended was to add multiple ordered lines after the marker, which should be a single correlated promise.
bundle edit_lines x
{
insert_lines:
"line one$(const.n)line two" location => myloc;
}
Or:
bundle edit_lines x
{
insert_lines:
"line one
line two" location => myloc;
}
expand_scalarsType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: Expand any unexpanded variables
Example:
body common control
{
bundlesequence => { "testbundle" };
}
########################################################
bundle agent testbundle
{
files:
"/home/mark/tmp/file_based_on_template"
create => "true",
edit_line => ExpandMeFrom("/tmp/source_template");
}
########################################################
bundle edit_line ExpandMeFrom(template)
{
insert_lines:
"$(template)"
insert_type => "file",
expand_scalars => "true";
}
Notes:
A way of incorporating templates with variable expansion into file operations. Variables should be named and scoped appropriately for the bundle in which this promise is made. i.e. you should qualify the variables with the bundle in which they are defined:
$(bundle.variable) $(sys.hostname) $(mon.www_in)
In cfengine 2 editfiles this was called ‘ExpandVariables’.
insert_typeType: (menu option)
Allowed input range:
literalstringfilepreserve_block
Default value: literal
Synopsis: Type of object the promiser string refers to
Example:
bundle edit_line lynryd_skynyrd
{
vars:
"keepers" slist => { "Won't you give me", "Gimme three steps" };
insert_lines:
"And you'll never see me no more"
insert_type => "literal"; # the default
"/song/lyrics"
insert_type => "file", # read selected lines from /song/lyrics
insert_select => keep("@{keepers}");
}
body insert_select keep(s)
{
insert_if_startwith_from_list => { "@(s)" };
}
This will ensure that the following lines are inserted into the promised file:
And you'll never see me no more Gimme three steps, Mister Gimme three steps towards the door Gimme three steps
Notes:
The default is to treat the promiser as a literal string of convergent
lines (the values literal and string are synonymonous).
The value file is used to tell cfengine that the string is non-literal
and should be interpreted as a filename from which to import lines, see
insert_select
The default behaviour assumes that multi-line entries are not ordered specifically, and should be treated as a collection of lines of text and not as a single unbroken object. If the option ‘preserve_block’ is used, then CFEngine will not break up multiple lines into individual, non-ordered objects, so that the block of text will be preserved. However, due to convergence constraints, if all the lines exist at the start, CFEngine will not see the need to add any new text. If any one of the lines is missing from the block, then the whole block will be added as a single entity. (This is the only way to achieve convergent behaviour in block editing.)
insert_select (compound body)Type: (ext body)
insert_if_startwith_from_list’Allowed input range: .*
Synopsis: Insert line if it starts with a string in the list
Example:
body insert_select example
{
insert_if_startwith_from_list => { "find_me_1", "find_me_2" };
}
Notes:
The list contains literal strings to search for in the secondary
file (the file being read via the insert_type attribute, not
the main file being edited). If a string with matching starting
characters is found, then that line from the secondary file will
be inserted at the present location in the primary file.
insert_if_startswith_from_list is ignored unless insert_type is file
(see insert_type in insert_lines),
or the promiser is a multi-line block.
insert_if_not_startwith_from_list’Allowed input range: .*
Synopsis: Insert line if it DOES NOT start with a string in the list
Example:
body insert_select example
{
insert_if_not_startwith_from_list => { "find_me_1", "find_me_2" };
}
Notes:
The complement of insert_if_startwith_from_list. If the start of a
line does not match one of the strings, that line is inserted into the
file being edited.
insert_if_not_startswith_from_list is ignored unless insert_type is file
(see insert_type in insert_lines),
or the promiser is a multi-line block.
insert_if_match_from_list’Allowed input range: .*
Synopsis: Insert line if it fully matches a regex in the list
Example:
body insert_select example
{
insert_if_match_from_list => { ".*find_.*_1.*", ".*find_.*_2.*" };
}
Notes:
The list contains literal strings to search for in the secondary file (the file
being read via the insert_type attribute, not the main file being edited).
If the regex matches a complete line of the file,
that line from the secondary file will be inserted at the present location
in the primary file. That is, the regex's in the list are anchored
See Anchored vs. unanchored regular expressions).
insert_if_match_from_list is ignored unless insert_type is file
(see insert_type in insert_lines),
or the promiser is a multi-line block.
insert_if_not_match_from_list’Allowed input range: .*
Synopsis: Insert line if it DOES NOT fully match a regex in the list
Example:
body insert_select example
{
insert_if_not_match_from_list => { ".*find_.*_1.*", ".*find_.*_2.*" };
}
Notes:
The complement of insert_if_match_from_list. If the line does not
match a line in the secondary file, it is inserted into the file being edited.
insert_if_not_match_from_list is ignored unless insert_type is file
(see insert_type in insert_lines),
or the promiser is a multi-line block.
insert_if_contains_from_list’Allowed input range: .*
Synopsis: Insert line if a regex in the list match a line fragment
Example:
body insert_select example
{
insert_if_contains_from_list => { "find_me_1", "find_me_2" };
}
Notes:
The list contains literal strings to search for in the secondary file (the file
being read via the insert_type attribute, not the main file being edited).
If the string is found in a line of the file, that line from the secondary
file will be inserted at the present location in the primary file.
insert_if_contains_from_list is ignored unless insert_type is file
(see insert_type in insert_lines),
or the promiser is a multi-line block.
insert_if_not_contains_from_list’Allowed input range: .*
Synopsis: Insert line if a regex in the list DOES NOT match a line fragment
Example:
body insert_select example
{
insert_if_not_contains_from_list => { "find_me_1", "find_me_2" };
}
Notes:
The complement of insert_if_contains_from_list. If the line is not
found in the secondary file, it is inserted into the file being edited.
insert_if_not_contains_from_list is ignored unless insert_type is file
(see insert_type in insert_lines),
or the promiser is a multi-line block.
location (compound body)Type: (ext body)
before_after’Allowed input range:
beforeafter
Synopsis: Menu option, point cursor before of after matched line
Default value: after
Example:
body location append
{
#...
before_after => "before";
}
Notes:
Determines whether an edit will occur before or after the currently
matched line.
first_last’Allowed input range:
firstlast
Synopsis: Menu option, choose first or last occurrence of match in file
Default value: last
Example:
body location example
{
first_last => "last";
}
Notes:
In multiple matches, decide whether the first or last occurrence of
the matching pattern in the case affected by the change. In principle
this could be generalized to more cases but this seems like a fragile
quality to evaluate, and only these two cases are deemed of
reproducible significance.
select_line_matching’Allowed input range: .*
Synopsis: Regular expression for matching file line location
Example:
body match_value example
{
select_line_matching => "Expression match.* whole line";
}
Notes:
The expression must match a whole line, not a fragment within a line (that is, it is anchored See Anchored vs. unanchored regular expressions).
This attribute is mutually exclusive of select_line_number.
whitespace_policyType: (option list)
Allowed input range:
ignore_leadingignore_trailingignore_embeddedignore_embeddedexact_match
Synopsis: Criteria for matching and recognizing existing lines
Example:
bundle edit_line Insert(service, filename)
{
insert_lines:
"$(service).* $(filename)"
whitespace_policy => { "ignore_trailing", "ignore_embedded" };
}
Notes:
The white space matching policy applies only to insert_lines,
as a convenience. It works by rewriting the insert string as a regular
expression when matching lines (that is, when determining if the line is
already in the file), but leaving the string as specified when
actually inserting it.
Simply put, the `does this line exist' test will be changed to a
regexp match. The line being tested will optionally have "\s*"
prepended or appended if ignore_leading or
ignore_trailing is specified, and if ignore_imbedded is
used then all embedded whitespaces are replaced with ‘\s+’. You may
specify more than one whitespace_policy – they are additive.
Any regular expression meta-characters that exist in your input line will be escaped, so that you can still, for example, safely insert a line like ‘"authpriv.* /var/log/something"’ into your syslog config file.
History: This attribute was introduced in CFEngine version 3.0.5 (2010)
Default value:
exact_match (so unless you use this new attribute, your
insert_line promises should behave as before.
field_edits promises in ‘edit_line’
Certain types of text file (e.g. the passwd and group
files in Unix) are tabular in nature, with field separators
(e.g. ‘:’ or ‘,’). This promise assumes a parameterizable model
for editing the fields of such files, using a regular expression to
separate major fields and a character to separate sub-fields. First
you match the line with a regular expression. The regular
expression must match the entire line (that is, it is anchored
See Anchored vs. unanchored regular expressions). Then a
field_edits body describes the separators for fields and one
level of sub-fields, along with policies for editing these fields, ordering
the items within them etc.
field_edits:
"regex matching line"
edit_field => body;
|
bundle agent example
{
vars:
"userset" slist => { "one-x", "two-x", "three-x" };
files:
"/tmp/passwd"
create => "true",
edit_line => SetUserParam("mark","6","/set/this/shell");
"/tmp/group"
create => "true",
edit_line => AppendUserParam("root","4","@(userset)");
}
########################################################
bundle edit_line SetUserParam(user,field,val)
{
field_edits:
"$(user):.*"
# Set field of the file to parameter
edit_field => col(":","$(field)","$(val)","set");
}
########################################################
bundle edit_line AppendUserParam(user,field,allusers)
{
vars:
"val" slist => { @(allusers) };
field_edits:
"$(user):.*"
# Set field of the file to parameter
edit_field => col(":","$(field)","$(val)","alphanum");
}
########################################
# Bodies
########################################
body edit_field col(split,col,newval,method)
{
field_separator => "$(split)";
select_field => "$(col)";
value_separator => ",";
field_value => "$(newval)";
field_operation => "$(method)";
extend_fields => "true";
}
Field editing allows us to edit tabular files in a unique way, adding and removing data from addressable fields. The passwd and group files are classic examples of tabular files, but there are many ways to use this feature, e.g. edit a string
VARIABLE="one two three"
View this line as a tabular line separated by ‘"’ and with sub-separator given by the space.
edit_field (compound body)Type: (ext body)
allow_blank_fields’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false allow blank fields in a line (do not purge)
Default value: false
Example:
body edit_field example
{
# ...
allow_blank_fields => "true";
}
Notes:
When editing a file using the field or column model, blank fields, especially
at the start and end are generally discarded. If this is set to true, cfengine
will retain the blank fields and print the appropriate number of field separators.
extend_fields’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false add new fields at end of line if necessary to complete edit
Default value: false
Example:
body edit_field example
{
extend_fields => "true";
}
Notes:
If a user specifies a field that does not exist, because there are not
so many fields, this allows the number of fields to be extended.
Without this setting, cfengine will issue an error if a non-existent field
is referenced.
Blank fields in a tabular file can be eliminated or kept depending
in this setting. If in doubt, set this to true.
field_operation’Allowed input range:
prependappendalphanumdeleteset
Synopsis: Menu option policy for editing subfields
Default value: none
Example:
body edit_field example
{
field_operation => "append";
}
Notes:
The method by which to edit a field in multi-field/column editing of tabular files. The methods mean:
‘append’ - append the specified value to the end of the field/column, separating (potentially) multiple values with ‘value_separator’
‘prepend’ - prepend the specified value at the beginning of the field/column, separating (potentially) multiple values with ‘value_separator’
‘alphanum’ - insert the specified value into the field/column, keeping all the values (separated by ‘value_separator’) in alphanumerically sorted order)
‘set’ - replace the entire field/column with the specified value
‘delete’ - delete the specified value (if present) in the specified field/column
Default value:
append
field_separator’Allowed input range: .*
Synopsis: The regular expression used to separate fields in a line
Default value: none
Example:
body edit_field example
{
field_separator => ":";
}
Notes:
Most tabular files are separated by simple characters, but by allowing
a general regular expression one can make creative use of this model to
edit all kinds of line-based text files.
field_value’Allowed input range: .*
Synopsis: Set field value to a fixed value
Example:
body edit_field example(s)
{
field_value => "$(s)";
}
Notes:
Set a field to a constant value, e.g. reset the value to a constant
default, empty the field, or set it fixed list.
select_field’Allowed input range: 0,99999999
Synopsis: Integer index of the field required 0..n (default starts from 1)
Example:
body field_edits example
{
select_field => "5";
}
Notes:
Numbering starts from 1 (not from 0).
start_fields_from_zero’Allowed input range:
truefalseyesnoonoff
Synopsis: If set, the default field numbering starts from 0
Example:
body edit_field col(split,col,newval,method)
{
field_separator => "$(split)";
select_field => "$(col)";
value_separator => ",";
field_value => "$(newval)";
field_operation => "$(method)";
extend_fields => "true";
allow_blank_fields => "true";
start_fields_from_zero => "true";
}
Notes:
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
The numbering of fields is a matter for consistency and convention.
Arrays are usually thought to start with first index equal to zero (0),
but the first column in a file would normally be 1. By setting this option,
you can tell CFEngine that the first column should be understood as number 0
instead, for consistency with other array functions.
value_separator’Allowed input range: ^.$
Synopsis: Character separator for subfields inside the selected field
Default value: none
Example:
body field_edit example
{
value_separator => ",";
}
Notes:
For example, elements in the group file are separated by ‘:’, but the lists of users in these fields are separated by ‘,’.
replace_patterns promises in ‘edit_line’
This promise refers to arbitrary text patterns in a file. The pattern is expressed as a regular expression and must be compatible with the default model for regular expressions on your system. The default model is PCRE (Perl Compatible Regular Expressions) if available.
replace_patterns:
"search pattern"
replace_with => replace_body,
...;
|
bundle edit_line upgrade_cfexecd
{
replace_patterns:
"cfexecd" replace_with => value("cf-execd");
}
########################################
body replace_with value(x) # defined in cfengine_stdlib.cf
{
replace_value => "$(x)";
occurrences => "all";
}
This is a straightforward search and replace function. Only the portion of the line that matches the pattern in the promise will be replaced - the remainder of the line will not be affected. You can also use PCRE lookbehind and lookahead patterns to restrict the lines upon which the pattern will match.
NOTE: In replace_patterns promises, the regular expression may
match a line fragment, that is, it is unanchored
See Anchored vs. unanchored regular expressions.
replace_with (compound body)Type: (ext body)
occurrences’Allowed input range:
allfirst
Synopsis: Menu option to replace all occurrences or just first (NB the latter is non-convergent)
Default value: all
Example:
body replace_with example
{
occurrences => "first"; # Warning! Using "first" is non-convergent
}
Notes:
A policy for string replacement.
Default value:
The default value is "all". Using "first" is generally unwise, as it is
possibly non-convergent (it will change a different matching string each time
the promise is executed, and may not "catch up" with whatever external action
is altering the text the promise applies to).
replace_value’Allowed input range: .*
Synopsis: Value used to replace regular expression matches in search
Example:
body replace_with example(s)
{
replace_value => "$(s)";
}
Notes:
interfaces promises in ‘agent’
Interfaces promises describe the configurable aspects relating to network interfaces. Most workstations and servers have only a single network interface, but routers and multi-homed hosts often have multiple interfaces. Interface promises include attributes such as the IP address identity, assumed netmask and routing policy in the case of multi-homed hosts. For virtual machines and hosts, the list of interfaces can be quite large.
interfaces:
"interface name"
tcp_ip => tcp_ip_body,
...;
|
For future use.
For future use.
tcp_ip (compound body)Type: (ext body)
ipv4_address’Allowed input range: [0-9.]+/[0-4]+
Synopsis: IPv4 address for the interface
Example:
body tcp_ip example
{
ipv4_address => "123.456.789.001";
}
Notes:
The address will be checked and if necessary set. Today few hosts will
be managed in this way: address management will be handled by other services
like DHCP.
ipv4_netmask’Allowed input range: [0-9.]+/[0-4]+
Synopsis: Netmask for the interface
Example:
body tcp_ip example
{
ipv4_netmask => "255.255.254.0";
}
Notes:
In many cases the CIDR form of address will show the netmask as ‘/23’, but
this offers and `old style' alternative.
ipv6_address’Allowed input range: [0-9a-fA-F:]+/[0-9]+
Synopsis: IPv6 address for the interface
Example:
"eth0"
ipv6_address => "2001:700:700:3:211:63ff:feeb:5d18/64";
Notes:
methods promises in ‘agent’
Methods are compound promises that refer to whole bundles of promises. Methods may be parameterized. Methods promises are written in a form that is ready for future development. The promiser object is an abstract identifier that refers to a collection (or pattern) of lower level objects that are affected by the promise-bundle. Since the use of these identifiers is for the future, you can simply use any string here for the time being.
methods:
"any"
usebundle => method_id("parameter",...);
|
Methods are useful for encapsulating repeatedly used configuration issues and iterating over parameters.
In cfengine 2 methods referred to separate sub-programs executed as separate processes. Methods are now implemented as bundles that are run inline.
bundle agent example
{
vars:
"userlist" slist => { "mark", "jeang", "jonhenrik", "thomas", "eben" };
methods:
"any" usebundle => subtest("$(userlist)");
}
###########################################
bundle agent subtest(user)
{
commands:
"/bin/echo Fix $(user)";
reports:
linux::
"Finished doing stuff for $(user)";
}
Methods offer powerful ways to encapsulate multiple issues pertaining to a set of parameters.
Because a method is just an encapsulation, there is a subtlety about
how to interpret a successful method invocation. Before version 3.1.0,
a method was considered repaired if executed (like commands),
however this led to unnecessary logging of executions, even if not
actual encapsulated promise was kept. In version 3.1.0 this has been
changed so that a method promise is considered kept if the method
is expanded. A method promise is thus never considered repaired.
Starting from version 3.1.0, methods may be specified using variables. Care should be exercised when using this approach. In order to make the function call uniquely classified, CFEngine requires the promiser to contain the variable name of the method if the variable is a list.
bundle agent default
{
vars:
"m" slist => { "x", "y" };
"p" string => "myfunction";
methods:
"set of $(m)" usebundle => $(m) ("one");
"any" usebundle => $(p)("two");
}
usebundleType: (ext bundle) (Separate Bundle)
outputs promises in ‘agent’
Outputs promises are only available in commercial editions of Cfengine. They allow promises to make meta-promises about their output levels. More simply, you can switch on ‘verbose’ or ‘inform’ level output to named promises, or whole bundles for debugging purposes.
If you use the ‘-I’ or ‘-v’ command line options, then CFEngine will generate informative or verbose output for all the promises it is processing. This can be a daunting collection of data when dealing with even a medium-sized set of promises.
Output promises enable you to selectively debug individually named promises (or bundles), thus eliminating the need for scanning unrelated CFEngine output.
outputs:
"run_agent"; # Promise handle, verbose output
"web_server" # Bundle handle, inform output
output_level => "inform",
promiser_type => "bundle";
The default behaviour is to print verbose output for listed promise handles; See handle in *, for bundle names.
History This was introduced in Nova version 1.1.3. (2010)
output_levelType: (menu option)
Allowed input range:
verbosedebuginform
Default value: verbose
Synopsis: Output level to observe for the named promise or bundle (meta-promise)
Example:
commands:
"/etc/init.d/agent start"
handle => "run_agent",
ifvarclass => "need_to_run_agent";
outputs:
"run_agent"
output_level => "inform";
Notes:
With no attribute, verbose output is assumed.
promiser_typeType: (menu option)
Allowed input range:
promisebundle
Default value: promise
Synopsis: Output level to observe for the named promise or bundle (meta-promise)
Example:
outputs:
"web_server"
promiser_type => "bundle";
Notes:
Without this attribute, CFEngine assumes a list of promises to report on (because there may be a promise for a thing that has the same name as a bundle, you must explicitly specify when you want to report on a bundle of promises).
packages promises in ‘agent’
vars:
"match_package" slist => {
"apache2",
"apache2-mod_php5",
"apache2-prefork",
"php5"
};
packages:
"$(match_package)"
package_policy => "add",
package_method => yum;
|
Software packaging is a core paradigm in operating system release management today, and cfengine supports a generic approach to integration with native operating support for packaging. Package promises allow cfengine to make promises the state of software packages conditionally, given the assumption that a native package manager will perform the actual manipulations. Since no agent can make unconditional promises about another, this is the best that can be achieved.
