Book Image

Puppet 3 Cookbook - Second Edition

By : John Arundel
Book Image

Puppet 3 Cookbook - Second Edition

By: John Arundel

Overview of this book

A revolution is happening in web operations. Configuration management tools can build servers in seconds, and automate your entire network. Tools like Puppet are essential to taking full advantage of the power of cloud computing, and building reliable, scalable, secure, high-performance systems. More and more systems administration and IT jobs require some knowledge of configuration management, and specifically Puppet."Puppet 3 Cookbook" takes you beyond the basics to explore 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 full code samples for every recipe.The book takes the reader from a basic knowledge of Puppet to a complete and expert understanding of Puppet's latest and most advanced features, community best practices, writing great manifests, scaling and performance, and extending Puppet by adding your own providers and resources. It starts with guidance on how to set up and expand your Puppet infrastructure, then progresses through detailed information on the language and features, external tools, reporting, monitoring, and troubleshooting, and concludes with many specific recipes for managing popular applications.The book includes real examples from production systems and techniques that are in use in some of the world's largest Puppet installations, including a distributed Puppet architecture based on the Git version control system. You'll be introduced to powerful tools that work with Puppet such as Hiera. The book also explains managing Ruby applications and MySQL databases, building web servers, load balancers, high-availability systems with Heartbeat, and many other state-of-the-art techniques
Table of Contents (16 chapters)
Puppet 3 Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Using run stages


A common requirement is to apply a certain group of resources before other groups (for example, installing a package repository or a custom Ruby version), or after others (for example, deploying an application once its dependencies are installed). Puppet's run stages feature allows you to do this.

By default, all resources in your manifest are applied in a single stage named main. If you need a resource to be applied before all others, you can assign it to a new run stage that is specified to come before main. Similarly, you could define a run stage that comes after main. In fact, you can define as many run stages as you need and tell Puppet which order they should be applied in.

In this example, we'll use stages to ensure one class is applied first and another last.

How to do it…

Here are the steps to create an example of using run stages:

  1. Create the file modules/admin/manifests/stages.pp with the following contents:

    class admin::stages {
      stage { 'first': before => Stage...