Execution of arbitrary commands
The cmd state module manages the enforcement of executed commands, this
state can tell a command to run under certain circumstances.
A simple example to execute a command:
date > /tmp/salt-run:
cmd.run
Only run if another execution failed, in this case truncate syslog if there is
no disk space:
> /var/log/messages:
cmd.run:
- unless: echo 'foo' > /tmp/.test
Note that when executing a command or script, the state (i.e., changed or not)
of the command is unknown to Salt's state system. Therefore, by default, the
cmd state assumes that any command execution results in a changed state.
This means that if a cmd state is watched by another state then the
state that's watching will always be executed due to the changed state in
the cmd state.
Many state functions in this module now also accept a stateful argument.
If stateful is specified to be true then it is assumed that the command
or script will determine its own state and communicate it back by following
a simple protocol described below:
If there's nothing in the stdout of the command, then assume no
changes. Otherwise, the stdout must be either in JSON or its last
non-empty line must be a string of key=value pairs delimited by spaces (no
spaces on either side of =).
If it's JSON then it must be a JSON object (e.g., {}). If it's
key=value pairs then quoting may be used to include spaces. (Python's shlex
module is used to parse the key=value string)
Two special keys or attributes are recognized in the output:
changed: bool (i.e., 'yes', 'no', 'true', 'false', case-insensitive)
comment: str (i.e., any string)
So, only if changed is True then assume the command execution has
changed the state, and any other key values or attributes in the output will
be set as part of the changes.
If there's a comment then it will be used as the comment of the
state.
Here's an example of how one might write a shell script for use with a
stateful command:
#!/bin/bash
#
echo "Working hard..."
# writing the state line
echo # an empty line here so the next line will be the last.
echo "changed=yes comment='something has changed' whatever=123"
And an example SLS file using this module:
Run myscript:
cmd.run:
- name: /path/to/myscript
- cwd: /
- stateful: True
Run only if myscript changed something:
cmd.wait:
- name: echo hello
- cwd: /
- watch:
- cmd: Run myscript
Note that if the cmd.wait state also specifies stateful: True it can
then be watched by some other states as well.
cmd.wait is not restricted to watching only cmd states. For example
it can also watch a git state for changes
# Watch for changes to a git repo and rebuild the project on updates
my-project:
git.latest:
- name: git@github.com/repo/foo
- target: /opt/foo
- rev: master
cmd.wait:
- name: make install
- cwd: /opt/foo
- watch:
- git: my-project
These two states are often confused. The important thing to remember about them
is that cmd.run states are run each time the SLS
file that contains them is applied. If it is more desirable to have a command
that only runs after some other state changes, then cmd.wait does just that. cmd.wait
is designed to watch other states, and is
executed when the state it is watching changes. Example:
/usr/local/bin/postinstall.sh:
cmd:
- wait
- watch:
- pkg: mycustompkg
file:
- managed
- source: salt://utils/scripts/postinstall.sh
mycustompkg:
pkg:
- installed
- require:
- file: /usr/local/bin/postinstall.sh
-
salt.states.cmd.call(name, func, args=(), kws=None, onlyif=None, unless=None, **kwargs)
Invoke a pre-defined Python function with arguments specified in the state
declaration. This function is mainly used by the
salt.renderers.pydsl renderer.
The interpretation of onlyif and unless arguments are identical to
those of salt.states.cmd.run(), and all other arguments(cwd,
runas, ...) allowed by cmd.run are allowed here, except that their
effects apply only to the commands specified in onlyif and unless
rather than to the function to be invoked.
In addition the stateful argument has no effects here.
The return value of the invoked function will be interpreted as follows.
If it's a dictionary then it will be passed through to the state system,
which expects it to have the usual structure returned by any salt state
function.
Otherwise, the return value(denoted as result in the code below) is
expected to be a JSON serializable object, and this dictionary is returned:
{ 'changes': { 'retval': result },
'result': True if result is None else bool(result),
'comment': result if isinstance(result, basestring) else ''
}
-
salt.states.cmd.mod_watch(name, **kwargs)
Execute a cmd function based on a watch call
-
salt.states.cmd.run(name, onlyif=None, unless=None, cwd=None, user=None, group=None, shell=None, env=(), stateful=False, umask=None, quiet=False, timeout=None, **kwargs)
Run a command if certain circumstances are met
- name
- The command to execute, remember that the command will execute with the
path and permissions of the salt-minion.
