You'll find the following chapters in this book:

Chapter 1, Puppet Infrastructure, shows how to set up Puppet for the first time, including instructions on installing Puppet, creating your first manifests, using version control with Puppet, building a distributed Puppet architecture based on Git, writing a script to apply Puppet manifests, running Puppet automatically, using Rake to bootstrap machines and deploy changes, and using Git hooks to automatically syntax-check your manifests.

Chapter 2, Puppet Language and Style, covers aspects of writing good Puppet code, including using Puppet community style, checking your manifests with puppet-lint, structuring your manifests with modules, using standard naming and style conventions, using inline templates, using iteration, conditional statements, and regular expressions, using selectors and case statements, and string operations.

Chapter 3, Writing Better Manifests, goes into detail on specific features of Puppet that you can use to improve your code quality and usability, including arrays, definitions, ordering your resources with dependencies, inheriting from nodes and classes, passing parameters to classes, overriding parameters, reading information from the environment, writing reusable manifests, and using tags and run stages.

Chapter 4, Working with Files and Packages, deals with some of the most common sysadmin tasks, including managing config files, using Augeas, generating files from snippets and templates, managing third-party package repositories, using GnuPG to encrypt secret data in Puppet, and building packages from source.

Chapter 5, Users and Virtual Resources, explains what virtual resources are and how they can help you manage different combinations of users and packages on different machines, and shows you how to use Puppet's resource scheduling and auditing features.

Chapter 6, Applications, focuses on some specific applications that you may need to manage with Puppet, including complete recipes for Apache and Nginx, MySQL, and Ruby.

Chapter 7, Servers and Cloud Infrastructure, extends the power of Puppet to manage virtual machines, both on the cloud and on your desktop, with recipes for Vagrant and EC2 instances. It also shows you how to set up load balancing with HAProxy, firewalls with iptables, network filesystems with NFS, and high-availability services with Heartbeat.

Chapter 8, External Tools and the Puppet Ecosystem, looks at some of the tools that have grown up around Puppet, including Hiera, Facter, and rspec-puppet. It also introduces you to some advanced topics including writing your own resource types, providers, and external node classifiers.

Chapter 9, Monitoring, Reporting, and Troubleshooting, covers ways that Puppet can report information about what it's doing, and the status of your system. This includes reports, log, and debug messages, dependency graphing, testing and dry-running your manifests, and a guide to some of Puppet's more common error messages.

To run the examples in this book, you will need a computer with Ubuntu Linux 12.04 and an Internet connection.

The book assumes that the reader has a little experience of Linux systems administration, including familiarity with the command line, file system, and text editing. No programming experience is required.

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "You can check your manifests for style guide compliance using the puppet-lint tool."

A block of code is set as follows:

node 'cookbook' {
  cron { 'randomised cron job':
    command => '/bin/echo Hello, world >>/tmp/hello.txt',
    hour    => '*',
    minute  => random_minute(),
  }
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

newparam(:path) do
  validate do |value|
    basepath = File.dirname(value)
    unless File.directory?(basepath)
      raise ArgumentError , "The path %s doesn't exist" % basepath
    end
  end
end

Any command-line input or output is written as follows:

ubuntu@cookbook:~/puppet$ papply
Notice: Hello, I was included by your ENC!
Notice: /Stage[main]/Admin::Helloenc/Notify[Hello, I was included by your ENC!]/message: defined 'message' as 'Hello, I was included by your ENC!'
Notice: Finished catalog run in 0.29 seconds

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "clicking the Next button moves you to the next screen".

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