Configuration management has become a requirement for system administrators. Knowing how to use configuration management tools, such as Puppet, enables administrators to take full advantage of automated provisioning systems and cloud resources. There is a natural progression from performing a task, scripting a task to creating a module in Puppet, or Puppetizing a task.
This book takes you beyond the basics and explores the full power of Puppet, showing you in detail how to tackle a variety of real-world problems and applications. At every step, it shows you exactly what commands you need to type and includes complete code samples for every recipe. It takes you from a rudimentary knowledge of Puppet to a more complete and expert understanding of Puppet's latest and most advanced features, community best practices, scaling, and performance. This edition of the book includes recipes for configuring and using Hiera, puppetdb and operating a centralized puppetmaster configuration.
This book also includes real examples from production systems and techniques that are in use in some of the world's largest Puppet installations. It will show you different ways to do things using Puppet, and point out some of the pros and cons of these approaches.
The book is structured so that you can dip in at any point and try out a recipe without having to work your way through from cover to cover. Whatever your level of Puppet experience, there's something for you—from simple workflow tips to advanced, high-performance Puppet architectures.
Puppet is an ever-changing ecosystem of tools. I've tried to include all the tools that I feel are important today, such as r10k. The #puppet IRC channel, puppetlabs blog (http://puppetlabs.com/blog), and the Forge (http://forge.puppetlabs.com) are great resources to stay up to date with the changes being made to Puppet.
Chapter 1, Puppet Language and Style, introduces the Puppet language and shows how to write manifests. The Puppet linting tool, puppet-lint, is introduced and we review best practices to write Puppet code. Metaparameters are shown with examples. We also preview proposed changes to the Puppet language by using the future parser.
Chapter 2, Puppet Infrastructure, is all about how to deploy Puppet in your environment. We cover the two main methods of installation, centralized and decentralized (masterless). We show you how to use Git to centrally manage your code. We also configure puppetdb and Hiera.
Chapter 3, Writing Better Manifests, deals with organizing your Puppet manifests. Manifests are used to build modules; we introduce the concept of roles and profiles to abstract how modules are applied to machines. Parameterized classes are introduced. We also show you how to efficiently define resources with arrays of resources and resource defaults.
Chapter 4, Working with Files and Packages, shows you how to manage files using snippets (fragments). We introduce the power of templating with both Ruby (ERB) and Puppet (EPP) templates. We also explore ways to secure information stored in your Puppet manifests.
Chapter 5, Users and Virtual Resources, deals with the advanced topic of virtual and exported resources. Virtual resources are a way of defining resources but not applying them by default. Exported resources are similar but are used to have resources from one machine, applied to one or more other machines.
Chapter 6, Managing Resources and Files, is about dealing with directories and purging resources not controlled by Puppet. We show you how to have file resources applied differently on different machines. Methods for managing host entries in /etc/hosts are shown with exported resources examples.
Chapter 7, Managing Applications, shows you how to use Puppet to manage your deployed applications. Using public Forge modules, we configure Apache, nginx, and MySQL.
Chapter 8, Internode Coordination, explores exported resources. We use exported resources to configure NFS, haproxy, and iptables.
Chapter 9, External Tools and the Puppet Ecosystem, shows you how to extend Puppet with your own types and providers, how to make your own facts, as well as some of the more advanced tools such as Puppet-librarian and r10k.
Chapter 10, Monitoring, Reporting, and Troubleshooting, is the final chapter where we show you how to leverage Puppet to see where the problems are in your infrastructure. Some of the more common problems are shown with solutions.
You will need a computer capable of running Linux Virtual Machines. The examples in the book use Debian and Enterprise Linux-based distributions. You will also need an Internet connection to utilize the repositories provided by puppetlabs.
This book assumes a familiarity with Linux administration. The examples require some experience with command-line usage and basic text file editing. Although beneficial, previous coding experience is not 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 concatenate arrays with the + operator or append them with the << operator."
A block of code is set as follows:
slice ($firewall_rules,2) |$ip, $port| {firewall {"$port from $ip": dport => $port, source => "$ip", action => 'accept', }
}Any command-line input or output is written as follows:
Notice: 1 Notice: 2 Notice: 3 Notice: 4 Notice: 5 # cp /usr/src/asterisk-addons/configs/cdr_mysql.conf.sample /etc/asterisk/cdr_mysql.conf
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: "In this graph it is easy to see that Package['ntp'] is the first resource to apply, then File['/etc/ntp.conf'] and finally Service['ntp']."
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