Packages are treated as black-boxes with three labels:
Package managers are treated as black boxes that may support some or all of the following promise types:
If these services are promised by a package manager, cf-agent
promises to use the service and encapsulate it within the overall
cfengine framework.
Domain knowledge
CFEngine does not maintain operating system specific expert knowledge internally, rather it uses a generic model for dealing with promises about packages (which depend on the behaviour of an external package manager). The approach is to define package system details in body-constraints that can be written once and for all, for each package system.
Package promises are like commands promises in the sense that
cfengine promises nothing about the outcome of executing a
command. All it can promise is to interface with it, starting it and
using the results in good faith. Packages are basically `outsourced',
to invoke IT parlance.
The possibility of a cfengine package format that enables more guaranteeable
behaviour for special purposes has not been excluded for the future,
but in any case cf-agent must support native package formats
used by operating system maintainers as these are a core part of modern
operating systems.
Behaviour
A package promise consists of a name, a version and an architecture, (n,v,a), and behaviour to be promised about packages that match criteria based on these. The components (n,v,a) can be determined in one of two different ways:
packages:
"mypackage"
package_policy => "add",
package_method => rpm,
package_select => ">=",
package_architectures => { "x86_64", "i586" },
package_version => "1.2.3";
package_list_name_regex => "[^|]+\|[^|]+\|\s+([^\s|]+).*";
package_list_version_regex => "[^|]+\|[^|]+\|[^|]+\|\s+([^\s|]+).*";
package_list_arch_regex => "[^|]+\|[^|]+\|[^|]+\|[^|]+\|\s+([^\s]+).*";
When scanning a list of installed packages different managers present the information (n,v,a) in quite different forms and pattern extraction is necessary. When making a promise about a specific package, the cfengine user may choose one or the other model.
Smart and dumb package systems
Package managers vary enormously in their capabilities and in the kinds of promises they make. There are broadly two types
Normal ordering for packages is the following:
Promise repair logic
We can discuss package promise repair in the following table.
bundle agent packages
{
vars:
# Test the simplest case -- leave everything to the yum smart manager
"match_package" slist => {
"apache2",
"apache2-mod_php5",
"apache2-prefork",
"php5"
};
packages:
"$(match_package)"
package_policy => "add",
package_method => yum;
}
Packages promises can be very simple if the package manager is of the smart variety that handles details for you. If you need to specify architecture and version numbers of packages, this adds some complexity, but the options are flexible and designed for maximal adaptability.
Patching
Some package systems also support the idea of `patches'. These might be formally different objects to packages. A patch might contain material for several packages and be numbered differently. When you select patching-policy the package name (promiser) can be a regular expression that will match possible patch names, otherwise identifying specific patches can be cumbersome.
Note that patching is a subtle business. There is no simple way using the patch settings to install `all new system patches'. Here's why:
If we specify the name of a patch, then cfengine will try to see if it exists and/or is installed. If it exists in the pending list, it will be installed. If it exists in the installed list it will not be installed. Now consider the pattern ‘.*’. This will match any installed package, so cfengine will assume the relevant patch has been installed already. On the other hand, the pattern ‘no match’ will not match an installed patch, but it will not match a named patch either.
Some systems provide a command to do this, which can be specified
without specific patch arguments. If so, that command can be called
periodically under commands. The main purposes of patching
body items are:
Installers without package/patch arguments
CFEngine supports the syntax ‘$’ at the end of a command to mean that no package name arguments should be used or appended after the dollar. This is because some commands require a list of packages, while others require an empty list. The default behaviour is to try to append the name of one or more packages to the command, depending on whether the policy is for individual or bulk installation.
package_architecturesType: slist
Allowed input range: (arbitrary string)
Synopsis: Select the architecture for package selection
Example:
packages:
"$(exact_package)"
package_policy => "add",
package_method => rpm,
package_architectures => { "x86_64" };
Notes:
It is possible to specify a list of packages of different architectures if it is desirable to install multiple architectures on the host. If no value is specified, cfengine makes no promise about the result; the package manager's behaviour prevails.
package_method (compound body)Type: (ext body)
package_add_command’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Command to install a package to the system
Example:
body package_method rpm
{
package_add_command => "/bin echo /bin/rpm -i ";
}
Notes:
This command should install a package when appended with the package
reference id, formed using the package_name_convention, using
the model of (name,version,architecture). If
package_file_repositories is specified, the package reference
id will include the full path to a repoistory containing the package.
Package managers generally expect the name of a package to be passed
as a parameter. However, in some cases we do not need to pass the name
of a particular package to the command. Ending the command string with
‘$’ prevents CFEngine from appending the package name to the
string.
package_arch_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract package architecture string
Example:
body package_method rpm
{
package_list_arch_regex => "[^.]+\.([^.]+)";
}
Notes:
This is for use when extracting architecture from the name of the
promiser, i.e. when the architecture is not specified using the
package_architectures list. It is a regular expression that
contains exactly one parenthesized back reference which marks the
location in the promiser at which the architecture is specified.
The regex may match a portion of the string (i.e., it is unanchored
See Anchored vs. unanchored regular expressions).
If no architecture is specified for the given package manager, then
do not define this.
package_changes’Allowed input range:
individualbulkbulk_no_names
Synopsis: Menu option - whether to group packages into a single aggregate command
Example:
body package_method rpm
{
package_changes => "bulk";
}
Notes:
This indicate whether the package manager is capable of handling
package operations in bulk, i.e. with by given multiple arguments. If
this is set to ‘bulk’ then multiple arguments will be passed to
the package commands. If set to ‘individual’ packages will be
handled one by one. This might add a significant overhead to the
operations, and also affect the ability of the operating system's
package manager to handle dependencies.
package_delete_command’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Command to remove a package from the system
Example:
body package_method rpm
{
package_delete_command => "/bin/rpm -e --nodeps";
}
Notes:
The command that deletes a package from the system when appended with
the package reference identifier specified by
package_name_convention.
Package managers generally expect the name of a package to be passed
as a parameter. However, in some cases we do not need to pass the name
of a particular package to the command. Ending the command string with
‘$’ prevents CFEngine from appending the package name to the
string.
package_delete_convention’Allowed input range: (arbitrary string)
Synopsis: This is how the package manager expects the package to be referred to in the deletion part of a package update, e.g. $(name)
Example:
body package_method freebsd
{
package_file_repositories => { "/path/to/packages" };
package_name_convention => "$(name)-$(version).tbz";
package_delete_convention => "$(name)-$(version)";
}
Notes:
This attribute is used when package_policy is ‘delete’, or
package_policy is ‘update’ and package_file_repositories is set and
package_update_command is not set. It is then used to
set the pattern for naming the package in the way expected by the
package manager during the deletion of existing packages.
Three special variables are defined from the extracted data, in a
private context for use: ‘$(name)’, ‘$(version)’ and
‘$(arch)’. ‘version’ and ‘arch’ is the version and arch
(if package_list_arch_regex is given) of the already installed
package. Additionally, if package_file_repositories is defined,
‘$(firstrepo)’ can be prepended to expand the first repository
containing the package, e.g. ‘$(firstrepo)$(name)-$(version)-$(arch).msi’.
If this is not defined, it defaults to the value of
package_name_convention.
package_file_repositories’Allowed input range: (arbitrary string)
Synopsis: A list of machine-local directories to search for packages
Example:
body package_method filebased
{
package_file_repositories => { "/package/repos1", "/packages/repos2" };
}
Notes:
If specified, cfengine will assume that the package installation occurs by filename and will
search the named paths for a package matching the pattern package_name_convention.
If found the name will be prefixed to the package name in the package commands.
package_installed_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression which matches packages that are already installed
Example:
body package_method yum
{
package_installed_regex => ".*installed.*";
}
Notes:
This regular expression must match complete lines in the output
of the list command that are actually installed packages (that is,
the regex is anchored See Anchored vs. unanchored regular expressions).
If all the lines match then the regex can be set of ‘.*’, however
most package systems output prefix lines and a variety of human
padding that needs to be ignored.
package_list_arch_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract package architecture string
Example:
body package_method rpm
{
package_list_arch_regex => "[^|]+\|[^|]+\|[^|]+\|[^|]+\|\s+([^\s]+).*";
}
Notes:
A regular expression that contains exactly one parenthesized back
reference which marks the location in the listed package at which
the architecture is specified. The regular expression may match a
portion of the string (that is, it is unanchored
See Anchored vs. unanchored regular expressions). If no architecture
is specified for the given package manager, then do not define this
regex.
package_list_command’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Command to obtain a list of available packages
Example:
body package_method rpm
{
package_list_command => "/bin/rpm -qa --queryformat \"%{name} %{version}-%{release}\n\"";
}
Notes:
This command should provide a complete list of the packages installed
on the system. It might also list packages that are not
installed. Those should be filtered out using the
package_installed_regex.
Package managers generally expect the name of a package to be passed as a parameter. However, in some cases
we do not need to pass the name of a particular package to the command. Ending the command string with ‘$’
prevents CFEngine from appending the package name to the string.
package_list_name_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract package name string
Example:
body package_method rpm
{
package_list_name_regex => "([^\s]+).*";
}
Notes:
A regular expression that contains exactly one parenthesized back
reference which marks the name of the package from the package
listing. The regular expression may match a portion of the string
(that is, it is unanchored See Anchored vs. unanchored regular expressions).
package_list_update_command’Allowed input range: (arbitrary string)
Synopsis: Command to update the list of available packages (if any)
Example:
body package_method xyz
{
debian|ubuntu::
package_list_update_command => "/usr/bin/apt-get update";
package_list_update_ifelapsed => "240"; # 4 hours
}
Notes:
Not all package managers update their list information from source
automatically. This command allows a separate update command to be executed at
intervals determined by package_list_update_ifelapsed.
package_list_update_ifelapsed’Allowed input range: -99999999999,9999999999
Synopsis: The ifelapsed locking time in between updates of the package list
Example:
body package_method xyz
{
debian|ubuntu::
package_list_update_command => "/usr/bin/apt-get update";
package_list_update_ifelapsed => "240"; # 4 hours
}
Notes:
Not all package managers update their list information from source
automatically. This command allows a separate update command to be executed at
intervals determined by package_list_update_ifelapsed.
package_list_version_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract package version string
Example:
body package_method rpm
{
package_list_version_regex => "[^\s]+ ([^.]+).*";
}
Notes:
This regular expression should containe exactly one parenthesized
back-reference that marks the version string of packages listed as
installed. The regular expression may match a portion of the string
(that is, it is unanchored See Anchored vs. unanchored regular expressions)
package_name_convention’Allowed input range: (arbitrary string)
Synopsis: This is how the package manager expects the package to be referred to, e.g. $(name).$(arch)
Example:
body package_method rpm
{
package_name_convention => "$(name).$(arch).rpm";
}
Notes:
This sets the pattern for naming the package in the way expected by
the package manager. Three special variables are defined from the
extracted data, in a private context for use: ‘$(name)’,
‘$(version)’ and ‘$(arch)’.
Additionally, if package_file_repositories is defined,
‘$(firstrepo)’ can be prepended to expand the first repository
containing the package, e.g. ‘$(firstrepo)$(name)-$(version)-$(arch).msi’.
When package_policy is ‘update’, and
package_file_repositories is specified,
package_delete_convention may be used to specify a different
convention for the delete command.
If this is not defined, it defaults to the value ‘$(name)’.
package_name_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract package name string
Example:
body package_method rpm
{
package_name_regex => "([^\s]).*";
}
Notes:
This regular expression is only used when the promiser contains
not only the name of the package, but its version and archiecture
also. In that case, this expression should contain a single parenthesized
back-reference to extract the name of the package from the string. The
regex may match a portion of the string (that is, it is unanchored
See Anchored vs. unanchored regular expressions)
package_noverify_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression to match verification failure output
Example:
body package_method xyz
{
# package_noverify_regex => ".*problem.*";
package_noverify_regex => ".*[^\s].*"; # some non-zero output
}
Notes:
A regular expression to match output from a package verification command. If the
output string matches this expression, the package is deemed broken. The regex
must match the entire line (that is, it is anchored
See Anchored vs. unanchored regular expressions)
package_noverify_returncode’Allowed input range: -99999999999,9999999999
Synopsis: Integer return code indicating package verification failure
Example:
body package_method xyz
{
package_noverify_returncode => "-1";
}
Notes:
For use if a package verification command uses the return code as the signal
for a failed package verification.
package_patch_arch_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract update architecture string
Example:
body package_method zypper
{
package_patch_arch_regex => "";
}
Notes:
A few package managers keep a separate notion of patches, as opposed to package updates.
OpenSuSE, for example, is one of these. This provide an analogous command struct to the
packages for patch updates. The regular expression must match the entire line (that is,
it is anchored See Anchored vs. unanchored regular expressions).
package_patch_command’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Command to update to the latest patch release of an installed package
Example:
body package_method zypper
{
package_patch_command => "/usr/bin/zypper -non-interactive patch";
}
Notes:
If the package manager supports patching, this command should patch
a named package. If only patching of all packages is supported then
consider running that as a batch operation in
commands. Alternatively one can end the command string with a
‘$’ symbol, which cfengine will interpret as an instruction to
not append package names.
Package managers generally expect the name of a package to be passed
as a parameter. However, in some cases we do not need to pass the name
of a particular package to the command. Ending the command string with
‘$’ prevents CFEngine from appending the package name to the
string.
package_patch_installed_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression which matches packages that are already installed
Example:
body package_method zypper
{
package_patch_installed_regex => ".*(Installed|Not Applicable).*";
}
Notes:
A few package managers keep a separate notion of patches, as opposed to package updates.
OpenSuSE, for example, is one of these. This provide an analogous command struct to the
packages for patch updates. The regular expression must match the entire string (that is,
it is anchored See Anchored vs. unanchored regular expressions).
package_patch_list_command’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Command to obtain a list of available patches or updates
Example:
package_patch_list_command => "/usr/bin/zypper patches";
Notes:
This command, if it exists at all, is presumed to generate a list of available patches in a format analogous to (but not necessarily the same as) the package-list command, of patches that are available on the system. Patches might formally be available in the packagae manager's view, but if they have already been installed, cfengine will ignore them.
Package managers generally expect the name of a package to be passed
as a parameter. However, in some cases we do not need to pass the name
of a particular package to the command. Ending the command string with
‘$’ prevents CFEngine from appending the package name to the
string.
package_patch_name_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract update name string
Example:
body package_method zypper
{
package_patch_name_regex => "[^|]+\|\s+([^\s]+).*";
}
Notes:
A few package managers keep a separate notion of patches, as opposed to package updates.
OpenSuSE, for example, is one of these. This provide an analogous command struct to the
packages for patch updates. The regular expression may match a partial string (that is,
it is unanchored See Anchored vs. unanchored regular expressions).
package_patch_version_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract update version string
Example:
body package_method zypper
{
package_patch_version_regex => "[^|]+\|[^|]+\|\s+([^\s]+).*";
}
Notes:
A few package managers keep a separate notion of patches, as opposed to package updates.
OpenSuSE, for example, is one of these. This provide an analogous command struct to the
packages for patch updates. The regular expression may match a partial string (that is,
it is unanchored See Anchored vs. unanchored regular expressions).
package_update_command’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Command to update to the latest version a currently installed package
Example:
body package_method zypper
{
package_update_command => "/usr/bin/zypper -non-interactive update";
}
Notes:
If supported this should be a command that updates the version of a
single currently installed package. If only bulk updates are
supported, consider running this as a single command under
commands. The package reference id is appended, with the
pattern of package_name_convention.
When package_file_repositories is specified, the package
reference id will include the full path to a repoistory containing the
package. If package_policy is ‘update’, and this command
is not specified, the package_delete_command and
package_add_command will be executed to carry out the update.
package_verify_command’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Command to verify the correctness of an installed package
Example:
body package_method rpm
{
package_verify_command => "/bin/rpm -V";
}
Notes:
If available, this is a command to verify an already installed package. Such commands are not necessarily meaningful in the context of a tool like cfengine which patches the system by `other means'.
The promise is kept if the package is installed correctly, not kept otherwise.
Package managers generally expect the name of a package to be passed
as a parameter. However, in some cases we do not need to pass the name
of a particular package to the command. Ending the command string with
‘$’ prevents CFEngine from appending the package name to the
string.
package_version_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression with one backreference to extract package version string
Example:
body package_method rpm
{
package_version_regex => "[^\s]+ ([^.]+).*";
}
Notes:
If the version of a package is not specified separately using
package_version, then this should be a regular expression that
contains exactly one parenthesized back-reference that matches the version
string in the promiser. The regular expression may match a partial string
(that is, it is unanchored See Anchored vs. unanchored regular expressions).
package_multiline_start’Allowed input range: (arbitrary string)
Synopsis: Regular expression which matches the start of a new package in multiline output
Example:
body package_method solaris (pkgname, spoolfile, adminfile)
{
package_changes => "individual";
package_list_command => "/usr/bin/pkginfo -l";
package_multiline_start => "\s*PKGINST:\s+[^\s]+";
...
}
Notes:
This pattern is used in determining when a new package record begins. It is used when package managers (like the solaris package manager) use multi-line output formats. This pattern matches the first line of a new record.
package_policyType: (menu option)
Allowed input range:
adddeletereinstallupdateaddupdatepatchverify
Default value: verify
Synopsis: Criteria for package installation/upgrade on the current system
Example:
packages:
"$(match_package)"
package_policy => "add",
package_method => "xyz";
Notes:
This decides what fate is intended for the named package.
package_selectType: (menu option)
Allowed input range:
><==!=>=<=
Synopsis: A criterion for first acceptable match relative to "package_version"
Example:
packages:
"$(exact_package)"
package_policy => "add",
package_method => xyz,
package_select => ">=",
package_architectures => { "x86_64" },
package_version => "1.2.3-456";
Notes:
This selects the operator that compares the promiser to the state of the system packages currently installed. If the criterion matches, the policy action is scheduled for promise-keeping.
package_versionType: string
Allowed input range: (arbitrary string)
Synopsis: Version reference point for determining promised version
Example:
packages:
"mypackage"
package_policy => "add",
package_method => rpm,
package_select => "=",
package_version => "1.2.3";
Notes:
Used for specifying the targeted package version when the version is written separately from the name of the command.
processes promises in ‘agent’
Process promises refer to items in the system process table. Note that this is not the same as commands (which are instructions). A process is a command in some state of execution (with a Process Control Block). Promiser objects here are patterns that match line fragments in the system process table (that is, the patterns are unanchored See Anchored vs. unanchored regular expressions).
processes:
"regex contained in process line"
process_select => process_filter_body,
restart_class => "activation class for process",
..;
|
In cfengine 2 there was a restart clause for directly executing a
command to restart a process. In cfengine 3 there is instead
a class to activate. You must then desribe a command in that
class to restart the process.
commands: restart_me:: "/path/executable" ... ;This rationalizes complex restart-commands and avoids unnecessary overlap between
processes and commands.
The process_stop is also arguably a command, but it should be
an ephemeral command that does not lead to a persistent process. It is
intended only for commands of the form ‘/etc/inetd service stop’, not
for processes that persist. Processes are restarted at the end of a bundle's
execution, but stop commands are executed immediately.
Take care to note that process table formats differ between operating systems,
and the use of simple patterns such as program-names is recommended. For
more sophisticated matches, users should use the process_select
feature.
