command_execution_once
Execute a command only once on a node.
⚙️ Compatible targets: Linux
Parameters
Name | Documentation |
---|---|
command | Command to run. This parameter is required. |
ok_codes | List of codes that produce a repaired status separated with commas (ex: 1,2,5). Defaults to 0. This parameter is optional. |
until | Try to execute the command until a particular state: 'ok', 'any' (defaults to 'any'). Choices:
This parameter is optional. |
unique_id | To identify the action without losing track if the command changes. Defaults to the command if you don't need it. This parameter is optional. |
Outcome conditions
You need to replace ${command}
with its actual canonified value.
- ✅ Ok:
command_execution_once_${command}_ok
- ☑️ Already compliant:
command_execution_once_${command}_kept
- 🟨 Repaired:
command_execution_once_${command}_repaired
- ☑️ Already compliant:
- ❌ Error:
command_execution_once_${command}_error
Example
method: command_execution_once
params:
ok_codes: OPTIONAL_VALUE
command: VALUE
until: any
unique_id: OPTIONAL_VALUE
Documentation
This method is useful for specific commands that should only be executed once per node.
If you can spot a condition for the command execution by testing the state of its target,
it is better to use the condition_from_command
method to test the state coupled with
the command_execution_result
method to run the command if necessary.
In case of reinstallation or factory-reset of the Rudder agent, this method will no longer detect if a command has already been executed.
The method will:
Define the command_execution_once_${command}_kept
condition and do nothing if
a command_execution_once
has already been executed on this machine with the same
Unique id.
Execute the command if it is the first occurrence and:
- If the parameter Until is
*any*
, it will consider the command as executed on the machine and define either:command_execution_once_${command}_repaired
if the return code is in ok_codes,command_execution_once_${command}_error
otherwise.
- If the parameter Until is ok and:
- If the return code is in the Ok codes list, define the
command_execution_once_${command}_repaired
condition - If the return code is not in Ok codes it define the
command_execution_once_${command}_error
condition and retry at next agent run.
- If the return code is in the Ok codes list, define the
If an exit code is not in the list it will lead to an error status. If you want "0" to be a success you have to list it in the Ok codes list
Example:
If you use:
command_execution_once("command -a -t", "0", "ok", "my_program_setup")
It will retry to run command -a -t
until it returns "0". Then it will
not execute it again.