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

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, you can pass in the version number as a parameter.

How to do it...

In this example, we'll create a definition that accepts parameters:

  1. Declare the parameter as a part of the class definition:
class eventmachine(
  String $version
  ) {
  package { 'eventmachine':
    provider => gem,
    ensure   => $version,
  }
}
  1. Use the following syntax to include the class on a node:
class { 'eventmachine':
  version => '1.0.3',
}

How it works...

The class definition class eventmachine ($version) { is just like a normal class definition except it specifies that the class takes one parameter: $version. Inside the class, we've defined a package resource:

package { 'eventmachine':
  provider => gem,
  ensure   => $version,
}

This is a gem package...