Note: process_select was previously called process filters in
cfengine 2 and earlier.
bundle agent example
{
processes:
".*"
process_count => anyprocs,
process_select => proc_finder;
reports:
any_procs::
"Found processes out of range";
}
########################################################
body process_select proc_finder
{
# Processes started between 5.5 hours and 20 minutes ago
stime_range => irange(ago(0,0,0,5,30,0),ago(0,0,0,0,20,0));
process_result => "stime";
}
########################################################
body process_count anyprocs
{
match_range => "0,0";
out_of_range_define => { "any_procs" };
}
In cfengine 2, one has two separate actions:
processes
shellcommands
In cfengine 3 we have
processes
commands
CFEngine 2 got this ontology about right intuitively, but not quite. It allowed a ‘restart’ command to appear in a process promise, which is really a command execution. This has been changed in cfengine 3 so that there is a cleaner separation. Let's see why.
Executions are about jobs, services, scripts etc. They are properties of an executable file. The referring `promiser' is a file object. On the other hand a process is a property of a "process identifier" which is a kernel instantiation, a quite different object altogether. So it makes sense to say that
kill signal pid
exec command argument1 argument2 ...
Neither the file nor the pid necessarily promise to respond to these activations, but they are nonetheless physically meaningful phenomena or attributes associated with these objects.
Executions lead to processes for the duration of their lifetime, so these two issues are related, although the promises themselves are not.
Services verus processes:
A service is an abstraction that requires processes to run and files to be configured. It makes a lot of sense to wrap services in modular bundles. Starting and stopping a service can be handled in at least two ways. Take the web service as an example.
We can start the service by promising an execution of a daemon (e.g. httpd).
Normally this execution does not terminate without intervention. We can
terminate it in one of two ways:
The first case makes sense if we need to qualify the termination by searching for the processes. The processes section of a cfengine 3 policy includes a control promise to search for matching processes. If matches are found, signals can be sent to precisely each specific process.
Classes can also be defined, in principle triggering an execution of the stop script, but then the class refers only to the presence of matching pids, not to the individual pids concerned. So it becomes the responsibility of the execution to locate and interact with the pids necessary.
Want it running?:
How do we say simply that we want a service running? In the agent control promises, we could check each service individually.
bundlesequence => { Update, Service("apache"), Service("nfsd") };
or
bundlesequence => { Update, @(globals.all_services) };
The bundle for this can look like this:
bundle agent Service("$(service)")
{
processes:
"$(service)"
process_count => up("$(service)");
commands:
"$daemons[$(service)]"
ifvarclass => "$(service)_up",
args => "$args[$(service)]";
}
An alternative would be self-contained:
bundle agent Service
{
vars:
"service" slist => { "apache", "nfsd", "bind" };
processes:
"$(service)"
process_count => up("$(service)");
commands:
"$daemons[$(service)]"
ifvarclass => "$(service)_up",
args => "$args[$(service)]";
}
######################
# Parameterized body
######################
body process_count("$(s)")
{
match_range => "[0,10]";
out_of_range_define => "$(s)_up";
}
Is this a step backwards? The cfengine 3 approach might seem like a step backwards from the simple cfengine 2 statement:
processes: "httpd" restart "/etc/init.d/apache restart"
However, it allows several improvements.
You can do other things in between stopping and starting the service, like file editing, or security sweeps. You can use templates to simplify the syntax in bulk for several process checks or restarts.
processes: "$(service.list)"If you don't want any delay in stopping and starting the service, then place these promises in a private bundle with nothing in between them.
process_count (compound body)Type: (ext body)
in_range_define’Allowed input range: (arbitrary string)
Synopsis: List of classes to define if the matches are in range
Example:
body process_count example
{
in_range_define => { "class1", "class2" };
}
Notes:
Classes are defined if the processes that are found in the process table satisfy the
promised process count, i.e. if the promise about the number of processes matching
the other criteria is kept.
match_range’Allowed input range: 0,99999999999
Synopsis: Integer range for acceptable number of matches for this process
Example:
body process_count example
{
match_range => irange("10","50");
}
Notes:
This is a numerical range for the number of occurrences of the
process in the process table. As long as it falls within the specified
limits, the promise is considered kept.
out_of_range_define’Allowed input range: (arbitrary string)
Synopsis: List of classes to define if the matches are out of range
Example:
body process_count example(s)
{
out_of_range_define => { "process_anomaly", "anomaly_$(s)"};
}
Notes:
Classes to activate remedial promises conditional on this promise failure to be kept.
process_select (compound body)Type: (ext body)
command’Allowed input range: (arbitrary string)
Synopsis: Regular expression matching the command/cmd field of a process
Example:
body process_select example
{
command => "cf-.*";
process_result => "command";
}
Notes:
This expression should match the entire COMMAND field of the
process table (not just a fragment). This field is usually the last
field on the line and thus starts with the first non-space character
and ends with the end of line.
pid’Allowed input range: 0,99999999999
Synopsis: Range of integers matching the process id of a process
Example:
body process_select example
{
pid => irange("1","10");
process_result => "pid";
}
Notes:
pgid’Allowed input range: 0,99999999999
Synopsis: Range of integers matching the parent group id of a process
Example:
body process_select example
{
pgid => irange("1","10");
process_result => "pgid";
}
Notes:
ppid’Allowed input range: 0,99999999999
Synopsis: Range of integers matching the parent process id of a process
Example:
body process_select example
{
ppid => irange("407","511");
process_result => "ppid";
}
Notes:
priority’Allowed input range: -20,+20
Synopsis: Range of integers matching the priority field (PRI/NI) of a process
Example:
body process_select example
{
priority => irange("-5","0");
}
Notes:
process_owner’Allowed input range: (arbitrary string)
Synopsis: List of regexes matching the user of a process
Example:
body process_select example
{
process_owner => { "wwwrun", "nobody" };
}
Notes:
Regular expression should match a legal user name on the system. The regex
must match the entire name (that is, it is anchored
See Anchored vs. unanchored regular expressions).
process_result’Allowed input range: [(process_owner|pid|ppid||pgid|rsize|vsize|status|command|ttime|stime|tty|priority|threads)[|&!.]*]*
Synopsis: Boolean class expression returning the logical combination of classes set by a process selection test
Example:
body process_select proc_finder(p)
{
process_owner => { "avahi", "bin" };
command => "$(p)";
pid => irange("100","199");
vsize => irange("0","1000");
process_result => "command.(process_owner|vsize).!pid";
}
Notes:
A logical combination of the process selection classifiers. The syntax
is the same as that for class expressions. There should be no spaces
in the expressions.
rsize’Allowed input range: 0,99999999999
Synopsis: Range of integers matching the resident memory size of a process, in kilobytes
Example:
body process_select
{
rsize => irange("4000","8000");
}
Notes:
status’Allowed input range: (arbitrary string)
Synopsis: Regular expression matching the status field of a process
Example:
body process_select example
{
status => "Z";
}
Notes:
For instance, characters in the set ‘NRS<sl+..’. Windows
processes do not have status fields.
stime_range’Allowed input range: 0,2147483647
Synopsis: Range of integers matching the start time of a process
Example:
body process_select example
{
stime_range => irange(ago(0,0,0,1,0,0),now);
}
Notes:
The calculation of time from process table entries is sensitive to
Daylight Savings Time (Summer/Winter Time) so calculations could be a
hour off. This is for now a bug to be fixed.
ttime_range’Allowed input range: 0,2147483647
Synopsis: Range of integers matching the total elapsed time of a process
Example:
body process_select example
{
ttime_range => irange(0,accumulated(0,1,0,0,0,0));
}
Notes:
This is total accumulated time for a process.
tty’Allowed input range: (arbitrary string)
Synopsis: Regular expression matching the tty field of a process
Example:
body process_select example
{
tty => "pts/[0-9]+";
}
Notes:
Windows processes are not regarded as attached to any terminal, so
they all have tty '?'.
threads’Allowed input range: 0,99999999999
Synopsis: Range of integers matching the threads (NLWP) field of a process
Example:
body process_select example
{
threads => irange(1,5);
}
Notes:
vsize’Allowed input range: 0,99999999999
Synopsis: Range of integers matching the virtual memory size of a process, in kilobytes
Example:
body process_select example
{
vsize => irange("4000","9000");
}
Notes:
On Windows, the virtual memory size is the amount of memory that cannot be shared with other processes. In Task Manager, this is called Commit Size (Windows 2008), or VM Size (Windows XP).
process_stopType: string
Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: A command used to stop a running process
Example:
processes:
"snmpd"
process_stop => "/etc/init.d/snmp stop";
Notes:
As an alternative to sending a termination or kill signal to a process, one may call a `stop script' to perform a graceful shutdown.
restart_classType: string
Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A class to be defined globally if the process is not running, so that a command: rule can be referred to restart the process
Example:
processes:
"cfservd"
restart_class => "start_cfserv";
commands:
start_cfserv::
"/usr/local/sbin/cfservd";
Notes:
This is a signal to restart a process that should be running, if it is not running. Processes are signalled first and then restarted later, at the end of bundle execution, after all possible corrective actions have been made that could influence their execution.
Windows does not support that processes start themselves in the background, like Unix daemons usually do (i.e. fork off a child process). Therefore, it may be useful to specify an action bodypart that sets background to true in a commands promise that is invoked by the class set by restart_class. See the commands promise type for more information.
signalsType: (option list)
Allowed input range:
hupinttrapkillpipecontabrtstopquittermchildusr1usr2bussegv
Synopsis: A list of menu options representing signals to be sent to a process
Example:
processes:
cfservd_out_of_control::
"cfservd"
signals => { "stop" , "term" },
restart_class => "start_cfserv";
any::
"snmpd"
signals => { "term" , "kill" };
Notes:
Signals are presented as an ordered list to the process. On windows, only the kill signal is supported, which terminates the process.
services promises in ‘agent’
A service is a set of zero or more processes. It can be zero if the
service is not currently running. Services run in the background, and
do not require user intervention.
Service promises may be viewed as an abstraction of process and commands promises. An important distinguiser is however that a single service may consist of multiple processes. Additionally, services are registered in the operating system in some way, and gets a unique name. Unlike processes and commands promises, this makes it possible to use the same name both when it is running and not.
Some operating systems are bundled with a lot of unused services that are running as default. At the same time, faulty or inherently insecure services are often the cause of security issues. With CFEngine Nova, one can create promises stating services that should be stopped and disabled.
The operating system may start a service at boot time, or it can be
started by CFEngine. Either way, CFEngine will ensure that the service
maintains the correct state (started, stopped, or disabled). On some
operating systems, CFEngine also allows services to be started on
demand, i.e. when they are needed. This is implemented though the
inetd or xinetd daemon on Unix. Windows does not support
this.
CFEngine Nova also allows for the concept of dependencies between services, and can automatically start or stop these, if desired. Parameters can be passed to services that are started by Cfengine.
bundle agent example
{
services:
"Dhcp"
service_policy => "start",
service_dependencies => { "Alerter", "W32Time" },
service_method => winmethod;
}
########################################################
body service_method winmethod
{
service_type => "windows";
service_args => "--netmask=255.255.0.0";
service_autostart_policy => "none";
service_dependence_chain => "start_parent_services";
}
Services promises are only avaiable in CFEngine Nova and above.
Windows Vista/Server 2008 and later introduced new complications to the service security policy. Therefore, when testing services promises from the command line, CFEngine may not be given proper access rights, which gives errors like "Access is denied". However, when running through the CFEngine Nova Executor service, which is done on production machines, CFEngine has sufficent rights.
service_policyType: (menu option)
Allowed input range:
startstopdisable
Synopsis: Policy for cfengine service status
Example:
services:
"Telnet"
service_policy => "disable";
Notes:
If set to start, CFEngine Nova will keep the service in a running state,
while stop means that the service is kept in a stopped state.
disable implies stop, and ensures that the service can not be
started directly, but needs to be enabled somehow first (e.g. by changing
file permissions).
service_dependenciesType: slist
Allowed input range: [a-zA-Z0-9_$()\[\].]+
Synopsis: A list of services on which the named service abstraction depends
Example:
services:
"ftp"
service_policy => "start",
service_dependencies => { "network", "logging" };
Notes:
A list of services that must be running before the service can be started.
These dependencies can be started automatically by CFEngine Nova if they
are not running — see service_dependence_chain. However, the
dependencies will never be implicitly stopped by CFEngine Nova. Specifying
dependencies is optional.
Note that the operating system may keep an additional list of dependencies
for a given service, defined during installation of the service. CFEngine
Nova requires these dependencies to be running as well before starting
the service. The complete list of dependencies is thus the union of
service_dependencies and the internal operating system list.
service_method (compound body)Type: (ext body)
service_type’Allowed input range:
windowsinitinetdxinetd
Synopsis: Service abstraction type
Example:
body service_method example
{
type => "windows";
}
Notes:
On Windows this defaults to, and must be windows.
Unix systems can however have multiple means of registering
services, but the choice must be available on the given system.
service_args’Allowed input range: (arbitrary string)
Synopsis: Parameters for starting the service
Example:
body service_method example
{
service_args => "-f filename.conf --some-argument";
}
Notes:
These arguments will only be passed if CFEngine Nova starts the
service. Thus, set service_autostart_policy to none
to ensure that the arguments are always passed.
Escaped quoutes can be used to pass an argument contianing spaces
as a single argument, e.g. "-f \"file name.conf\"". Passing arguments
is optional.
service_autostart_policy’Allowed input range:
noneboot_timeon_demand
Synopsis: Should the service be started automatically by the OS
Example:
body service_method example
{
service_autostart_policy => "boot_time";
}
Notes:
Defaults to none, which means that the service is not
registered for automatic startup by the operating system in any
way. It must be none if service_policy is not
start. boot_time means the service is started at boot
time, while on_demand means that the service is dispatched once
it is being used.
on_demand is not supported by Windows, and is implemented
through inetd or xinetd on Unix.
service_dependence_chain’Allowed input range:
ignorestart_parent_servicesstop_child_servicesall_related
Synopsis: How to handle dependencies and dependent services
Example:
body service_method example
{
service_dependence_chain => "start_parent_services";
}
Notes:
The service dependencies include both the dependencies defined by the
operating system and in service_dependencies, as described
there.
Defaults to ignore, which means that CFEngine Nova will never
start or stop dependencies or dependent services, but fail if
dependencies are not satisfied. start_parent_services means
that all dependencies of the service will be started if they are not
already running. When stopping a service, stop_child_services
means that other services that depend on this service will be stopped
also. all_related means both start_parent_services and
stop_child_services.
Note that this setting also affects dependencies of dependencies and so on.
For example, consider the case where service A depends on B, which
depends on C. If we want to start B, we must first make sure A is
running. If start_parent_services or all_related is set,
CFEngine Nova will start A, if it is not running. On the other hand,
if we want to stop B, C needs to be stopped
first. stop_child_services or all_related means that
CFEngine Nova will stop C, if it is running.
storage promises in ‘agent’
Storage promises refer to disks and filesystem properties.
storage:
"/disk volume or mountpoint"
volume => volume_body,
...;
|
In cfengine 2, storage promises were divided into disks or
required, and misc_mounts types. The old mount-models
for binary and home servers has been deprecated and removed from
cfengine 3. Users who use these models can reconstruct them from the
low-level tools.
bundle agent storage
{
storage:
"/usr" volume => mycheck("10%");
"/mnt" mount => nfs("nfsserv.example.org","/home");
}
#######################################################
body volume mycheck(free) # reusable template
{
check_foreign => "false";
freespace => "$(free)";
sensible_size => "10000";
sensible_count => "2";
}
body mount nfs(server,source)
{
mount_type => "nfs";
mount_source => "$(source)";
mount_server => "$(server)";
edit_fstab => "true";
}
mount (compound body)Type: (ext body)
edit_fstab’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false add or remove entries to the file system table ("fstab")
Default value: false
Example:
body mount example
{
edit_fstab => "true";
}
Notes:
The default behaviour is to not place edits in the file system table.
mount_type’Allowed input range:
nfsnfs2nfs3nfs4
Synopsis: Protocol type of remote file system
Example:
body mount example
{
mount_type => "nfs3";
}
Notes:
This field is mainly for future extensions.
mount_source’Allowed input range: "?(([a-zA-Z]:\\.*)|(/.*))
Synopsis: Path of remote file system to mount
Example:
body mount example
{
mount_source "/location/disk/directory";
}
Notes:
This is the location on the remote device, server, SAN etc.
mount_server’Allowed input range: (arbitrary string)
Synopsis: Hostname or IP or remote file system server
Example:
body mount example
{
mount_server => "nfs_host.example.org";
}
Notes:
Hostname or IP address, this could be on a SAN.
mount_options’Allowed input range: (arbitrary string)
Synopsis: List of option strings to add to the file system table ("fstab")
Example:
body mount example
{
mount_options => { "rw", "acls" };
}
Notes:
This list is concatenated in a form appropriate for the filesystem. The options must be
legal options for the system mount commands.
unmount’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false unmount a previously mounted filesystem
Default value: false
Example:
body mount example
{
unmount => "true";
}
Notes:
volume (compound body)Type: (ext body)
check_foreign’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false verify storage that is mounted from a foreign system on this host
Default value: false
Example:
body volume example
{
#..
check_foreign => "false";
}
Notes:
CFEngine will not normally perform sanity checks on filesystems which
are not local to the host. If true it will ignore a partition's
network location and ask the current host to verify storage located
physically on other systems.
freespace’Allowed input range: [0-9]+[MBkKgGmb%]
Synopsis: Absolute or percentage minimum disk space that should be available before warning
Example:
body volume example1
{
freespace => "10%";
}
body volume example2
{
freespace => "50M";
}
Notes:
The amount of freespace that is promised on a storage device. Once
this promise is found not to be kept, warnings are generated.
sensible_size’Allowed input range: 0,99999999999
Synopsis: Minimum size in bytes that should be used on a sensible-looking storage device
Example:
body volume example
{
sensible_size => "20K";
}
Notes:
body volume control
{
sensible_size => "20K";
}
sensible_count’Allowed input range: 0,99999999999
Synopsis: Minimum number of files that should be defined on a sensible-looking storage device
Example:
body volume example
{
sensible_count => "20";
}
Notes:
Files must be readable by the agent, i.e. it is assumed that the agent has privileges
on volumes being checked.
scan_arrivals’Allowed input range:
truefalseyesnoonoff
Synopsis: true/false generate pseudo-periodic disk change arrival distribution
Default value: false
Example:
body volume example
{
scan_arrivals => "true";
}
Notes:
This operation should not be left `on' for more than a single run (maximum once per week). It causes cfengine to perform an extensive disk scan noting the schedule of changes between files. This can be used for a number of analyses including optimum backup schedule computation.
server
bundle server access_rules()
{
access:
"/home/mark/PrivateFiles"
admit => { ".*\.example\.org" };
"/home/mark/\.cfagent/bin/cf-agent"
admit => { ".*\.example\.org" };
roles:
".*" authorize => { "mark" };
}
|
Bundles in the server describe access promises on specific file and class objects supplied by the server to clients.
access promises in ‘server’
Access promises are conditional promises made by the server about file
objects. The promise has two consequences. For file copy requests, the
file becomes transferrable to the remote client according to the
conditions specified in the server promse (i.e. if the connection
encryption requirements are met, and if the client has been granted
appropriate privileges with maproot (like its NFS counterpart)
to be able to see file objects not owned by the server process owner).
The promise has two mutally exclusive attributes ‘admit’ and ‘deny’. Use of ‘admit’ is preferred as mistakes and omissions can easily be made when excluding from a group.
