Using arrays of resources

Anything that you can do to a resource, you can do to an array of resources. Use this idea to refactor your manifests to make them shorter and clearer.

How to do it…

Here are the steps to refactor using arrays of resources:

1. Identify a class in your manifest where you have several instances of the same kind of resource, for example, packages:

     package { 'sudo' : ensure => installed }
     package { 'unzip' : ensure => installed }
     package { 'locate' : ensure => installed }
     package { 'lsof' : ensure => installed }
     package { 'cron' : ensure => installed }
     package { 'rubygems' : ensure => installed }

2. Group them together and replace them with a single package resource using an array:

     package
     {
       [ 'cron',
       'locate',
       'lsof',
       'rubygems',
       'sudo',
       'unzip' ]:
       ensure => installed,
     }

How it works…

Most of Puppet's resource types can accept an array instead of a single name, and will create one instance for each of the elements in the array. All the parameters you provide for the resource (for example, ensure => installed) will be assigned to each of the new resource instances. This shorthand will only work when all the resources have the same attributes.

See also

• The Iterating over multiple items recipe in Chapter 1, Puppet Language and Style