Book Image

Puppet 4.10 Beginner's Guide - Second Edition

By : John Arundel
Book Image

Puppet 4.10 Beginner's Guide - Second Edition

By: John Arundel

Overview of this book

Puppet 4.10 Beginner’s Guide, Second Edition, gets you up and running with the very latest features of Puppet 4.10, including Docker containers, Hiera data, and Amazon AWS cloud orchestration. Go from beginner to confident Puppet user with a series of clear, practical examples to help you manage every aspect of your server setup. Whether you’re a developer, a system administrator, or you are simply curious about Puppet, you’ll learn Puppet skills that you can put into practice right away. With practical steps giving you the key concepts you need, this book teaches you how to install packages and config files, create users, set up scheduled jobs, provision cloud instances, build containers, and so much more. Every example in this book deals with something real and practical that you’re likely to need in your work, and you’ll see the complete Puppet code that makes it happen, along with step-by-step instructions for what to type and what output you’ll see. All the examples are available in a GitHub repo for you to download and adapt for your own server setup.
Table of Contents (20 chapters)
Puppet 4.10 Beginner's Guide Second Edition
About the Author
About the Reviewer
Customer Feedback

Introducing variables

A variable in Puppet is simply a way of giving a name to a particular value, which we can then use wherever we would use the literal value (variable_string.pp):

$php_package = 'php7.0-cli'

package { $php_package:
  ensure => installed,

The dollar sign ($) tells Puppet that what follows is a variable name. Variable names must begin with a lowercase letter or an underscore, though the rest of the name can contain uppercase letters or numbers as well.

A variable can contain different types of data—one such type is a String (like php7.0-cli), but Puppet variables can also contain Number values, or Boolean values (true or false). Here are a few examples (variable_simple.pp):

$my_name = 'Zaphod Beeblebrox'
$answer = 42
$scheduled_for_demolition = true

Using Booleans

Strings and numbers are straightforward, but Puppet also has a special data type to represent true or false values, which we call Boolean values, after the logician George Boole. We have already encountered some...