When access is granted to a directory, the promise is automatically given about all of its contents and sub-directories. The access promise allows overlapping promises to be made, and these are kept in a first-come-first-served fashion. Thus file objects (promisers) should be listed in order of most-specific file first. In this way, specific promises will override less specific ones.
access:
"/path/file_object"
admit => { "hostname", "ipv4_address", "ipv6_address" };
|
#########################################################
# Server config
#########################################################
body server control
{
allowconnects => { "127.0.0.1" , "::1" };
allowallconnects => { "127.0.0.1" , "::1" };
trustkeysfrom => { "127.0.0.1" , "::1" };
}
#########################################################
bundle server access_rules()
{
access:
"/home/mark/LapTop"
admit => { "127.0.0.1" };
}
Entries may be literal addresses of IPv4 or IPv6, or any name registered
in the POSIX gethostbyname service.
admitType: slist
Allowed input range: (arbitrary string)
Synopsis: List of host names or IP addresses to grant access to file objects
Example:
access:
"/home/mark/LapTop"
admit => { "127.0.0.1", "192.168.0.1/24", ".*\.domain\.tld" };
Notes:
Admit promises grant access to file objects on the server. Arguments may be IP addresses or hostnames, provided DNS name resolution is active. In order to reach this stage, a client must first have passed all of the standard connection tests in the control body.
The lists may contain network addresses in CIDR notation or regular expressions to match the IP address or name of the connecting host.
denyType: slist
Allowed input range: (arbitrary string)
Synopsis: List of host names or IP addresses to deny access to file objects
Example:
bundle server access_rules()
{
access:
"/path"
admit => { ".*\.example\.org" },
deny => { "badhost_1\.example\.org", "badhost_1\.example\.org" };
}
Notes:
Denial is for special exceptions. A better strategy is always to grant on a need to know basis. A security policy based on exceptions is a weak one.
maprootType: slist
Allowed input range: (arbitrary string)
Synopsis: List of host names or IP addresses to grant full read-privilege on the server
Example:
access:
"/home"
admit => { "backup_host.example.org" },
ifencrypted => "true",
# Backup needs to have access to all users
maproot => { "backup_host.example.org" };
Notes:
Normally users authenticated by the server are granted access only to
files owned by them and no-one else.
Even if the cf-serverd process runs with root privileges on the
server side of a client-server connection, the client is not automatically
granted access to download files owned by non-privileged users. If maproot
is true then remote root users are granted access to all files.
A typical case where mapping is important is in making backups of many
user files. On the Windows cf-serverd, maproot is
required to read files if the connecting user does not own the file on
the server.
ifencryptedType: (menu option)
Allowed input range:
truefalseyesnoonoff
Default value: false
Synopsis: true/false whether the current file access promise is conditional on the connection from the client being encrypted
Example:
access:
"/path/file"
admit => { ".*\.example\.org" },
ifencrypted => "true";
Notes:
If this flag is true a client cannot access the file object unless its connection is encrypted.
resource_typeType: (menu option)
Allowed input range:
pathliteralcontextquery
Synopsis: The type of object being granted access (the default grants access to files)
Example:
bundle server access_rules()
{
vars:
"localvar" string => "literal string";
access:
"This is a $(localvar) for remote access"
handle => "test_scalar",
resource_type => "literal",
admit => { "127.0.0.1" };
}
Notes:
By default, access to resources granted by the server are
files. However, sometimes it is useful to cache literal
strings, hints and data in the server, e.g. the contents of variables,
hashed passwords etc for easy access. In the case of literal data, the
promise handle serves as the reference identifier for queries. Queries
are instigated by function calls by any agent.
The term query may also be used in commercial versions of
CFEngine to query the server for data from embedded databases. This is
currently for internal use only, and is used to grant access to report
`menus'.
roles promises in ‘server’
Roles promises are server-side decisions about which users are allowed
to define soft-classes on the server's system during remote invocation
of cf-agent. This implements a form of Role Based Access
Control (RBAC) for pre-assigned class-promise bindings. The user names
cited must be attached to trusted public keys in order to be accepted.
The regular expression must match the entire name (that is, they are
anchored See Anchored vs. unanchored regular expressions).
roles:
"regex"
authorize => { "usernames", ... };
|
It is worth re-iterating here that it is not possible to send
commands or modify promise definitions by remote access. At best users
may try to send classes when using cf-runagent in order to
activate sleeping promises. This mechanism limits their ability to
do this.
bundle server access_rules()
{
roles:
# Allow mark
"Mark_.*" authorize => { "mark" };
}
In this example user ‘mark’ is granted permission to remotely
activate classes matching the regular expression when using the
cf-runagent to activate cfengine. In this way one can
implement a form of Role Based Access Control (RBAC), provided
users do not have privileged access on the host directly.
authorizeType: slist
Allowed input range: (arbitrary string)
Synopsis: List of public-key user names that are allowed to activate the promised class during remote agent activation
Example:
roles:
".*" authorize => { "mark", "marks_friend" };
Notes:
Part of Role Based Access Control (RBAC) in cfengine. The users listed
in this section are granted access to set certain classes by using the
remote cf-runagent. The user-names will refer to public key
identities already trusted on the system.
knowledge
bundle knowledge system
{
topics:
Troubleshooting::
"Segmentation fault"
association => a("is caused by","Bad memory reference","can cause");
"Remote connection problem";
"Web server not running";
"Print server not running";
"Bad memory reference";
}
|
Knowledge bundles describe topic maps, i.e. Topics, Associations and Occurrences (of topics in documents). This is for knowledge modelling and has no functional effect on a system.
topics promises in ‘knowledge’
Topic promises are part of the knowledge management engine. A topic is
any string that refers to a concept or subject that we wish to include
in a knowledge base. If a topic has a very long name, it is best to made the
promiser object a short name and use the comment field
to add the long explanation (e.g. unique acronym and full text).
topics:
"topic string"
comment => "long name..",
...;
|
Topics form associative structures based entirely on an abstract space of natural language. Actually, this is only slightly more abstract than files, processes and commands etc. The main difference in knowledge management is that there are no corrective or maintenance operations associated with knowledge promises.
Class membership in knowledge management is subtly different from other parts of cfengine. If a topic lies in a certain class context, the topic uses it as a type-label. This is used for disambiguation of subject-area in searches rather than for disambiguation of rules between physical environments.
bundle knowledge example
{
topics:
"Distro"
comment => "Distribution of linux",
association => a("is a packaging of","Linux","is packaged as a");
}
Topics are basically identifiers, where the comment field here is a long form of the subject string. Associations form semantic links between topics. Topics can appear multiple times in order to form multiple associations.
association (compound body)Type: (ext body)
forward_relationship’Allowed input range: (arbitrary string)
Synopsis: Name of forward association between promiser topic and associates
Example:
body association example
{
forward_relation => "is bigger than";
}
Notes:
backward_relationship’Allowed input range: (arbitrary string)
Synopsis: Name of backward/inverse association from associates to promiser topic
Example:
body association example
{
# ..
backward_relationship => "is less than";
}
Notes:
Denotes the inverse name which is used to `moralizing' the association graph.
associates’Allowed input range: (arbitrary string)
Synopsis: List of associated topics by this forward relationship
Example:
body association example(literal,scalar,list)
{
#...
associates => { "literal", $(scalar), @(list)};
}
Notes:
An element of an association which is a list of topics to which the current topic is associated.
commentType: string
Allowed input range: (arbitrary string)
Synopsis: Retained comment about this promise's real intention
Example:
comment => "This comment follows the data for reference ...",
Notes:
Comments written in code follow the program, they are not merely discarded. They appear in reports and error messages.
occurrences promises in ‘knowledge’
Occurrences are documents or information resources that discuss topics. An occurrence promise asserts that a particular document of text resource in fact represents information about one or more topics. This is used to construct references to actual information in a topic map.
occurrences:
topic_name::
"URL reference or literal string"
represents => { "sub-topic disambiguator", ... },
representation => "literal or url";
|
Mark_Burgess::
"http://www.iu.hio.no/~mark"
represents => { "Home Page" };
lvalue::
"A variable identifier, i.e. the left hand side of an '=' association. The promiser in a variable promise."
represents => { "Definitions" },
representation => "literal";
Editing_Files::
"http://www.cfengine.org/confdir/customizepasswd.html"
represents => { "Setting up users" };
Occurrences are pointers to information about topics. This might be a literal text string or a URL reference to an external document.
representsType: slist
Allowed input range: (arbitrary string)
Synopsis: List of subtopics that explains the type(s) of information represented by the occurrence
Example:
occurrences:
Promise_Theory::
"A theory of autonomous actors that offer certainty through promises"
represents => { "Definitions" },
representation => "literal";
Notes:
The sub-topic or occurrence-type represented by the document reference in a knowledge base. This string is intended as an annotation to the reader about the nature of the inforation located in the occurrence document. It should be used `creatively'.
If the document type is an image and one of the items in this list is
a url, beginning with either ‘/’ or ‘http’, then
cf-know treats the reference as a url to be reached when the
image is clicked on.
representationType: (menu option)
Allowed input range:
literalurldbfilewebimageportal
Synopsis: How to interpret the promiser string e.g. actual data or reference to data
Example:
occurrences:
Promise_Theory::
"A theory of autonomous actors that offer certainty through promises"
represents => { "Definitions" },
representation => "literal";
Notes:
The form of knowledge representation in a topic map occurrence reference.
If the type portal is used it assumes that a new website should open in a new
target window.
web_rootType: string
Allowed input range: (arbitrary string)
Synopsis: Base URL of the occurrence when rendered as a web-URL (replaces path_root)
Example:
bundle knowledge demo
{
occurrences:
mytopic:
"reports/(.*)/mytopic_file.html"
represents => { "found in directory $(match.1)" },
representation => "file",
path_root => "$(enterprise_start.doc_root)",
web_root => "";
}
Notes:
When identifying occurrences by searching for files on the local file system, the web root provides the HTTP prefix for the document root under which we are searching so that path names can be mapped into URLs, See path_root in occurrences.
path_rootType: string
Allowed input range: (arbitrary string)
Synopsis: Base path of the occurrence when locating file (replaced by web_root)
Example:
bundle knowledge demo
{
occurrences:
mytopic:
"reports/(.*)/mytopic_file.html"
represents => { "found in directory $(match.1)" },
representation => "file",
path_root => "$(enterprise_start.doc_root)",
web_root => "";
}
Notes:
When searching a local file system for document occurrences, the path_root
points to the local file system's name for the document root. This will be
translated into the URL prefix defined by web_root, See web_root in occurrences.
inferences promises in ‘knowledge’
inferences:
"is close to"
comment => "Cluster property",
precedent => "is close to",
qualifier => "is close to";
"is far from"
comment => "Remote cluster property",
precedent => "is far from",
qualifier => "is close to";
History: Was introduced in version 3.1.0, Constellation 1.0.0 (2010)
The promiser is the result of the inference.
precedentType: string
Allowed input range: (arbitrary string)
Synopsis: The foundational vector for a trinary inference
Example:
inferences:
"is far from"
comment => "Remote cluster property",
precedent => "is far from",
qualifier => "is close to";
Notes:
History: Was introduced in version 3.1.0b3,Nova 2.0.0b1 (2010)
qualifierType: string
Allowed input range: (arbitrary string)
Synopsis: The second vector in a trinary inference
Example:
inferences:
"is far from"
comment => "Remote cluster property",
precedent => "is far from",
qualifier => "is close to";
Notes:
History: Was introduced in version 3.1.0, Constellation 1.0.0 (2010)
monitor
bundle monitor example
{
measurements:
# Discover disk device information
"/bin/df"
handle => "free_diskspace_watch",
stream_type => "pipe",
data_type => "slist",
history_type => "static",
units => "device",
match_value => file_systems;
}
|
Monitor bundles contain user defined promises for system discovery and monitoring.
measurements promises in ‘monitor’
These features are available only in Enterprise versions of cfengine.
Cfengine's monitoring component cf-monitord records a number
of performance data about the system by default. These include
process counts, service traffic, load average and cpu utilization and
temperature when available.
CFEngine Nova extends this in two ways. First it adds a three year trend summary based any `shift'-averages. Second, it adds customizable promises to monitor or log very specific user data through a generic interface. The end result is to either generate a periodic time series, like the above mentioned values, or to log the results to custom-defined reports.
CFEngine Nova adds a new promise type in bundles for the monitoring
agent. These are written just like all other promises within a bundle
destined for the agent concerned (however, you do not need to add them
to the bundlesequence – they are executed by cf-monitord
because they are bundles of type monitor). In this case:
bundle monitor watch
{
measurements:
# promises ...
}
It is important to specificy a promise handle for measurement
promises, as the names defined in the handle are used to determine the
name of the log file or variable to which data will be reported. Log
files are created under WORKDIR/state. Data that have no history
type are stored in a special variable context called ‘mon’, analogous
to the system variables in ‘sys’. Thus the values may be used
in other promises in the form $(mon.handle).
# Follow a special process over time
# using cfengine's process cache to avoid resampling
"/var/cfengine/state/cf_rootprocs"
handle => "monitor_self_watch",
stream_type => "file",
data_type => "int",
history_type => "weekly",
units => "kB",
match_value => proc_value(".*cf-monitord.*",
"root\s+[0-9.]+\s+[0-9.]+\s+[0-9.]+\s+[0-9.]+\s+([0-9]+).*");
# Discover disk device information
"/bin/df"
handle => "free_diskspace_watch",
stream_type => "pipe",
data_type => "slist",
history_type => "static",
units => "device",
match_value => file_systems;
# Update this as often as possible
}
##########################################################
body match_value proc_value(x,y)
{
select_line_matching => "$(x)";
extraction_regex => "$(y)";
}
body match_value file_systems
{
select_line_matching => "/.*";
extraction_regex => "(.*)";
}
Notes:
The general pattern of these promises is to decide the source of the information either file or pipe, determine the data type (integer, string etc.), specify a pattern to match the result in the file stream and then specify what to do with the result afterwards.
Standard measurements:
The cf-monitord service monitors a number of variables as
standard on Unix and Windows systems. Windows is fundamentally different
from Unix and currently has less support for out-of-the-box probes.
Slots with a higher number are used for custom measurement promises in CFEngine Nova.
These values collected and analysed by cf-monitord are
transformed into agent variables in the $(mon.name)
context.
Measurement promise syntax:
stream_typeType: (menu option)
Allowed input range:
pipefile
Synopsis: The datatype being collected.
Example:
stream_type => "pipe";
Notes:
CFEngine treats all input using a stream abstraction. The preferred interface is files, since they can be read without incurring the cost of a process. However pipes from executed commands may also be invoked.
data_typeType: (menu option)
Allowed input range:
counterintrealstringslist
Synopsis: The datatype being collected.
Example:
"/bin/df"
handle => "free_disk_watch",
stream_type => "pipe",
data_type => "slist",
history_type => "static",
units => "device",
match_value => file_systems,
action => sample_min(10,15);
Notes:
When cfengine (Nova) observes data, such as the attached partitions in
the example above, the datatype determines how that data will be
handled. Integer and real values, counters etc., are recorded as
time-series if the history type is `weekly', or as single values
otherwise. If multiple items are matched by an observation,
e.g. several lines in a file match the given regular expression,
then these can be made into a list by choosing slist, else
the first matching item will be selected.
history_typeType: (menu option)
Allowed input range:
weeklyscalarstaticlog
Synopsis: Whether the data can be seen as a time-series or just an isolated value
Example:
"/proc/meminfo"
handle => "free_memory_watch",
stream_type => "file",
data_type => "int",
history_type => "weekly",
units => "kB",
match_value => free_memory;
Notes:
unitsType: string
Allowed input range: (arbitrary string)
Synopsis: The engineering dimensions of this value or a note about its intent used in plots
Example:
"/var/cfengine/state/cf_rootprocs"
handle => "monitor_self_watch",
stream_type => "file",
data_type => "int",
history_type => "weekly",
units => "kB",
match_value => proc_value(".*cf-monitord.*",
"root\s+[0-9.]+\s+[0-9.]+\s+[0-9.]+\s+[0-9.]+\s+([0-9]+).*");
Notes:
This is an arbitary string used in documentation only.
match_value (compound body)Type: (ext body)
select_line_matching’Allowed input range: .*
Synopsis: Regular expression for matching line location
Example:
body match_value example
{
select_line_matching => "Expression match.* whole line";
}
Notes:
The expression must match a whole line, not a fragment within a line (that is, it is anchored See Anchored vs. unanchored regular expressions).
This attribute is mutually exclusive of select_line_number.
select_line_number’Allowed input range: 0,99999999999
Synopsis: Read from the n-th line of the output (fixed format)
Example:
body match_value find_line
{
select_line_number => "2";
}
Notes:
This is mutually exclusive of select_line_matching.
extraction_regex’Allowed input range: (arbitrary string)
Synopsis: Regular expression that should contain a single backreference for extracting a value
Example:
body match_value free_memory
{
select_line_matching => "MemFree:.*";
extraction_regex => "MemFree:\s+([0-9]+).*";
}
Notes:
A single parenthesized backreference should be given to lift the value to be measured out of the text stream.
The regular expression may match a partial string (that is, it is unanchored
See Anchored vs. unanchored regular expressions).
track_growing_file’Allowed input range:
truefalseyesnoonoff
Synopsis: If true, cfengine remembers the position to which is last read when opening the file, and resets to the start if the file has since been truncated
Example:
bundle monitor watch
{
measurements:
"/home/mark/tmp/file"
handle => "line_counter",
stream_type => "file",
data_type => "counter",
match_value => scan_log("MYLINE.*"),
history_type => "log",
action => sample_rate("0");
}
#
body match_value scan_log(x)
{
select_line_matching => "^$(x)$";
track_growing_file => "true";
}
#
body action sample_rate(x)
{
ifelapsed => "$(x)";
expireafter => "10";
}
Notes:
This option applies only to file based input streams. If this is ‘true’, CFEngine treats the file as if it were a log file, growing continuously. Thus the monitor reads all new entries since the last sampling time on each invocation. In this way, the monitor does not count lines in the log file redundantly.
This makes a log pattern promise equivalent to something like ‘tail -f logfile | grep pattern’ in Unix parlance.
There is a large number of functions built into CFEngine, and finding the
right one to use can be a daunting task. The following tables are designed
to make it easier for you to find the function you need, based on the value
or type that the function returns or processes as inputs.
| getindices | getusers | grep | ldaplist | peerleaders
|
| peers | readintlist | readreallist | readstringlist | splitstring
|
| accumulated | ago | countlinesmatching | diskfree | getfields
|
| getgid | getuid | now | on | randomint
|
| readintarray | readrealarray | readstringarray | readstringarrayidx | selectservers
|
| irange | rrange
|
| product | sum
|
| canonify | escape | execresult | getenv | hash
|
| host2ip | hostsseen | join | lastnode | ldapvalue
|
| peerleader | readfile | readtcp | registryvalue | remotescalar
|
| translatepath
|
The following functions all fill arrays, although they return values which depend on the number of items processed.
| getfields | readintarray | readrealarray | readstringarray | readstringarrayidx
|
| regextract
|
The following functions read data from inside CFEngine (from classes, lists, strings, etc.) and outside of CFEngine (from files, databases, arrays, etc.)
| getindices | regarray
|
| diskfree
|
| remoteclassesmatching | remotescalar
|
| classify | classmatch
|
| execresult | returnszero | usemodule
|
| getenv
|
| countlinesmatching | getfields | getusers | hashmatch | peerleader
|
| peerleaders | peers | readfile | readintarray | readintlist
|
| readrealarray | readreallist | readstringarray | readstringarrayidx | readstringlist
|
| regline
|
| ldaparray | ldaplist | ldapvalue | regldap
|
| readtcp | selectservers
|
| registryvalue
|
| grep | join
|
| product
| |
| reglist
| |
| sum
|
| hash | lastnode | regcmp | regextract | splitstring
|
| strcmp | translatepath
|
The following functions examine file metadata, but don't use the contents of the file.
| accessedbefore | changedbefore | fileexists | filesexist | isdir
|
| islink | isnewerthan | isplain
|
| isgreaterthan | islessthan | isvariable
|
The following functions all do date or time computation
| accessedbefore | accumulated | ago | changedbefore | isnewerthan
|
| now | on | splayclass
|
Synopsis: accessedbefore(arg0,arg1) returns type class
arg0 : Newer filename, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Older filename, in the range "?(([a-zA-Z]:\\.*)|(/.*))
True if arg1 was accessed before arg2 (atime)
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"do_it" and => { accessedbefore("/tmp/earlier","/tmp/later"), "linux" };
reports:
do_it::
"The secret changes have been accessed after the reference time";
}
Notes:
The function accesses the atime fields of a file and makes a comparison.
touch /tmp/reference
touch /tmp/secretfile
/usr/local/sbin/cf-agent -f ./unit_accessed_before.cf -K
R: The secret changes have been accessed after the reference time
Synopsis: accumulated(arg0,arg1,arg2,arg3,arg4,arg5) returns type int
arg0 : Years, in the range 0,1000
arg1 : Months, in the range 0,1000
arg2 : Days, in the range 0,1000
arg3 : Hours, in the range 0,1000
arg4 : Minutes, in the range 0,1000
arg5 : Seconds, in the range 0,40000
Convert an accumulated amount of time into a system representation
Example:
bundle agent testbundle
{
processes:
".*"
process_count => anyprocs,
process_select => proc_finder;
reports:
any_procs::
"Found processes in range";
}
########################################################
body process_select proc_finder
{
ttime_range => irange(accumulated(0,0,0,0,2,0),accumulated(0,0,0,0,20,0));
process_result => "ttime";
}
########################################################
body process_count anyprocs
{
match_range => "0,0";
out_of_range_define => { "any_procs" };
}
Notes:
In the example we look for processes that have accumulated between 2 and 20 minutes of total run time.
