Puppet 2.7 Cookbook

Passing parameters to classes

Sometimes it's very useful to parameterize some aspect of a class. For example, you might need to manage different versions of a gem package, and rather than making separate classes for each that differ only in the version number, or using inheritance and overrides, you can pass in the version number as a parameter.

How to do it…

1. Declare the parameter as part of the class definition as follows:

   class eventmachine( $version ) {
       package { "eventmachine":
           provider => gem,
           ensure   => $version,
       }
   }

2. Then use the following syntax to include the class on a node:

   class { "eventmachine": version => "0.12.8" }

How it works…

The class definition:

class eventmachine( $version ) {

is just like a normal class definition except it specifies ...