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 Augeas to reliably edit config files


Sometimes it seems like every application has its own subtly different config file format, and writing regular expressions to parse and modify all of them can be a tiresome business.

Thankfully, Augeas is here to help. Augeas is a system that aims to simplify working with different config file formats by presenting them all as a simple tree of values. Puppet's Augeas support allows you to create augeas resources that can make the required config changes intelligently and automatically.

How to do it...

Follow these steps to create an example Augeas resource:

  1. Modify your base module as follows:
class base {
  augeas { 'enable-ip-forwarding':
    incl    => '/etc/sysctl.conf',
    lens    => 'Sysctl.lns',
    changes => ['set net.ipv4.ip_forward 1'],
  }
}
  1. Run Puppet:
[root@cookbook ~]# puppet agent -t
Info: Using configured environment 'production'
Info: Retrieving pluginfacts
Info: Retrieving plugin
Info: Caching catalog for cookbook.example.com...