- onlyif
- A command to run as a check, run the named command only if the command
passed to the onlyif option returns true
- unless
- A command to run as a check, only run the named command if the command
passed to the unless option returns false
- cwd
- The current working directory to execute the command in, defaults to
/root
- user
- The user name to run the command as
- group
- The group context to run the command as
- shell
- The shell to use for execution, defaults to the shell grain
- env
- Pass in a list or dict of environment variables to be applied to the
command upon execution
- stateful
- The command being executed is expected to return data about executing
a state
- umask
- The umask (in octal) to use when running the command.
- quiet
- The command will be executed quietly, meaning no log entries of the
actual command or its return data
- timeout
- If the command has not terminated after timeout seconds, send the
subprocess sigterm, and if sigterm is ignored, follow up with sigkill
-
salt.states.cmd.script(name, source=None, template=None, onlyif=None, unless=None, cwd=None, user=None, group=None, shell=None, env=None, stateful=False, umask=None, timeout=None, **kwargs)
Download a script from a remote source and execute it. The name can be the
source or the source value can be defined.
- source
- The source script being downloaded to the minion, this source script is
hosted on the salt master server. If the file is located on the master
in the directory named spam, and is called eggs, the source string is
salt://spam/eggs
- template
- If this setting is applied then the named templating engine will be
used to render the downloaded file, currently jinja, mako, and wempy
are supported
- name
- The command to execute, remember that the command will execute with the
path and permissions of the salt-minion.
- onlyif
- A command to run as a check, run the named command only if the command
passed to the onlyif option returns true
- unless
- A command to run as a check, only run the named command if the command
passed to the unless option returns false
- cwd
- The current working directory to execute the command in, defaults to
/root
- user
- The user name to run the command as
- group
- The group context to run the command as
- shell
- The shell to use for execution, defaults to the shell grain
- env
- Pass in a list or dict of environment variables to be applied to the
command upon execution
- umask
- The umask (in octal) to use when running the command.
- stateful
- The command being executed is expected to return data about executing
a state
- timeout
- If the command has not terminated after timeout seconds, send the
subprocess sigterm, and if sigterm is ignored, follow up with sigkill
- args
- String of command line args to pass to the script. Only used if no
args are specified as part of the name argument.
-
salt.states.cmd.wait(name, onlyif=None, unless=None, cwd=None, user=None, group=None, shell=None, stateful=False, umask=None, **kwargs)
Run the given command only if the watch statement calls it
- name
- The command to execute, remember that the command will execute with the
path and permissions of the salt-minion.
- onlyif
- A command to run as a check, run the named command only if the command
passed to the onlyif option returns true
- unless
- A command to run as a check, only run the named command if the command
passed to the unless option returns false
- cwd
- The current working directory to execute the command in, defaults to
/root
- user
- The user name to run the command as
- group
- The group context to run the command as
- shell
- The shell to use for execution, defaults to /bin/sh
- umask
- The umask (in octal) to use when running the command.
- stateful
- The command being executed is expected to return data about executing
a state
-
salt.states.cmd.wait_call(name, func, args=(), kws=None, onlyif=None, unless=None, stateful=False, **kwargs)
-
salt.states.cmd.wait_script(name, source=None, template=None, onlyif=None, unless=None, cwd=None, user=None, group=None, shell=None, env=None, stateful=False, umask=None, **kwargs)
Download a script from a remote source and execute it only if a watch
statement calls it.
- source
- The source script being downloaded to the minion, this source script is
hosted on the salt master server. If the file is located on the master
in the directory named spam, and is called eggs, the source string is
salt://spam/eggs
- template
- If this setting is applied then the named templating engine will be
used to render the downloaded file, currently jinja, mako, and wempy
are supported
- name
- The command to execute, remember that the command will execute with the
path and permissions of the salt-minion.
- onlyif
- A command to run as a check, run the named command only if the command
passed to the onlyif option returns true
- unless
- A command to run as a check, only run the named command if the command
passed to the unless option returns false
- cwd
- The current working directory to execute the command in, defaults to
/root
- user
- The user name to run the command as
- group
- The group context to run the command as
- shell
- The shell to use for execution, defaults to the shell grain
- env
- The root directory of the environment for the referencing script. The
environments are defined in the master config file.
- umask
- The umask (in octal) to use when running the command.
- stateful
- The command being executed is expected to return data about executing
a state