ARGUMENTS:
The accumulated function measures total accumulated runtime.
Arguments are applied additively, so that ago(0,0,2,27,90,0) means "2 days,
27 hours and 90 minutes of runtime" " – however, you are strongly encouraged
to keep your usage of accumulated sensible and readable, e.g.,
accumulated(0,0,0,48,0,0) or accumulated(0,0,0,0,90,0).
Synopsis: ago(arg0,arg1,arg2,arg3,arg4,arg5) returns type int
arg0 : Years, in the range 0,1000
arg1 : Months, in the range 0,1000
arg2 : Days, in the range 0,1000
arg3 : Hours, in the range 0,1000
arg4 : Minutes, in the range 0,1000
arg5 : Seconds, in the range 0,40000
Convert a time relative to now to an integer system representation
Example:
bundle agent testbundle
{
processes:
".*"
process_count => anyprocs,
process_select => proc_finder;
reports:
any_procs::
"Found processes out of range";
}
########################################################
body process_select proc_finder
{
# Processes started between 5.5 hours and 20 minutes ago
stime_range => irange(ago(0,0,0,5,30,0),ago(0,0,0,0,20,0));
process_result => "stime";
}
########################################################
body process_count anyprocs
{
match_range => "0,0";
out_of_range_define => { "any_procs" };
}
Notes:
The ago function measures time relative to now. Arguments are applied
in order, so that ago(0,18,55,27,0,0) means "18 months, 55 days, and 27 hours
ago" – however, you are strongly encouraged to keep your usage of ago
sensible and readable, e.g., ago(0,0,120,0,0,0) or ago(0,0,0,72,0,0).
ARGUMENTS:
Synopsis: canonify(arg0) returns type string
arg0 : String containing non-identifer characters, in the range .*
Convert an abitrary string into a legal class name
Example:
commands:
"/var/cfengine/bin/$(component)"
ifvarclass => canonify("start_$(component)");
Notes:
This is for use in turning arbitrary text into class data. See Function classify.
Synopsis: changedbefore(arg0,arg1) returns type class
arg0 : Newer filename, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Older filename, in the range "?(([a-zA-Z]:\\.*)|(/.*))
True if arg1 was changed before arg2 (ctime)
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"do_it" and => { changedbefore("/tmp/earlier","/tmp/later"), "linux" };
reports:
do_it::
"The derived file needs updating";
}
Notes:
Change times include both file permissions and file contents. Comparisons like this are normally used for updating files (like the `make' command).
Synopsis: classify(arg0) returns type class
arg0 : Input string, in the range .*
True if the canonicalization of the argument is a currently defined class
Example:
classes:
"i_am_the_policy_host" expression => classify("master.example.org");
Notes:
This function returns true if the canonical form of the argument is already a defined class. This is useful, for example, transforming variables into classes. See Function canonify.
Synopsis: classmatch(arg0) returns type class
arg0 : Regular expression, in the range .*
True if the regular expression matches any currently defined class
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"do_it" and => { classmatch(".*_cfengine_com"), "linux" };
reports:
do_it::
"Host matches pattern";
}
Notes:
The regular expression is matched against the current list of defined classes. The regular expression must match a complete class for the expression to be true, that is, the regex is anchored See Anchored vs. unanchored regular expressions.
Synopsis: countclassesmatching(arg0) returns type int
arg0 : Regular expression, in the range .*
Count the number of defined classes matching regex arg1
Example:
bundle agent example
{
vars:
"num" int => countclassesmatching("entropy.*low");
reports:
cfengine_3::
"Found $(num) classes matching";
}
Notes:
This function matches classes, using a regular expression that should match the whole line.
The function returns the number of classes matched.
Synopsis: countlinesmatching(arg0,arg1) returns type int
arg0 : Regular expression, in the range .*
arg1 : Filename, in the range "?(([a-zA-Z]:\\.*)|(/.*))
Count the number of lines matching regex arg1 in file arg2
Example:
bundle agent example
{
vars:
"no" int => countlinesmatching("m.*","/etc/passwd");
reports:
cfengine_3::
"Found $(no) lines matching";
}
Notes:
This function matches lines in the named file, using a regular expression that should match the whole line.
The function returns the number of lines matched.
Synopsis: diskfree(arg0) returns type int
arg0 : File system directory, in the range "?(([a-zA-Z]:\\.*)|(/.*))
Return the free space (in KB) available on the directory's current partition (0 if not found)
Example:
bundle agent example
{
vars:
"free" int => diskfree("/tmp");
reports:
cfengine_3::
"Freedisk $(free)";
}
Notes:
Values returned in kilobytes.
Synopsis: escape(arg0) returns type string
arg0 : IP address or string to escape, in the range .*
Escape regular expression characters in a string
Example:
bundle server control
{
allowconnects => { "127\.0\.0\.1", escape("192.168.2.1") };
}
Notes:
This function is useful for making inputs readable when a regular expression is required, but the literal string contains special characters. The function simply 'escapes' all the regular expression characters, so that you don't have to.
This in the example above, the string "192.168.2.1" is "escaped" to be equivalent to "192\.168\.2\.1" (because without the backslashes, the regular expression "192.168.2.1" will also match the IP ranges "192.168.201", "192.168.231", etc - since the dot character means "match any character" when used in a regular expression).
History: This function was introduced in CFEngine version 3.0.4 (2010)
Synopsis: execresult(arg0,arg1) returns type string
arg0 : Fully qualified command path, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Shell encapsulation option, in the range useshell,noshell
Execute named command and assign output to variable
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"my_result" string => execresult("/bin/ls /tmp","noshell");
reports:
linux::
"Variable is $(my_result)";
}
Notes:
The second argument (‘useshell’/‘noshell’) decides whether a shell will be used to encapsulate the command. This is necessary in order to combine commands with pipes etc, but remember that each command requires a new process that reads in files beyond cfengine's control. Thus using a shell is both a performance hog and a potential security issue.
Note: you should never use this function to execute comands that make
changes to the system. Such an operation is beyind cfengine's ability
to guarantee convergence, and on multiple passes and during syntax
verification, these function calls are executed resulting in system
changes that are `covert'. Calls to execresult should be for
discovery and information extraction only.
Note: if the command is not found, the result will be the empty string!
Change: policy change in CFEngine 3.0.5. Previously newlines were changed for spaces, now newlines are preserved.
Synopsis: fileexists(arg0) returns type class
arg0 : File object name, in the range "?(([a-zA-Z]:\\.*)|(/.*))
True if the named file can be accessed
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"exists" expression => fileexists("/etc/passwd");
reports:
exists::
"File exists";
}
Notes:
The user must have access permissions to the file for this to work faithfully.
Synopsis: filesexist(arg0) returns type class
arg0 : Array identifier containing list, in the range @[(][a-zA-Z0-9]+[)]
True if the named list of files can ALL be accessed
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"mylist" slist => { "/tmp/a", "/tmp/b", "/tmp/c" };
classes:
"exists" expression => filesexist("@(mylist)");
reports:
exists::
"Files exist";
!exists::
"Do not exist";
}
Notes:
The user must have access permissions to the file for this to work faithfully.
Synopsis: getenv(arg0,arg1) returns type string
arg0 : Name of environment variable, in the range [a-zA-Z0-9_$()\[\].]+
arg1 : Maximum number of characters to read , in the range 0,99999999999
Return the environment variable named arg1, truncated at arg2 characters
Example:
bundle agent example
{
vars:
"myvar" string => getenv("PATH","20");
classes:
"isdefined" not => strcmp("$(myvar)","");
reports:
isdefined::
"The path is $(myvar)";
!isdefined::
"The named variable PATH does not exist";
}
Notes:
Returns an empty string if the environment variable is not defined. Arg2 is used to avoid unexpectedly large return values, which could lead to security issues. Choose a reasonable value based on the environment variable you are querying.
History: This function was introduced in CFEngine version 3.0.4 (2010)
Synopsis: getfields(arg0,arg1,arg2,arg3) returns type int
arg0 : Regular expression to match line, in the range .*
arg1 : Filename to read, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg2 : Regular expression to split fields, in the range .*
arg3 : Return array name, in the range .*
Get an array of fields in the lines matching regex arg1 in file arg2, split on regex arg3 as array name arg4
Example:
bundle agent example
{
vars:
"no" int => getfields("mark:.*","/etc/passwd",":","userdata");
reports:
cfengine_3::
"Found $(no) lines matching";
"Mark's homedir = $(userdata[6])";
}
Notes:
This function matches lines (using a regular expression) in the named file, and
splits the first matched line into fields (using a second) regular expression),
placing these into a named array whose elements are array[1],array[2],...
This is useful for examining user data in the Unix password or group files.
The function returns the number of lines matched. This function is most useful when you want only the first matching line (e.g., to mimic the behavior of the getpwnam(3) on the file /etc/passwd). If you want to examine all matching lines, See Function readstringarray instead.
Synopsis: getgid(arg0) returns type int
arg0 : Group name in text, in the range .*
Return the integer group id of the named group on this host
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"gid" int => getgid("users");
reports:
Yr2008::
"Users gid is $(gid)";
}
Notes:
If the named group does not exist, the variable will not be defined. On windows, which does not support group ids, the variable will not be defined.
Synopsis: getindices(arg0) returns type slist
arg0 : CFEngine array identifier, in the range [a-zA-Z0-9_$()\[\].]+
Get a list of keys to the array whose id is the argument and assign to variable
Example:
body common control
{
any::
bundlesequence => { "testsetvar" };
}
#######################################################
bundle agent testsetvar
{
vars:
"v[index_1]" string => "value_1";
"v[index_2]" string => "value_2";
"parameter_name" slist => getindices("v");
reports:
Yr2008::
"Found index: $(parameter_name)";
}
Notes:
Make sure you specify the correct scope when supplying the name of the variable.
Synopsis: getuid(arg0) returns type int
arg0 : User name in text, in the range .*
Return the integer user id of the named user on this host
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"uid" int => getuid("mark");
reports:
Yr2008::
"Users uid is $(uid)";
}
Notes:
If the named user is not registered the variable will not be defined. On windows, which does not support user ids, the variable will not be defined.
Synopsis: getusers(arg0,arg1) returns type slist
arg0 : Comma separated list of User names, in the range .*
arg1 : Comma separated list of UserID numbers, in the range .*
Get a list of all system users defined, minus those names defined in args 1 and uids in args
Example:
vars:
"allusers" slist => getusers("zenoss,mysql,at","12,0");
reports:
linux::
"Found user $(allusers)";
Notes:
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010) This function is only available on Unix-like systems in the present version.
The function has two arguments, both are comma separated lists. The first argument is a list of user names that should be excluded from the output. The second is a list of integrer UIDs that should be excluded.
Synopsis: grep(arg0,arg1) returns type slist
arg0 : Regular expression, in the range .*
arg1 : CFEngine array identifier, in the range [a-zA-Z0-9_$()\[\].]+
Extract the sub-list if items matching the regular expression in arg1 of the list named in arg2
Example:
bundle agent test
{
vars:
"mylist" slist => { "One", "Two", "Three", "Four", "Five" };
"sublist" slist => grep("T.*","mylist");
reports:
linux::
"Item: $(sublist)";
}
Notes:
Extracts a sublist of a list variable matching the regular expression in arg 1.
Synopsis: groupexists(arg0) returns type class
arg0 : Group name or identifier, in the range .*
True if group or numerical id exists on this host
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"gname" expression => groupexists("users");
"gid" expression => groupexists("100");
reports:
gname::
"Group exists by name";
gid::
"Group exists by id";
}
Notes:
The group may be specified by name or number.
Synopsis: hash(arg0,arg1) returns type string
arg0 : Input text, in the range .*
arg1 : Hash or digest algorithm, in the range md5,sha1,sha256,sha512,sha384,crypt
Return the hash of arg1, type arg2 and assign to a variable
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"md5" string => hash("CFEngine is not cryptic","md5");
reports:
Yr2008::
"Hashed to: $(md5)";
}
Notes:
Hash functions are extremely sensitive to input. You should not expect to get the same answer from this function as you would from every other tool, since it depends on how whitespace and end of file characters are handled.
Valid hash types (depending on availablity) include:
md5, sha1, sha256, sha512 ,sha384,
crypt.
Synopsis: hashmatch(arg0,arg1,arg2) returns type class
arg0 : Filename to hash, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Hash or digest algorithm, in the range md5,sha1,crypt,cf_sha224,cf_sha256,cf_sha384,cf_sha512
arg2 : ASCII representation of hash for comparison, in the range [a-zA-Z0-9_$()\[\].]+
Compute the hash of arg1, of type arg2 and test if it matches the value in arg 3
Example:
bundle agent example
{
classes:
"matches" expression => hashmatch("/etc/passwd","md5","c5068b7c2b1707f8939b283a2758a691");
reports:
matches::
"File has correct version";
}
Notes:
(class) hashmatch(file,md5|sha1|crypt,hash-comparison);
|
This function may be used to determine whether a system has a particular version of a binary file (e.g. software patch).
ARGUMENTS:
Synopsis: host2ip(arg0) returns type string
arg0 : Host name in ascii, in the range .*
Returns the primary name-service IP address for the named host
Example:
bundle server control
{
allowconnects => { escape(host2ip("www.example.com")) };
}
Notes:
Uses whatever configured name service is used by the resolver library to translate a hostname into an IP address. It will return an IPv6 address by preference if such an address exists. This function uses the standard lookup procedure for a name, so it mimics internal processes and can therefore be used not only to cache multiple lookups in the configuration, but to debug the behaviour of the resolver.
History: This function was introduced in CFEngine version 3.0.4 (2010)
Synopsis: hostinnetgroup(arg0) returns type class
arg0 : Host name, in the range .*
True if the current host is in the named netgroup
Example:
classes:
"ingroup" expression => hostinnetgroup("my_net_group");
Notes:
Synopsis: hostrange(arg0,arg1) returns type class
arg0 : Hostname prefix, in the range .*
arg1 : Enumerated range, in the range .*
True if the current host lies in the range of enumerated hostnames specified
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"compute_nodes" expression => hostrange("cpu-","01-32");
reports:
compute_nodes::
"No computer is a cluster";
}
Notes:
This is a pattern matching function for non-regular (enumerated) expressions.
Synopsis: hostsseen(arg0,arg1,arg2) returns type string
arg0 : Horizon since last seen in hours, in the range 0,99999999999
arg1 : Complements for selection policy, in the range lastseen,notseen
arg2 : Type of return value desired, in the range name,address
Extract the list of hosts last seen/not seen within the last arg1 hours
Example:
bundle agent test
{
vars:
"myhosts" slist => { hostsseen("inf","lastseen","address") };
reports:
cfengine_3::
"Found client/peer: $(myhosts)";
}
Notes:
Finds a list of hosts seen by a cfengine remote connection on the current host within the number of hours specified by argument 1. Argument 2 may be ‘lastseen’ or ‘notseen’, the latter being all hosts not observed to have connected within the specified time. Argument 3 may be ‘address’ or ‘name’, to return ip address or hostname form.
Synopsis: hubknowledge(arg0) returns type string
arg0 : Variable identifier, in the range [a-zA-Z0-9_$()\[\].]+
Read global knowledge from the hub host by id (commercial extension)
Example:
vars:
"global_number" string => hubknowledge("number_variable");
Notes:
This function is only available in commercial releases of CFEngine. It is intended for use in distributed orchestration. It is recommended that you use this function sparingly with guards, as it contributes to network traffic and depends on the network for its function.
This function behaves is essentially similar to the
remotescalar function, except that it always gets its
information from the policy server hub by an encrypted connection. It
is designed for spreading globally calibrated information about a
CFEngine swarm back to the client machines. The data available through
this channel are generated automatically by discovery, unlike
remotescalar which accesses user defined data.
Synopsis: iprange(arg0) returns type class
arg0 : IP address range syntax, in the range .*
True if the current host lies in the range of IP addresses specified
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"adhoc_group_1" expression => iprange("128.39.89.10-15");
"adhoc_group_2" expression => iprange("128.39.74.1/23");
reports:
adhoc_group_1::
"Some numerology";
adhoc_group_2::
"The masked warriors";
}
Notes:
Pattern matching based on IP addresses.
Synopsis: irange(arg0,arg1) returns type irange [int,int]
arg0 : Integer, in the range -99999999999,9999999999
arg1 : Integer, in the range -99999999999,9999999999
Define a range of integer values for cfengine internal use
Example:
irange("1","100");
irange(ago(0,0,0,1,30,0), "0");
Notes:
Used for any scalar attribute which requires an integer range. You can generally interchangeably say ‘"1,10"’ or ‘irange("1","10")’ (however, if you want to create a range of dates or times, you must use irange if you also use the functions ‘ago’, ‘now’, ‘accumulated’, etc).
Synopsis: isdir(arg0) returns type class
arg0 : File object name, in the range "?(([a-zA-Z]:\\.*)|(/.*))
True if the named object is a directory
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"isdir" expression => isdir("/etc");
reports:
isdir::
"Directory exists..";
}
Notes:
The cfengine process must have access to the object concerned in order for this to work.
Synopsis: isexecutable(arg0) returns type class
arg0 : File object name, in the range "?(([a-zA-Z]:\\.*)|(/.*))
True if the named object has execution rights for the current user
Example:
classes:
"yes" expression => isexecutable("/bin/ls");
Notes:
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
Synopsis: isgreaterthan(arg0,arg1) returns type class
arg0 : Larger string or value, in the range .*
arg1 : Smaller string or value, in the range .*
True if arg1 is numerically greater than arg2, else compare strings like strcmp
Example:
body common control
{
bundlesequence => { "test" };
}
###########################################################
bundle agent test
{
classes:
"ok" expression => isgreaterthan("1","0");
reports:
ok::
"Assertion is true";
!ok::
"Assertion is false";
}
Notes:
The comparison is made numerically if possible. If the values are strings, the result is identical to that of comparing with ‘strcmp()’.
Synopsis: islessthan(arg0,arg1) returns type class
arg0 : Smaller string or value, in the range .*
arg1 : Larger string or value, in the range .*
True if arg1 is numerically less than arg2, else compare strings like NOT strcmp
Example:
body common control
{
bundlesequence => { "test" };
}
###########################################################
bundle agent test
{
classes:
"ok" expression => islessthan("0","1");
reports:
ok::
"Assertion is true";
!ok::
"Assertion is false";
}
Notes:
The complement of isgreaterthan.
