Book Image

Puppet 5 Cookbook - Fourth Edition

By : Thomas Uphill
Book Image

Puppet 5 Cookbook - Fourth Edition

By: Thomas Uphill

Overview of this book

Puppet is a configuration management system that automates all your IT configurations, giving you control of managing each node. Puppet 5 Cookbook will take you through Puppet's latest and most advanced features, including Docker containers, Hiera, and AWS Cloud Orchestration. Updated with the latest advancements and best practices, this book delves into various aspects of writing good Puppet code, which includes using Puppet community style, checking your manifests with puppet-lint, and learning community best practices with an emphasis on real-world implementation. You will learn to set up, install, and create your first manifests with version control, and also learn about various sysadmin tasks, including managing configuration files, using Augeas, and generating files from snippets and templates. As the book progresses, you'll explore virtual resources and use Puppet's resource scheduling and auditing features. In the concluding chapters, you'll walk through managing applications and writing your own resource types, providers, and external node classifiers. By the end of this book, you will have learned to report, log, and debug your system.
Table of Contents (16 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Using array iterations in templates


In the previous example, we saw that you can use Ruby to interpolate different values in templates depending on the result of an expression. But you're not limited to getting one value at a time. You can put lots of them in a Puppet array and then have the template generate some content for each element of the array using a loop.

How to do it...

Follow these steps to build an example of iterating over arrays:

  1. Modify your site.pp file as follows:
node 'cookbook' {
  $ipaddresses = ['192.168.0.1','158.43.128.1', '10.0.75.207' ]
  file { '/tmp/addresslist.txt':
    content => template('base/addresslist.erb')
  }
}
  1. Create a modules/base/templates/addresslist.erb file with the following contents:
<% @ipaddresses.each do |ip| -%>
IP address <%= ip %> is present
<% end -%>
  1. Update the code on your Puppet master and run puppet agent on the cookbook:
[root@cookbook ~]# puppet agent -t 
...
Info: Caching catalog for cookbook.example.com 
Info: Applying...