Salt can be controlled by a command line client by the root user on the Salt master. The Salt command line client uses the Salt client API to communicate with the Salt master server. The Salt client is straightforward and simple to use.
Using the Salt client commands can be easily sent to the minions.
Each of these commands accepts an explicit --config option to point to either
the master or minion configuration file. If this option is not provided and
the default configuration file does not exist then Salt falls back to use the
environment variables SALT_MASTER_CONFIG
and SALT_MINION_CONFIG
.
See also
The Salt command needs a few components to send information to the Salt minions. The target minions need to be defined, the function to call and any arguments the function requires.
The first argument passed to salt, defines the target minions, the target minions are accessed via their hostname. The default target type is a bash glob:
salt '*foo.com' sys.doc
Salt can also define the target minions with regular expressions:
salt -E '.*' cmd.run 'ls -l | grep foo'
Or to explicitly list hosts, salt can take a list:
salt -L foo.bar.baz,quo.qux cmd.run 'ps aux | grep foo'
The simple target specifications, glob, regex, and list will cover many use cases, and for some will cover all use cases, but more powerful options exist.
The Grains interface was built into Salt to allow minions to be targeted by system properties. So minions running on a particular operating system can be called to execute a function, or a specific kernel.
Calling via a grain is done by passing the -G option to salt, specifying a grain and a glob expression to match the value of the grain. The syntax for the target is the grain key followed by a globexpression: "os:Arch*".
salt -G 'os:Fedora' test.ping
Will return True from all of the minions running Fedora.
To discover what grains are available and what the values are, execute the grains.item salt function:
salt '*' grains.items
more info on using targeting with grains can be found here.
New in version 0.9.5.
Multiple target interfaces can be used in conjunction to determine the command targets. These targets can then be combined using and or or statements. This is well defined with an example:
salt -C 'G@os:Debian and webser* or E@db.*' test.ping
In this example any minion who's id starts with webser
and is running
Debian, or any minion who's id starts with db will be matched.
The type of matcher defaults to glob, but can be specified with the
corresponding letter followed by the @
symbol. In the above example a grain
is used with G@
as well as a regular expression with E@
. The
webser*
target does not need to be prefaced with a target type specifier
because it is a glob.
more info on using compound targeting can be found here.
New in version 0.9.5.
For certain cases, it can be convenient to have a predefined group of minions on which to execute commands. This can be accomplished using what are called nodegroups. Nodegroups allow for predefined compound targets to be declared in the master configuration file, as a sort of shorthand for having to type out complicated compound expressions.
nodegroups:
group1: 'L@foo.domain.com,bar.domain.com,baz.domain.com and bl*.domain.com'
group2: 'G@os:Debian and foo.domain.com'
group3: 'G@os:Debian and N@group1'
The function to call on the specified target is placed after the target specification.
New in version 0.9.8.
Functions may also accept arguments, space-delimited:
salt '*' cmd.exec_code python 'import sys; print sys.version'
Optional, keyword arguments are also supported:
salt '*' pip.install salt timeout=5 upgrade=True
They are always in the form of kwarg=argument
.
Arguments are formatted as YAML:
salt '*' cmd.run 'echo "Hello: $FIRST_NAME"' env='{FIRST_NAME: "Joe"}'
Note: dictionaries must have curly braces around them (like the env
keyword argument above). This was changed in 0.15.1: in the above example,
the first argument used to be parsed as the dictionary
{'echo "Hello': '$FIRST_NAME"'}
. This was generally not the expected
behavior.
If you want to test what parameters are actually passed to a module, use the
test.arg_repr
command:
salt '*' test.arg_repr 'echo "Hello: $FIRST_NAME"' env='{FIRST_NAME: "Joe"}'
The Salt functions are self documenting, all of the function documentation can
be retried from the minions via the sys.doc()
function:
salt '*' sys.doc
If a series of commands needs to be sent to a single target specification then the commands can be sent in a single publish. This can make gathering groups of information faster, and lowers the stress on the network for repeated commands.
Compound command execution works by sending a list of functions and arguments instead of sending a single function and argument. The functions are executed on the minion in the order they are defined on the command line, and then the data from all of the commands are returned in a dictionary. This means that the set of commands are called in a predictable way, and the returned data can be easily interpreted.
Executing compound commands if done by passing a comma delimited list of functions, followed by a comma delimited list of arguments:
salt '*' cmd.run,test.ping,test.echo 'cat /proc/cpuinfo',,foo
The trick to look out for here, is that if a function is being passed no
arguments, then there needs to be a placeholder for the absent arguments. This
is why in the above example, there are two commas right next to each other.
test.ping
takes no arguments, so we need to add another comma, otherwise
Salt would attempt to pass "foo" to test.ping
.
If you need to pass arguments that include commas, then make sure you add spaces around the commas that separate arguments. For example:
salt '*' cmd.run,test.ping,test.echo 'echo "1,2,3"' , , foo
You may change the arguments separator using the --args-separator
option:
salt --args-separator=:: '*' some.fun,test.echo params with , comma :: foo
Shell completion scripts for the Salt CLI are available in the pkg
Salt
source directory.