The comparison is made numerically if possible. If the values are
strings, the result is identical to that of comparing with ‘strcmp()’.
Synopsis: islink(arg0) returns type class
arg0 : File object name, in the range "?(([a-zA-Z]:\\.*)|(/.*))
True if the named object is a symbolic link
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"isdir" expression => islink("/tmp/link");
reports:
isdir::
"Directory exists..";
}
Notes:
The link node must both exist and be a symbolic link. Hard links cannot be detected using this function. A hard link is a regular file or directory.
Synopsis: isnewerthan(arg0,arg1) returns type class
arg0 : Newer file name, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Older file name, in the range "?(([a-zA-Z]:\\.*)|(/.*))
True if arg1 is newer (modified later) than arg2 (mtime)
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"do_it" and => { isnewerthan("/tmp/later","/tmp/earlier"), "linux" };
reports:
do_it::
"The derived file needs updating";
}
Notes:
This function compares the modification time of the file, referring to changes of content only.
Synopsis: isplain(arg0) returns type class
arg0 : File object name, in the range "?(([a-zA-Z]:\\.*)|(/.*))
True if the named object is a plain/regular file
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"isplain" expression => isplain("/etc/passwd");
reports:
isplain::
"File exists..";
}
Notes:
Synopsis: isvariable(arg0) returns type class
arg0 : Variable identifier, in the range [a-zA-Z0-9_$()\[\].]+
True if the named variable is defined
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"bla" string => "xyz..";
classes:
"exists" expression => isvariable("bla");
reports:
exists::
"Variable exists: \"$(bla)\"..";
}
Notes:
The variable need only exist. This says nothing about its value. Use regcmp
to check variable values.
Synopsis: join(arg0,arg1) returns type string
arg0 : Join glue-string, in the range .*
arg1 : CFEngine array identifier, in the range [a-zA-Z0-9_$()\[\].]+
Join the items of arg2 into a string, using the conjunction in arg1
Example:
bundle agent test
{
vars:
"mylist" slist => { "one", "two", "three", "four", "five" };
"scalar" string => join("<->","mylist");
reports:
linux::
"Concatenated $(scalar)";
}
Notes:
Converts a string of type list into a scalar variable using the join string in first argument.
Synopsis: lastnode(arg0,arg1) returns type string
arg0 : Input string, in the range .*
arg1 : Link separator, e.g. /,:, in the range .*
Extract the last of a separated string, e.g. filename from a path
Example:
bundle agent yes
{
vars:
"path1" string => "/one/two/last1";
"path2" string => "one:two:last2";
"last1" string => lastnode("$(path1)","/");
"last2" string => lastnode("$(path2)",":");
"last3" string => lastnode("$(path2)","/");
reports:
Yr2009::
"Last = $(last1),$(last2),$(last3)";
}
Notes:
This function returns the final node in a chain, given a regular expression to split on. This is mainly useful for finding leaf-names of files, from a fully qualified path name.
Synopsis: laterthan(arg0,arg1,arg2,arg3,arg4,arg5) returns type class
arg0 : Years, in the range 0,1000
arg1 : Months, in the range 0,1000
arg2 : Days, in the range 0,1000
arg3 : Hours, in the range 0,1000
arg4 : Minutes, in the range 0,1000
arg5 : Seconds, in the range 0,40000
True if the current time is later than the given date
Example:
classes: "after_deadline" expression => laterthan(2000,1,1,0,0,0);
Notes:
The arguments are standard time, See Function on.
Synopsis: ldaparray(arg0,arg1,arg2,arg3,arg4,arg5) returns type class
arg0 : URI, in the range .*
arg1 : Distinguished name, in the range .*
arg2 : Filter, in the range .*
arg3 : Record name, in the range .*
arg4 : Search scope policy, in the range subtree,onelevel,base
arg5 : Security level, in the range none,ssl,sasl
Extract all values from an ldap record
Example:
classes:
"gotdata" expression => ldaparray(
"myarray",
"ldap://ldap.example.org",
"dc=cfengine,dc=com",
"(uid=mark)",
"subtree",
"none");
Notes:
(class) ldaparray (array,uri,dn,filter,scope,security)
|
This function retrieves an entire record with all elements and populates an associative array with the entries. It returns a class which is true if there was a match for the search and false if nothing was retrieved.
ARGUMENTS:
"ldap://ldap.cfengine.com.no"
subtree
onelevel
base
none
ssl
sasl
Synopsis: ldaplist(arg0,arg1,arg2,arg3,arg4,arg5) returns type slist
arg0 : URI, in the range .*
arg1 : Distinguished name, in the range .*
arg2 : Filter, in the range .*
arg3 : Record name, in the range .*
arg4 : Search scope policy, in the range subtree,onelevel,base
arg5 : Security level, in the range none,ssl,sasl
Extract all named values from multiple ldap records
Example:
vars:
# Get all matching values for "uid" - should be a single record match
"list" slist => ldaplist(
"ldap://ldap.example.org",
"dc=cfengine,dc=com",
"(sn=User)",
"uid",
"subtree",
"none"
);
Notes:
(slist) ldaplist(uri,dn,filter,name,scope,security)
|
This function retrieves a single field from all matching LDAP records identified by the search parameters.
ARGUMENTS:
"ldap://ldap.cfengine.com.no"
uid.
subtree
onelevel
base
none
ssl
sasl
Synopsis: ldapvalue(arg0,arg1,arg2,arg3,arg4,arg5) returns type string
arg0 : URI, in the range .*
arg1 : Distinguished name, in the range .*
arg2 : Filter, in the range .*
arg3 : Record name, in the range .*
arg4 : Search scope policy, in the range subtree,onelevel,base
arg5 : Security level, in the range none,ssl,sasl
Extract the first matching named value from ldap
Example:
vars:
# Get the first matching value for "uid" in schema
"value" string => ldapvalue(
"ldap://ldap.example.org",
"dc=cfengine,dc=com",
"(sn=User)",
"uid",
"subtree",
"none"
);
Notes:
(string) ldapvalue(uri,dn,filter,name,scope,security)
|
This function retrieves a single field from a single LDAP record identified by the search parameters. The first matching value it taken.
ARGUMENTS:
"ldap://ldap.cfengine.com.no"
uid.
subtree
onelevel
base
Synopsis: now() returns type int
Convert the current time into system representation
Example:
body file_select zero_age
{
mtime => irange(ago(1,0,0,0,0,0),now);
file_result => "mtime";
}
Notes:
Synopsis: on(arg0,arg1,arg2,arg3,arg4,arg5) returns type int
arg0 : Year, in the range 1970,3000
arg1 : Month, in the range 1,12
arg2 : Day, in the range 1,31
arg3 : Hour, in the range 0,23
arg4 : Minute, in the range 0,59
arg5 : Second, in the range 0,59
Convert an exact date/time to an integer system representation
Example:
body file_select zero_age
{
mtime => irange(on(2000,1,1,0,0,0),now);
file_result => "mtime";
}
Notes:
An absolute date in the local timezone. Note that in process matching dates could be wrong by an hour depending on Daylight Savings Time / Summer Time. This is a known bug to be fixed.
ARGUMENTS:
Synopsis: peers(arg0,arg1,arg2) returns type slist
arg0 : File name of host list, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Comment regex pattern, in the range .*
arg2 : Peer group size, in the range 0,99999999999
Get a list of peers (not including ourself) from the partition to which we belong
Example:
bundle agent peers
{
vars:
"mygroup" slist => peers("/tmp/hostlist","#.*",4);
"myleader" string => peerleader("/tmp/hostlist","#.*",4);
"all_leaders" slist => peerleaders("/tmp/hostlist","#.*",4);
reports:
linux::
"mypeer $(mygroup)";
"myleader $(myleader)";
"another leader $(all_leaders)";
}
Notes:
(slist) peers(file of hosts,comment pattern,group size);
|
This function returns a list of hostnames that may be considered peers of the current host. Peers are defined according to a list of hosts, provided as a file in the first argument. This file should contain a list (one per line), possible with comments, of fully qualified host names. CFEngine breaks up this list into non-overlapping groups of up to groupsize, each of which has a leader which is the first host in the group.
The current host should belong to this file if it is expected to interact with the others. The function returns nothing if the host does not belong to the list.
ARGUMENTS:
Example file:
one
two
three # this is a comment
four
five
six
seven
eight
nine
ten
eleven
twelve
etc
Synopsis: peerleader(arg0,arg1,arg2) returns type string
arg0 : File name of host list, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Comment regex pattern, in the range .*
arg2 : Peer group size, in the range 0,99999999999
Get the assigned peer-leader of the partition to which we belong
Example:
bundle agent peers
{
vars:
"mygroup" slist => peers("/tmp/hostlist","#.*",4);
"myleader" string => peerleader("/tmp/hostlist","#.*",4);
"all_leaders" slist => peerleaders("/tmp/hostlist","#.*",4);
reports:
linux::
"mypeer $(mygroup)";
"myleader $(myleader)";
"another leader $(all_leaders)";
}
Notes:
(string) peerleader(file of hosts,comment pattern,group size);
|
This function returns the name of a ost that may be considered the leader of a group of peers of the current host. Peers are defined according to a list of hosts, provided as a file in the first argument. This file should contain a list (one per line), possibly with comments, of fully qualified host names. CFEngine breaks up this list into non-overlapping groups of up to groupsize, each of which has a leader which is the first host in the group.
The current host should belong to this file if it is expected to interact with the others. The function returns nothing if the host does not belong to the list.
ARGUMENTS:
Example file:
one
two
three # this is a comment
four
five
six
seven
eight
nine
ten
eleven
twelve
etc
Synopsis: peerleaders(arg0,arg1,arg2) returns type slist
arg0 : File name of host list, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Comment regex pattern, in the range .*
arg2 : Peer group size, in the range 0,99999999999
Get a list of peer leaders from the named partitioning
Example:
bundle agent peers
{
vars:
"mygroup" slist => peers("/tmp/hostlist","#.*",4);
"myleader" string => peerleader("/tmp/hostlist","#.*",4);
"all_leaders" slist => peerleaders("/tmp/hostlist","#.*",4);
reports:
linux::
"mypeer $(mygroup)";
"myleader $(myleader)";
"another leader $(all_leaders)";
}
Notes:
(slist) peers(file of hosts,comment pattern,group size);
|
This function returns a list of hostnames that may be considered peer leaders in the partitioning scheme described in the file of hosts. Peers are defined according to a list of hosts, provided as a file in the first argument. This file should contain a list (one per line), possible with comments, of fully qualified host names. CFEngine breaks up this list into non-overlapping groups of up to groupsize, each of which has a leader which is the first host in the group.
The current host need not belong to this file.
ARGUMENTS:
Example file:
one
two
three # this is a comment
four
five
six
seven
eight
nine
ten
eleven
twelve
etc
Synopsis: product(arg0) returns type real
arg0 : A list of arbitrary real values, in the range [a-zA-Z0-9_$()\[\].]+
Return the product of a list of reals
Example:
bundle agent test
{
vars:
"series" rlist => { "1.1", "2.2", "3.3", "5.5", "7.7" };
"prod" real => product("series");
"sum" real => sum("series");
reports:
cfengine_3::
"Product result: $(prod) > $(sum)";
}
Notes:
Of course, you could easily combine product with readstringarray
or readreallist, etc. to collect summary information from a source
external to CFEngine.
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
This function might be used for simple ring computation.
Synopsis: randomint(arg0,arg1) returns type int
arg0 : Lower inclusive bound, in the range -99999999999,9999999999
arg1 : Upper inclusive bound, in the range -99999999999,9999999999
Generate a random integer between the given limits
Example:
vars: "ran" int => randomint(4,88);
Notes:
The limits must be integer values and the resulting numbers are based on the entropy of the md5 algorithm.
Synopsis: readfile(arg0,arg1) returns type string
arg0 : File name, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Maximum number of bytes to read, in the range 0,99999999999
Read max number of bytes from named file and assign to variable
Example:
vars:
"xxx"
string => readfile( "/home/mark/tmp/testfile" , "33" );
Notes:
The file (fragment) is read into a single scalar variable.
Synopsis: readintarray(arg0,arg1,arg2,arg3,arg4,arg5) returns type int
arg0 : Array identifer to populate, in the range [a-zA-Z0-9_$()\[\].]+
arg1 : File name to read, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg2 : Regex matching comments, in the range .*
arg3 : Regex to split data, in the range .*
arg4 : Maximum number of entries to read, in the range 0,99999999999
arg5 : Maximum bytes to read, in the range 0,99999999999
Read an array of integers from a file and assign the dimension to a variable
Example:
vars:
"dim_array"
int => readintarray("array_name","/tmp/array","#[^\n]*",":",10,4000);
ARGUMENTS:
comment field will strip out unwanted patterns from the file being
read, leaving unstripped characters to be split into fields. The
regex is unanchored See Anchored vs. unanchored regular expressions.
split regex is also unanchored.
Notes:
Reads a two dimensional array from a file. One dimension is separated by the character specified in the argument, the other by the the lines in the file. The first field of the lines names the first array argument.
1: 5:7:21:13
2:19:8:14:14
3:45:1:78:22
4:64:2:98:99
Results in
array_name[1][0] 1
array_name[1][1] 5
array_name[1][2] 7
array_name[1][3] 21
array_name[1][4] 13
array_name[2][0] 2
array_name[2][1] 19
array_name[2][2] 8
array_name[2][3] 14
array_name[2][4] 14
array_name[3][0] 3
array_name[3][1] 45
array_name[3][2] 1
array_name[3][3] 78
array_name[3][4] 22
array_name[4][0] 4
array_name[4][1] 64
array_name[4][2] 2
array_name[4][3] 98
array_name[4][4] 99
Synopsis: readintlist(arg0,arg1,arg2,arg3,arg4) returns type ilist
arg0 : File name to read, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Regex matching comments, in the range .*
arg2 : Regex to split data, in the range .*
arg3 : Maximum number of entries to read, in the range 0,99999999999
arg4 : Maximum bytes to read, in the range 0,99999999999
Read and assign a list variable from a file of separated ints
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"mylist" ilist => { readintlist("/tmp/listofint","#.*","[\n]",10,400) };
reports:
Yr2008::
"List entry: $(mylist)";
}
ARGUMENTS:
comment field will strip out unwanted patterns from the file being
read, leaving unstripped characters to be split into fields. The
regex is unanchored See Anchored vs. unanchored regular expressions.
split regex is also unanchored.
Notes:
Synopsis: readrealarray(arg0,arg1,arg2,arg3,arg4,arg5) returns type int
arg0 : Array identifer to populate, in the range [a-zA-Z0-9_$()\[\].]+
arg1 : File name to read, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg2 : Regex matching comments, in the range .*
arg3 : Regex to split data, in the range .*
arg4 : Maximum number of entries to read, in the range 0,99999999999
arg5 : Maximum bytes to read, in the range 0,99999999999
Read an array of real numbers from a file and assign the dimension to a variable
Example:
vars:
"dim_array"
int => readrealarray("array_name","/tmp/array","#[^\n]*",":",10,4000);
ARGUMENTS:
comment field will strip out unwanted patterns from the file being
read, leaving unstripped characters to be split into fields. The
regex is unanchored See Anchored vs. unanchored regular expressions.
split regex is also unanchored.
Notes:
For detailed notes, See Function readintarray.
Synopsis: readreallist(arg0,arg1,arg2,arg3,arg4) returns type rlist
arg0 : File name to read, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Regex matching comments, in the range .*
arg2 : Regex to split data, in the range .*
arg3 : Maximum number of entries to read, in the range 0,99999999999
arg4 : Maximum bytes to read, in the range 0,99999999999
Read and assign a list variable from a file of separated real numbers
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"mylist" rlist => { readreallist("/tmp/listofreal","#.*","[\n]",10,400) };
reports:
Yr2008::
"List entry: $(mylist)";
}
ARGUMENTS:
comment field will strip out unwanted patterns from the file being
read, leaving unstripped characters to be split into fields. The
regex is unanchored See Anchored vs. unanchored regular expressions.
split regex is also unanchored.
Notes:
Synopsis: readstringarray(arg0,arg1,arg2,arg3,arg4,arg5) returns type int
arg0 : Array identifer to populate, in the range [a-zA-Z0-9_$()\[\].]+
arg1 : File name to read, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg2 : Regex matching comments, in the range .*
arg3 : Regex to split data, in the range .*
arg4 : Maximum number of entries to read, in the range 0,99999999999
arg5 : Maximum bytes to read, in the range 0,99999999999
Read an array of strings from a file and assign the dimension to a variable
Example:
vars:
"dim_array"
int => readstringarray("array_name","/tmp/array","\s*#[^\n]*",":",10,4000);
Returns an integer number of keys in the array (i.e., the number of lines matched). If you only want the fields in the first matching line (e.g., to mimic the behavior of the getpwnam(3) on the file /etc/passwd), See Function getfields instead.
ARGUMENTS:
comment field will strip out unwanted patterns from the file being
read, leaving unstripped characters to be split into fields. The
regex is unanchored See Anchored vs. unanchored regular expressions.
split regex is also unanchored.
Notes:
Reads a two dimensional array from a file. One dimension is separated by the character specified in the argument, the other by the the lines in the file. The first field of the lines names the first array argument.
at:x:25:25:Batch jobs daemon:/var/spool/atjobs:/bin/bash
avahi:x:103:105:User for Avahi:/var/run/avahi-daemon:/bin/false # Disallow login
beagleindex:x:104:106:User for Beagle indexing:/var/cache/beagle:/bin/bash
bin:x:1:1:bin:/bin:/bin/bash
# Daemon has the default shell
daemon:x:2:2:Daemon:/sbin:
Results in a systematically indexed map of the file. Some samples are show below to illustrate the pattern.
...
array_name[daemon][0] daemon
array_name[daemon][1] x
array_name[daemon][2] 2
array_name[daemon][3] 2
array_name[daemon][4] Daemon
array_name[daemon][5] /sbin
array_name[daemon][6] /bin/bash
...
array_name[at][3] 25
array_name[at][4] Batch jobs daemon
array_name[at][5] /var/spool/atjobs
array_name[at][6] /bin/bash
...
array_name[games][3] 100
array_name[games][4] Games account
array_name[games][5] /var/games
array_name[games][6] /bin/bash
...
Synopsis: readstringarrayidx(arg0,arg1,arg2,arg3,arg4,arg5) returns type int
arg0 : Array identifer to populate, in the range [a-zA-Z0-9_$()\[\].]+
arg1 : File name to read, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg2 : Regex matching comments, in the range .*
arg3 : Regex to split data, in the range .*
arg4 : Maximum number of entries to read, in the range 0,99999999999
arg5 : Maximum bytes to read, in the range 0,99999999999
Read an array of strings from a file and assign the dimension to a variable with integer indeces
Example:
vars:
"dim_array"
int => readstringarrayidx("array_name","/tmp/array","\s*#[^\n]*",":",10,4000);
Returns an integer number of keys in the array (i.e., the number of lines matched). If you only want the fields in the first matching line (e.g., to mimic the behavior of the getpwnam(3) on the file /etc/passwd), See Function getfields instead.
ARGUMENTS:
comment field will strip out unwanted patterns from the file being
read, leaving unstripped characters to be split into fields. The
regex is unanchored See Anchored vs. unanchored regular expressions.
split regex is also unanchored.
Notes:
Reads a two dimensional array from a file. One dimension is separated by
the character specified in the argument, the other by the the lines in the file.
