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how to run puppet based on command output

asked 2015-10-28 11:12:22 -0600

johntest gravatar image


I am looking for a way to do the following

Based on the output of a command, need to decide if I want to run the manifest.

I do not want to run the manifest when "cat /var/tmp/check.txt" contains NULL (among other things). I do want to run the manifest when "cat /var/tmp/check.txt" does not contain NULL (among other things).

Seems like its a matter of simply using grep but how to do it with Puppet?


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Do you intend to run the manifest or just the resource? e.g. exec If you only need to run the run the `exec` resource for example, you can use the conditional `unless or only_if` parameter of that resource.

lupin gravatar imagelupin ( 2015-10-28 12:08:12 -0600 )edit

@lupin The whole manifest (multiple resources) is dependent upon whether this condition meets or not. Thanks

johntest gravatar imagejohntest ( 2015-10-28 12:37:01 -0600 )edit

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answered 2015-10-30 14:01:44 -0600

JohnsonEarls gravatar image

You can try doing this by creating a new stage that runs before the main stage, and have that stage do the test.

Note, your mileage may vary - I have not tried this outside of a very quick test.

The following example code, placed in your site.pp file, should only run the rest of the manifest if the file /var/tmp/check.txt is not empty.

stage { 'should_I_run':
    before => Stage['main']

class should_I_run {
    exec { "should_I_run":
        command => '/bin/test -s /var/tmp/check.txt' ,

class { 'should_I_run':
    stage => 'should_I_run' ,
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answered 2015-10-28 13:54:42 -0600

lavaman gravatar image

The way to get puppet to "respond" to the state of the system is using facter facts. You can create custom facts for whatever you want:

You would then decide whether to apply a class based on the fact value the same way you would with any fact:

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Asked: 2015-10-28 11:12:22 -0600

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Last updated: Oct 30 '15