Managing Infrastructure with Puppet

Chapter 2. Puppeteering

Before we can get into a full-scale example, we need to add more tools to our Puppet workbench. Puppet provides several layers of abstraction to give you a variety of options for structuring configurations.

Defines

In this example, I’ve defined a type called yellifmissing, which takes a parameter $path. Then I can instantiate an instance of yellifmissing called pathnumber1 and pass the path parameter /tmp/filenumber1. Then I can do it again. Each of these resource declarations will email me about the specified missing file. Using a defined type, I can compartmentalize and duplicate blocks of logic, similar to an instance class in most object-oriented languages:

define yellifmissing ($path) {
    exec { mailaboutit:
            command => "echo 'OhNoes!' | mail -s '$name is missing' [e-mail]",
            unless => "test -f $path",
            }
    }

yellifmissing { pathnumber1: path => '/tmp/filenumber1' }
yellifmissing { pathnumber2: path => '/tmp/filenumber2' }