The array arguments are both integer indeces, allowing for
non-identifiers at first field (e.g. duplicates or names with spaces),
unlike readstringarray.
at spaced:x:25:25:Batch jobs daemon:/var/spool/atjobs:/bin/bash
duplicate:x:103:105:User for Avahi:/var/run/avahi-daemon:/bin/false # Disallow login
beagleindex:x:104:106:User for Beagle indexing:/var/cache/beagle:/bin/bash
duplicate:x:1:1:bin:/bin:/bin/bash
# Daemon has the default shell
daemon:x:2:2:Daemon:/sbin:
Results in a systematically indexed map of the file. Some samples are show below to illustrate the pattern.
array_name[0][0] at spaced
array_name[0][1] x
array_name[0][2] 25
array_name[0][3] 25
array_name[0][4] Batch jobs daemon
array_name[0][5] /var/spool/atjobs
array_name[0][6] /bin/bash
array_name[1][0] duplicate
array_name[1][1] x
array_name[1][2] 103
array_name[1][3] 105
array_name[1][4] User for Avahi
array_name[1][5] /var/run/avahi-daemon
array_name[1][6] /bin/false
...
Synopsis: readstringlist(arg0,arg1,arg2,arg3,arg4) returns type slist
arg0 : File name to read, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Regex matching comments, in the range .*
arg2 : Regex to split data, in the range .*
arg3 : Maximum number of entries to read, in the range 0,99999999999
arg4 : Maximum bytes to read, in the range 0,99999999999
Read and assign a list variable from a file of separated strings
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
vars:
"mylist" slist => { readstringlist("/tmp/listofstring", "#.*", "\s", 10, 400) };
reports:
Yr2008::
"List entry: $(mylist)";
}
ARGUMENTS:
comment field will strip out unwanted patterns from the file being
read, leaving unstripped characters to be split into fields. The
regex is unanchored See Anchored vs. unanchored regular expressions.
Note that the text is not treated as a collection of lines, but is read
as a single block of maxsize characters, and the regex is applied to
that as a single string.
split regex is also unanchored.
Notes:
The following example file would be split into a list of the first ten Greek letters - alpha through kappa.
alpha beta
gamma # This is a comment
delta epsilon zeta
eta
theta
iota
kappa lambda
mu
nu
etc
Synopsis: readtcp(arg0,arg1,arg2,arg3) returns type string
arg0 : Host name or IP address of server socket, in the range .*
arg1 : Port number, in the range 0,99999999999
arg2 : Protocol query string, in the range .*
arg3 : Maximum number of bytes to read, in the range 0,99999999999
Connect to tcp port, send string and assign result to variable
Example:
bundle agent example
{
vars:
"my80" string => readtcp("research.iu.hio.no","80","GET /index.php HTTP/1.1$(const.r)$(const.n)Host: research.iu.hio.no$(const.r)$(const.n)$(const.r)$(const.n)",20);
classes:
"server_ok" expression => regcmp(".*200 OK.*\n.*","$(my80)");
reports:
server_ok::
"Server is alive";
!server_ok::
"Server is not responding - got $(my80)";
}
Important note: not all Unix TCP read operations respond to signals for interruption so poorly formed requests can hang. Always test TCP connections fully before deploying. When matching multi-line responses, not that regular expressions do not cross newline boundaries.
Notes:
If the send string is empty, no data are sent or received from the socket. Then the function only tests whether the TCP port is alive and returns an empty variable.
Note that on some systems the timeout mechanism does not seem to successfully interrupt the waiting system calls so this might hang if you send a query string that is incorrect. This should not happen, but the cause has yet to be diagnosed.
Synopsis: regarray(arg0,arg1) returns type class
arg0 : CFEngine array identifier, in the range [a-zA-Z0-9_$()\[\].]+
arg1 : Regular expression, in the range .*
True if arg1 matches any item in the associative array with id=arg2
Example:
body common control
{
bundlesequence => { "testbundle" };
}
###########################################
bundle agent testbundle
{
vars:
"myarray[0]" string => "bla1";
"myarray[1]" string => "bla2";
"myarray[3]" string => "bla";
"myarray" string => "345";
"not" string => "345";
classes:
"ok" expression => regarray("myarray","b.*2");
reports:
ok::
"Found in list";
!ok::
"Not found in list";
}
Notes:
Tests whether an associative array contains elements matching a certain regular expression. The result is a class.
ARGUMENTS:
Synopsis: regcmp(arg0,arg1) returns type class
arg0 : Regular expression, in the range .*
arg1 : Match string, in the range .*
True if arg1 is a regular expression matching that matches string arg2
Example:
bundle agent subtest(user)
{
classes:
"invalid" not => regcmp("[a-z]{4}","$(user)");
reports:
!invalid::
"User name $(user) is valid at exactly 4 letters";
invalid::
"User name $(user) is invalid";
}
Notes:
Compares a string to a regular expression.
ARGUMENTS:
If there are multiple-lines in the data, it is necessary to code these
explicitly, as regular expressions do not normally match the end of line
as a regular character (they only match end of string). You can do this using either standard regular
expression syntax or using the additional features of PCRE (where
(?ms) changes the way that ‘.’, ‘^’ and ‘$’ behave), e.g.
body common control
{
bundlesequence => { "example" };
}
bundle agent example
{
vars:
"x" string => "
NAME: apache2 - Apache 2.2 web server
CATEGORY: application
ARCH: all
VERSION: 2.2.3,REV=2006.09.01
BASEDIR: /
VENDOR: http://httpd.apache.org/ packaged for CSW by Cory Omand
PSTAMP: comand@thor-20060901022929
INSTDATE: Dec 14 2006 16:05
HOTLINE: http://www.blastwave.org/bugtrack/
EMAIL: comand@blastwave.org
STATUS: completely installed
";
classes:
"pkg_installed" expression => regcmp("(.*\n)*STATUS:\s+completely installed\n(.*\n)*",$(x));
"base_is_root" expression => regcmp("(?ms).*^BASEDIR:\s+/$.*", $(x));
reports:
pkg_installed::
"installed";
base_is_root::
"in root";
}
Synopsis: regextract(arg0,arg1,arg2) returns type class
arg0 : Regular expression, in the range .*
arg1 : Match string, in the range .*
arg2 : Identifier for back-references, in the range [a-zA-Z0-9_$()\[\].]+
True if the regular expression in arg 1 matches the string in arg2 and sets a non-empty array of backreferences named arg3
Example:
bundle agent testbundle
{
classes:
# Extract regex backreferences and put them in an array
"ok" expression => regextract(
"xx ([^\s]+) ([^\s]+).* xx",
"xx one two three four xx",
"myarray"
);
reports:
ok::
"ok - \"$(myarray[0])\" = xx + \"$(myarray[1])\" + \"$(myarray[2])\" + .. + xx";
}
Notes:
Arguments:
$(identifier[0]) = entire string
$(identifier[1]) = back reference 1, etc
History: This function was introduced in CFEngine version 3.0.4 (2010)
Synopsis: registryvalue(arg0,arg1) returns type string
arg0 : Windows registry key, in the range .*
arg1 : Windows registry value-id, in the range .*
Returns a value for an MS-Win registry key,value pair
Example:
bundle agent reg
{
vars:
"value" string => registryvalue("HKEY_LOCAL_MACHINE\SOFTWARE\CFEngine AS\Cfengine","value3");
reports:
windows::
"Value extracted: $(value)";
}
Notes:
This function applies only to Windows based systems. it reads a data field for the value named in the second argument, which lies within the registry key given by the first argument.
Synopsis: regline(arg0,arg1) returns type class
arg0 : Regular expression, in the range .*
arg1 : Filename to search, in the range .*
True if the regular expression in arg1 matches a line in file arg2
Example:
bundle agent testbundle
{
files:
"/tmp/testfile" edit_line => test;
}
########################################################
bundle edit_line test
{
classes:
"ok" expression => regline(".*XYZ.*","$(edit.filename)");
reports:
ok::
"File $(edit.filename) has a line with \"XYZ\" in it";
}
Notes:
Note that the regular expression must match an entire line of the
file in order to give a true result. This function is useful for
edit_line applications, where one might want to set a class for
detecting the presence of a string which does not exactly match
one being inserted. e.g.
bundle edit_line upgrade_cfexecd
{
classes:
# Check there is not already a crontab line, not identical to
# the one proposed below...
"exec_fix" not => regline(".*cf-execd.*","$(edit.filename)");
insert_lines:
exec_fix::
"0,5,10,15,20,25,30,35,40,45,50,55 * * * * /var/cfengine/bin/cf-execd -F";
reports:
exec_fix::
"Added a 5 minute schedule to crontabs";
}
Synopsis: reglist(arg0,arg1) returns type class
arg0 : CFEngine list identifier, in the range @[(][a-zA-Z0-9]+[)]
arg1 : Regular expression, in the range .*
True if the regular expression in arg2 matches any item in the list whose id is arg1
Example:
vars:
"nameservers" slist => {
"128.39.89.10",
"128.39.74.16",
"192.168.1.103"
};
classes:
"am_name_server" expression => reglist("@(nameservers)",escape("$(sys.ipv4[eth0])"));
Notes:
Matches a list of test strings to a regular expression. In the example above, the IP address in
$(sys.ipv4[eth0]) must be escaped, because if not, the dot (‘.’) characters in the IP address
would be interpreted as regular expression "match any" characters.
ARGUMENTS:
Synopsis: regldap(arg0,arg1,arg2,arg3,arg4,arg5,arg6) returns type class
arg0 : URI, in the range .*
arg1 : Distinguished name, in the range .*
arg2 : Filter, in the range .*
arg3 : Record name, in the range .*
arg4 : Search scope policy, in the range subtree,onelevel,base
arg5 : Regex to match results, in the range .*
arg6 : Security level, in the range none,ssl,sasl
True if the regular expression in arg6 matches a value item in an ldap search
Example:
classes:
"found" expression => regldap(
"ldap://ldap.example.org",
"dc=cfengine,dc=com",
"(sn=User)",
"uid",
"subtree",
"jon.*",
"none"
);
Notes:
(class) regldap(uri,dn,filter,name,scope,regex,security)
|
This function retrieves a single field from all matching LDAP records identified by the search parameters and compares it to a regular expression. If there is a match, true is returned else false.
ARGUMENTS:
"ldap://ldap.cfengine.com.no"
uid.
subtree
onelevel
base
none
ssl
sasl
Synopsis: remotescalar(arg0,arg1,arg2) returns type string
arg0 : Variable identifier, in the range [a-zA-Z0-9_$()\[\].]+
arg1 : Hostname or IP address of server, in the range .*
arg2 : Use enryption, in the range true,false,yes,no,on,off
Read a scalar value from a remote cfengine server
Example:
vars:
"remote" string => remotescalar("test_scalar","127.0.0.1","yes");
Notes:
CFEngine caches the value of this variable, so that, if the network is
unavailable, the last known value will be used. Hence use of this function
is fault tolerant. Care should be taken in attempting to access remote variables
that are not available, as the repeated connections needed to resolve the
absence of a value can lead to undesirable behaviour. As a general rule,
users are recommended to refrain from relying on the availability of network resources.
(string) remotescalar(resource handle,host/IP address,encrypt);
|
This function downloads a string from a remote server, using the promise handle as a variable identifier. Availability: Enterprise editions of CFEngine only.
ARGUMENTS:
true
yes
false
no
Note that this function assumes that you have already performed a
successful key exchange between systems, (e.g. using either a remote
copy or cf-runagent connection). It contains no mechanism for
trust establishment and will fail if there is no trust relationship
pre-established.
Synopsis: remoteclassesmatching(arg0,arg1,arg2,arg3) returns type class
arg0 : Regular expression, in the range .*
arg1 : Server name or address, in the range .*
arg2 : Use encryption, in the range true,false,yes,no,on,off
arg3 : Return class prefix, in the range [a-zA-Z0-9_$()\[\].]+
Read persistent classes matching a regular expression from a remote cfengine server and add them into local context with prefix
Example:
"succeeded" expression => remoteclassesmatching("regex","server","yes","myprefix");
Notes:
This function is only available in Enterprise versions of CFEngine (Nova, Constellation, etc).
This function contacts a remote cf-serverd and requests access to defined
persistent classes on that system. These must be granted access to by making an
access promise with resource_type set to context.
The return value is true (sets the class) if communication with the server was successful and classes are populated in the current bundle with a prefix of your choosing. The arguments are:
Note that this function assumes that you have already performed a successful key exchange between
systems, (e.g. using either a remote copy or cf-runagent connection). It contains no mechanism
for trust establishment and will fail if there is no trust relationship pre-established.
Synopsis: returnszero(arg0,arg1) returns type class
arg0 : Fully qualified command path, in the range "?(([a-zA-Z]:\\.*)|(/.*))
arg1 : Shell encapsulation option, in the range useshell,noshell
True if named shell command has exit status zero
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"my_result" expression => returnszero("/usr/local/bin/mycommand","noshell");
reports:
!my_result::
"Command failed";
}
Notes:
This is the complement of execresult, but it returns a class
result rather than the output of the command.
Synopsis: rrange(arg0,arg1) returns type rrange [real,real]
arg0 : Real number, in the range -9.99999E100,9.99999E100
arg1 : Real number, in the range -9.99999E100,9.99999E100
Define a range of real numbers for cfengine internal use
Example:
?
Notes:
This is not yet used.
Synopsis: selectservers(arg0,arg1,arg2,arg3,arg4,arg5) returns type int
arg0 : The identifier of a cfengine list of hosts or addresses to contact, in the range @[(][a-zA-Z0-9]+[)]
arg1 : The port number, in the range 0,99999999999
arg2 : A query string, in the range .*
arg3 : A regular expression to match success, in the range .*
arg4 : Maximum number of bytes to read from server, in the range 0,99999999999
arg5 : Name for array of results, in the range [a-zA-Z0-9_$()\[\].]+
Select tcp servers which respond correctly to a query and return their number, set array of names
Example:
body common control
{
bundlesequence => { "test" };
}
###########################################################
bundle agent test
{
vars:
"hosts" slist => { "slogans.iu.hio.no", "eternity.iu.hio.no", "nexus.iu.hio.no" };
"fhosts" slist => { "www.cfengine.com", "www.cfengine.org" };
"up_servers" int => selectservers("@(hosts)","80","","","100","alive_servers");
"has_favicon" int =>
selectservers(
"@(hosts)", "80",
"GET /favicon.ico HTTP/1.0$(const.n)Host: www.cfengine.com$(const.n)$(const.n)",
"(?s).*OK.*",
"200", "favicon_servers");
classes:
"someone_alive" expression => isgreaterthan("$(up_servers)","0");
"has_favicon" expression => isgreaterthan("$(has_favicon)","0");
reports:
cfengine_3::
"Number of active servers $(up_servers)";
someone_alive::
"First server $(alive_servers[0]) fails over to $(alive_servers[1])";
has_favicon::
"At least $(favicon_servers[0]) has a favicon.ico";
}
Notes:
This function selects all the TCP ports that are active and functioning from an ordered list and builds an array of their names. This allows us to select a current list of failover alternatives that are pretested.
sendstr is empty, then no query is sent to the server.
(?s)
in the example above, which allows ‘.’ to also match newlines
in the multi-line HTTP response). If regex_on_reply is
empty, then no reply-checking is performed (and any server reply
is deemed to be satisfactory).
array_name[0],.. etc.
Synopsis: splayclass(arg0,arg1) returns type class
arg0 : Input string for classification, in the range .*
arg1 : Splay time policy, in the range daily,hourly
True if the first argument's time-slot has arrived, according to a policy in arg2
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"my_result" expression => splayclass("$(sys.host)$(sys.ipv4)","daily");
reports:
my_result::
"Load balanced class activated";
}
Notes:
The lvalue class evaluates to true if the system clock lies within a scheduled time-interval that maps to a hash of the first argument (which may be any arbitrary string). Different strings will hash to different time intervals, and thus one can map different tasks to time-intervals.
This function may be used to distribute a task, typically in multiple hosts,
in time over a day or
an hourly period, depending on the policy in the second argument (which must
be one of "daily" or "hourly").
This is useful for copying resources to multiple hosts from a single server,
(e.g. large software updates), when simultaneous scheduling would lead to a
bottleneck and/or server overload.
The function is similar to the splaytime feature in cf-execd,
except
that it allows you to base the decision on any string-criterion on a
given host. The entropy (or string-variation) in the first argument
determines how effectively cfengine will be able to distribute tasks.
CFEngine instances with the same first argument will yield a true
result at the same time (and different first argument will yield a true
result at a different time). Thus tasks could be scheduled according to
group names for predictability, or according to IP addresses for
distribution across the policy interval.
The times at which the splayclass will be defined depends on the second
argument. If the first argument is "hourly" then the class will be
defined for a 5-minute interval every hour (and if the first argument is
"daily", then the class will be defined for one 5-minute interval
every day. This means that splayclass assumes that you are running
CFEngine with the default schedule of "every 5 minutes". If you change the
executor schedule control variable, you may prevent the splayclass
from ever being defined (that is, if the hashed 5-minute interval that is
selected by the splayclass is a time when you have told CFEngine not to
run).
Synopsis: splitstring(arg0,arg1,arg2) returns type slist
arg0 : A data string, in the range .*
arg1 : Regex to split on, in the range .*
arg2 : Maximum number of pieces, in the range 0,99999999999
Convert a string in arg1 into a list of max arg3 strings by splitting on a regular expression in arg2
Example:
bundle agent test
{
vars:
"split1" slist => splitstring("one:two:three",":","10");
"split1" slist => splitstring("one:two:three",":","1");
"split3" slist => splitstring("alpha:xyz:beta","xyz","10");
reports:
linux::
"split1: $(split1)"; # will list "one", "two", and "three"
"split2: $(split2)"; # will list "one" and "two:three"
"split3: $(split3)"; # will list "alpha:" and ":beta"
}
Notes:
Returns a list of strings from a string.
ARGUMENTS:
If the maximum number of splits is insufficient to accomodate all entries, the final entry in the slist that is generated will contain the rest of the unsplit string.
Synopsis: strcmp(arg0,arg1) returns type class
arg0 : String, in the range .*
arg1 : String, in the range .*
True if the two strings match exactly
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"same" expression => strcmp("test","test");
reports:
same::
"Strings are equal";
!same::
"Strings are not equal";
}
Notes:
Synopsis: sum(arg0) returns type real
arg0 : A list of arbitrary real values, in the range [a-zA-Z0-9_$()\[\].]+
Return the sum of a list of reals
Example:
body common control
{
bundlesequence => { "test" };
}
##############################
bundle agent test
{
vars:
"adds_to_six" ilist => { "1", "2", "3" };
"six" real => sum("adds_to_six");
"adds_to_zero" rlist => { "1.0", "2", "-3e0" };
"zero" real => sum("adds_to_zero");
reports:
cfengine_3::
"six is $(six), zero is $(zero)";
}
Because $(six) and $(zero) are both real numbers, the report
that is generated will be:
six is 6.000000, zero is 0.000000
Notes:
Of course, you could easily combine sum with readstringarray or
readreallist, etc. to collect summary information from a source
external to CFEngine.
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
This function might be used for simple ring computation.
Synopsis: translatepath(arg0) returns type string
arg0 : Unix style path, in the range "?(([a-zA-Z]:\\.*)|(/.*))
Translate path separators from Unix style to the host's native
Example:
body common control
{
bundlesequence => { "test" };
}
##############################
bundle agent test
{
vars:
"inputs_dir" string => translatepath("$(sys.workdir)/inputs");
reports:
windows::
"The path has backslashes: $(inputs_dir)";
!windows::
"The path has slashes: $(inputs_dir)";
}
Notes:
Takes a string argument with slashes as path separators and translate these to the native format for path separators on the host. For example translatepath("a/b/c") would yield "a/b/c" on Unix platforms, but "a\b\c" on Windows.
Be careful when using this function in combination with regular expressions, since backslash is also used as escape character in regex's. For example, in the regex ‘dir/.abc’, the dot represents the regular expression "any character", while in the regex ‘dir\.abc’, the backslash-dot represents a literal dot character.
