Using inline templates

Templates are a powerful way of using embedded Ruby to help build config files dynamically and iterate over arrays, for example. But you can embed Ruby in your manifests directly without having to use a separate file by calling the inline_template function.

How to do it…

Here's an example of using inline_template:

Pass your Ruby code to inline_template within the Puppet manifest, as follows:

cron { 'chkrootkit':
  command => '/usr/sbin/chkrootkit >
    /var/log/chkrootkit.log 2>&1',
  hour    => inline_template('<%= @hostname.sum % 24 %>'),
  minute  => '00',
}

How it works…

Anything inside the string passed to inline_template is executed as if it were an ERB template. That is, anything inside <%= and %> delimiters will be executed as Ruby code, and the rest will be treated as a string.

In this example, we use inline_template to compute a different hour for this cron resource (a scheduled job) for each machine, so that the same job does not...