Synopsis: usemodule(arg0,arg1) returns type class
arg0 : Name of module command, in the range .*
arg1 : Argument string for the module, in the range .*
Execute cfengine module script and set class if successful
Example:
body common control
{
any::
bundlesequence => {
test
};
}
###################################################################
bundle agent test
{
classes:
# returns $(user)
"done" expression => usemodule("getusers","");
commands:
"/bin/echo promiser text" args => "test $(user)";
}
Notes:
Modules must reside in WORKDIR/modules but no longer require a special naming convention.
ARGUMENTS:
Synopsis: userexists(arg0) returns type class
arg0 : User name or identifier, in the range .*
True if user name or numerical id exists on this host
Example:
body common control
{
bundlesequence => { "example" };
}
###########################################################
bundle agent example
{
classes:
"ok" expression => userexists("root");
reports:
ok::
"Root exists";
!ok::
"Root does not exist";
}
Notes:
Checks whether the user is in the password database for the current host. The argument must be a user name or user id.
const
CFEngine defines a number of variables for embedding unprintable values or values with special meanings in strings.
reports: some:: # This will report: The value of $(const.dollar) is $ "The value of $(const.dollar)(const.dollar) is $(const.dollar)"; # This will report: But the value of \$(dollar) is \$(dollar) "But the value of \$(dollar) is \$(dollar)";
reports: cfengine_3:: "A newline with either $(const.n) or with $(const.endl) is ok"; "But a string with \n in it does not have a newline!";
reports: cfengine_3:: "A newline with either $(const.n) or with $(const.endl) is ok"; "But a string with \n in it does not have a newline!";
reports: cfengine_3:: "A carriage return character is $(const.r)";
reports: cfengine_3:: "A report with a$(const.t)tab in it";
edit
This context ‘edit’ is used to access information about editing promises during their execution. It is context dependent and not universally meaningful or available. For example:
bundle agent testbundle
{
files:
"/tmp/testfile"
edit_line => test;
}
#
bundle edit_line test
{
classes:
"ok" expression => regline(".*mark.*","$(edit.filename)");
reports:
ok::
"File matched $(edit.filename)";
}
$(edit.filename)
This variable points to the filename of the file currently making an edit promise. If the file has been arrived at through a search, this could be different from the files promiser.
This variable points to the filename of the file currently making an edit promise. If the file has been arrived at through a search, this could be different from the files promiser.
match
Each time cfengine matches a string, these values are
assigned to a special variable context $(match.n).
The fragments can be referred to in the remainder of the promise.
There are two places where this makes sense. One is in pattern replacement
during file editing, and the other is in searching for files.
Consider the examples below:
bundle agent testbundle
{
files:
"/home/mark/tmp/(cf[23])_(.*)"
create => "true",
edit_line => myedit("second $(match.2)");
# but more specifically...
"/home/mark/tmp/cf3_(test)"
create => "true",
edit_line => myedit("second $(match.1)");
}
A string matching the complete regular expression whether or not back-references were used in the pattern.
mon
The variables discovered by cf-monitord are placed in this monitoring
context. Monitoring variables are expected to be ephemeral properties, rapidly changing.
In enterprise versions of cfengine, custom defined monitoring targets also become variables in this context, named by the handle of the promise that defined them.
Observational measure collected every 2.5 minutes from cf-monitord, description: Users with active processes.
Observational measure collected every 2.5 minutes from cf-monitord, description: Users with active processes.
Observational measure collected every 2.5 minutes from cf-monitord, description: Users with active processes.
Observational measure collected every 2.5 minutes from cf-monitord, description: Sum privileged system processes.
Observational measure collected every 2.5 minutes from cf-monitord, description: Sum privileged system processes.
Observational measure collected every 2.5 minutes from cf-monitord, description: Sum privileged system processes.
Observational measure collected every 2.5 minutes from cf-monitord, description: Sum non-privileged process.
Observational measure collected every 2.5 minutes from cf-monitord, description: Sum non-privileged process.
Observational measure collected every 2.5 minutes from cf-monitord, description: Sum non-privileged process.
Observational measure collected every 2.5 minutes from cf-monitord, description: Free disk on / partition.
Observational measure collected every 2.5 minutes from cf-monitord, description: Free disk on / partition.
Observational measure collected every 2.5 minutes from cf-monitord, description: Free disk on / partition.
Observational measure collected every 2.5 minutes from cf-monitord, description: % kernel load utilization.
Observational measure collected every 2.5 minutes from cf-monitord, description: % kernel load utilization.
Observational measure collected every 2.5 minutes from cf-monitord, description: % kernel load utilization.
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name lookups (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name lookups (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name lookups (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name lookups (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name lookups (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name lookups (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name datagrams (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name datagrams (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name datagrams (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name datagrams (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name datagrams (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name datagrams (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name sessions (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name sessions (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name sessions (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name sessions (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name sessions (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: netbios name sessions (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: IRC connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: IRC connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: IRC connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: IRC connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: IRC connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: IRC connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: cfengine connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: cfengine connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: cfengine connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: cfengine connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: cfengine connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: cfengine connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: nfs connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: nfs connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: nfs connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: nfs connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: nfs connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: nfs connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: smtp connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: smtp connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: smtp connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: smtp connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: smtp connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: smtp connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: www connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: www connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: www connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: www connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: www connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: www connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ftp connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ftp connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ftp connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ftp connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ftp connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ftp connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ssh connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ssh connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ssh connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ssh connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ssh connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ssh connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: wwws connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: wwws connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: wwws connections (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: wwws connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: wwws connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: wwws connections (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ICMP packets (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ICMP packets (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ICMP packets (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: ICMP packets (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ICMP packets (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: ICMP packets (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: UDP dgrams (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: UDP dgrams (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: UDP dgrams (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: UDP dgrams (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: UDP dgrams (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: UDP dgrams (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: DNS requests (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: DNS requests (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: DNS requests (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: DNS requests (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: DNS requests (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: DNS requests (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP sessions (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP sessions (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP sessions (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP sessions (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP sessions (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP sessions (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP acks (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP acks (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP acks (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP acks (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP acks (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP acks (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP finish (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP finish (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP finish (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP finish (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP finish (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP finish (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP misc (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP misc (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP misc (in).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP misc (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP misc (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: TCP misc (out).
Observational measure collected every 2.5 minutes from cf-monitord, description: Webserver hits.
Observational measure collected every 2.5 minutes from cf-monitord, description: Webserver hits.
Observational measure collected every 2.5 minutes from cf-monitord, description: Webserver hits.
Observational measure collected every 2.5 minutes from cf-monitord, description: Webserver errors.
Observational measure collected every 2.5 minutes from cf-monitord, description: Webserver errors.
Observational measure collected every 2.5 minutes from cf-monitord, description: Webserver errors.
Observational measure collected every 2.5 minutes from cf-monitord, description: New log entries (Syslog).
Observational measure collected every 2.5 minutes from cf-monitord, description: New log entries (Syslog).
Observational measure collected every 2.5 minutes from cf-monitord, description: New log entries (Syslog).
Observational measure collected every 2.5 minutes from cf-monitord, description: New log entries (messages).
Observational measure collected every 2.5 minutes from cf-monitord, description: New log entries (messages).
Observational measure collected every 2.5 minutes from cf-monitord, description: New log entries (messages).
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 0.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 0.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 0.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 1.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 1.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 1.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 2.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 2.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 2.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 3.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 3.
Observational measure collected every 2.5 minutes from cf-monitord, description: CPU Temperature 3.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization (all).
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization (all).
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization (all).
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 0.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 0.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 0.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 1.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 1.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 1.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 2.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 2.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 2.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 3.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 3.
Observational measure collected every 2.5 minutes from cf-monitord, description: %CPU utilization 3.
sys
System variables are derived from cfengine's automated discovery of system values. They are provided as variables in order to make automatically adaptive rules for configuration, e.g.
files:
any::
"$(sys.resolv)"
create => "true",
edit_line => doresolv("@(this.list1)","@(this.list2)"),
edit_defaults => reconstruct;
The above rule requires no class specification because the variable itself is class-specific.
The variable gives the kernel's short architecture description.
# arch = x86_64
The date of the system in canonical form, i.e. in the form of a class.
# cdate = Sun_Dec__7_10_39_53_2008_
A variable containing the path to the cfengine agent cf-agent
on the platform you are using.
body executor control
{
exec_command => "$(sys.cf_twin) -f failsafe.cf && $(sys.cf_agent)";
}
A variable containing the path to the cfengine executor cf-execd
on the platform you are using.
commands: "$(sys.cf_execd)";
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
reports:
cfengine_3::
"The hub path is $(sys.cf_hub)";
The path of the cf-hub program.
A variable containing the path to the cfengine key generator cf-key
on the platform you are using.
commands: "$(sys.cf_key)";
A variable containing the path to the cfengine knowledge agent cf-know
on the platform you are using.
commands: "$(sys.cf_know) -f ./build_docs.cf -sg";
A variable containing the path to the cfengine monitoring daemon cf-monitord
on the platform you are using.
commands: restart_monitord:: "$(sys.cf_monitord)";
A variable containing the path to the cfengine syntax analyxer cf-promises
on the platform you are using.
classes:
"syntax_ok" expression => returnszero("$(sys.cf_promises)");
reports:
cfengine_3::
"The reporter path is $(sys.cf_report)";
The path of the cf-report program.
This variable is used for completeness, but it is unlikely to be called from
within cfengine. It contains the full path to the interactive progam
cf-runagent.
A variable containing the path to the cfengine server daemon cf-serverd
on the platform you are using.
commands: restart_serverd:: "$(sys.cf_serverd)";
A variable containing the path to the cfengine agent's twin
cf-twin on the platform you are using. A twin is simply a
second copy of the agent in CFEngine's work directory ‘bin’ area,
used during upgrades and cases where modification of the
cf-agent binary could be attempted (this is not allowed on some
platforms, such as Windows).
body executor control
{
exec_command => "$(sys.cf_twin) -f failsafe.cf && $(sys.cf_agent)";
}
The variable gives the version of the running CFEngine Community Edition.
# cf_version = 3.0.5
This variable contains the name of the hard-class category for this host, i.e. its top level operating system type classification.
# class = linux
The date of the system as a text string.
# date = Sun Dec 7 10:39:53 2008
The domain name as divined by cfengine. If the DNS is in use, it could
be possible to derive the domain name from its DNS regisration, but in
general there is no way to discover this value automatically. The
common control body permits the ultimate specification of this
value.
# domain = example.org
reports: nova:: "License expires $(sys.expires)";
The location of the system NFS exports file.
# exports = /etc/exports # exports = /etc/dfs/dfstab
The fully qualified name of the host. In order to compute this value properly, the domain name must be defined.
# fqhost = host.example.org
The location of the system filesystem (mount) table.
# fstab = /etc/fstab
The name of the current host, according to the kernel. It is undefined whether this is qualified or unqualified with a domain name.
# host = myhost
The assumed (default) name of the main system interface on this host.
# interface = eth0
All four octets of the IPv4 address of the first system interface.
Note:
If your system has a single ethernet interface, ‘$(sys.ipv4)’ will contain your IPv4 address. However, if your system has multiple interfaces, then ‘$(sys.ipv4)’ will simply be the IPv4 address of the first interface in the list that has an assigned address; See Variable sys.ipv4[interface_name], for details on obtaining the IPv4 addresses of all interfaces on a system.
The full IPv4 address of the system interface named as the associative array index, e.g. ‘$(ipv4[le0])’ or ‘$(ipv4[xr1])’.
# If the IPv4 address on the interfaces are # le0 = 192.168.1.101 # xr1 = 10.12.7.254 # # Then the octets of all interfaces are accessable as an associative array # ipv4_1[le0] = 192 # ipv4_2[le0] = 192.168 # ipv4_3[le0] = 192.168.1 # ipv4[le0] = 192.168.1.101 # ipv4_1[xr1] = 10 # ipv4_2[xr1] = 10.12 # ipv4_3[xr1] = 10.12.7 # ipv4[xr1] = 10.12.7.254
Note:
The list of interfaces may be acquired with ‘getindices("sys.ipv4")’ (or from any of the other associative arrays). Only those interfaces which are marked as "up" and have an IP address will be listed.
The first octet of the IPv4 address of the system interface named as the associative array index, e.g. ‘$(ipv4_1[le0])’ or ‘$(ipv4_1[xr1])’, See Variable sys.ipv4[interface_name].
The first two octets of the IPv4 address of the system interface named as the associative array index, e.g. ‘$(ipv4_2[le0])’ or ‘$(ipv4_2[xr1])’, See Variable sys.ipv4[interface_name].
The first three octets of the IPv4 address of the system interface named as the associative array index, e.g. ‘$(ipv4_3[le0])’ or ‘$(ipv4_3[xr1])’, See Variable sys.ipv4[interface_name].
Contains the unique identifier of the current host.
reports: cfengine_3_1:: "My digest is $(sys.key_digest)";
The long architecture name for this system kernel. This name is sometimes quite unwieldy but can be useful for logging purposes.
# long_arch = linux_x86_64_2_6_22_19_0_1_default__1_SMP_2008_10_14_22_17_43__0200
The name of the system email spool directory.
# maildir = /var/spool/mail
The variable gives the version of the running CFEngine Nova Edition.
# nova_version = 1.1.3
The name of the operating system according to the kernel.
# os = linux
Another name for the operating system.
# ostype = linux_x86_64
History: Was introduced in version 3.1.0b1,Nova 2.0.0b1 (2010)
reports: "Policy hub is $(sys.policy_hub)";
The kernel release of the operating system.
# release = 2.6.22.19-0.1-default
The location of the system resolver file.
# resolv = /etc/resolv.conf
The unqualified name of the current host. See also sys.fqhost.
# uqhost = myhost
On the Windows version of CFEngine Nova, this is the path to the Windows directory of this system.
# windir = C:\WINDOWS
On the Windows version of CFEngine Nova, this is the path to the program files directory of the system.
# winprogdir = C:\Program Files
On 64 bit Windows versions of CFEngine Nova, this is the path to the 32 bit (x86) program files directory of the system.
# winprogdir86 = C:\Program Files (x86)
On the Windows version of CFEngine Nova, this is the path to the Windows system directory.
# winsysdir = C:\WINDOWS\system32
The location of the CFEngine work directory and cache. For the system privileged user this is normally:
# workdir = /var/cfengine
For non-privileged users it is in the user's home directory:
# workdir = /home/user/.cfagent
On the Windows version of CFEngine Nova, it is normally under program files (the directory name may change with the language of Windows):
# workdir = C:\Program Files\Cfengine
this
This context ‘this’ is used to access information about promises
during their execution. It is context dependent and not universally
meaningful or available, but provides a context for variables where one is
needed (such as when passing the value of a list variable into a parameterized
edit_line promise from a file promise). For example:
bundle agent resolver(s,n)
{
files:
"$(sys.resolv)"
create => "true",
edit_line => doresolv("@(this.s)","@(this.n)"),
edit_defaults => reconstruct;
}
$(this.filename)
This variable reveals the name of the file in which the current promise is defined.
$(this.handle)
This variable points to the promise handle of the currently handled promise; it is useful for referring to the intention in log messages.
$(this.line)
This variable reveals the line number in the file at which the current promise is defined.
$(this.promiser)
The special variable $(this.promiser) is used to refer to the current
value of the promiser itself. This is useful in files promises, for
instance when using pattern matching or depth_search that implicitly
match multiple objects. In that case, $(this.promiser) refers to the
currently identified file that makes the promise. For example:
bundle agent find666
{
files:
"/home"
file_select => world_writeable,
transformer => "/bin/echo DETECTED $(this.promiser)",
depth_search => recurse("inf");
"/etc/.*"
file_select => world_writeable,
transformer => "/bin/echo DETECTED $(this.promiser)";
}
body file_select world_writeable
{
search_mode => { "o+w" };
file_result => "mode";
}
CFEngine writes numerous logs and records to its private workspace, referred to as WORKDIR. This chapter makes some brief notes about these files. CFEngine approaches monitoring and reporting from the viewpoint of scalability so there is no default centralizatio of reporting information, as this is untenable for more than a few hundred hosts. Instead, in the classic cfengine way, every host is reponsible for its own data. Solutions for centralization and netwide reporting will be given elsewhere.
The filenames referred to in this section are all relative to the cfengine work directory WORKDIR.
The embedded databases can be viewed and printed using the reporting
tool cf-report.
Their file extensions will vary based on which library is used to
implement them; either Tokyo Cabinet (.tcdb), Quick Database
Manager (.qdbm), or Berkeley DB (.db). Converting one
database format to another is not handled by CFEngine, but there exist
external tools meant for that purpose.
cf-agent.
Most promises take an immeasurablely short time to check, but longer
tasks such as command execution and file copying are measured by default.
Other checks can be instrumented by setting a measurement_class
in the action body of a promise.
cf-monitord.
The outputs directory contains a time-stamped list of outputs
generated by cf-agent. These are collected by cf-execd
and are often E-mailed as reports. However, not all hosts have an
E-mail capability or are online, so the reports are kept here. Reports
are not tidied automatically, so you should delete these files after a
time to avoid a build up.
The cfengine components keep their current process identifier number in `pid files' in the work directory: e.g.
cf-execd.pid cf-serverd.pid
Most other state data refer to the running condition of the host and
are generated by cf-monitord (cfenvd in earlier versions
of cfengine).
cf-agent in reports with showstate.
Table of Contents
common control promises
agent control promises
abortclasses
abortbundleclasses
addclasses
agentaccess
agentfacility
auditing
binarypaddingchar
bindtointerface
hashupdates
childlibpath
checksum_alert_time
defaultcopytype
dryrun
editbinaryfilesize
editfilesize
environment
exclamation
expireafter
files_single_copy
files_auto_define
hostnamekeys
ifelapsed
inform
intermittency
max_children
maxconnections
mountfilesystems
nonalphanumfiles
repchar
default_repository
secureinput
sensiblecount
sensiblesize
skipidentify
suspiciousnames
syslog
track_value
timezone
default_timeout
verbose
server control promises
cfruncommand
maxconnections
denybadclocks
allowconnects
denyconnects
allowallconnects
trustkeysfrom
allowusers
dynamicaddresses
skipverify
logallconnections
logencryptedtransfers
hostnamekeys
auditing
bindtointerface
serverfacility
port
keycacheTTL
monitor control promises
runagent control promises
executor control promises
knowledge control promises
build_directory
document_root
generate_manual
graph_directory
graph_output
html_banner
html_footer
id_prefix
manual_source_directory
query_engine
query_output
sql_type
sql_database
sql_owner
sql_passwd
sql_server
sql_connection_db
style_sheet
view_projections
reporter control promises
hub control promises
common
agent
commands promises in ‘agent’
databases promises in ‘agent’
environments promises in ‘agent’
files promises in ‘agent’
acl (compound body)
changes (compound body)
copy_from (compound body)
create
delete (compound body)
depth_search (compound body)
edit_line
edit_xml
edit_defaults (compound body)
file_select (compound body)
link_from (compound body)
move_obstructions
pathtype
perms (compound body)
rename (compound body)
repository
touch
transformer
* promises in ‘edit_line’
delete_lines promises in ‘edit_line’
insert_lines promises in ‘edit_line’
field_edits promises in ‘edit_line’
replace_patterns promises in ‘edit_line’
interfaces promises in ‘agent’
methods promises in ‘agent’
outputs promises in ‘agent’
packages promises in ‘agent’
processes promises in ‘agent’
services promises in ‘agent’
storage promises in ‘agent’
server
knowledge
monitor
const
edit
match
mon
sys
this