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 regular expression substitutions


Puppet's regsubst function provides an easy way to manipulate text, search and replace within strings, or extract patterns from strings. We often need to do this with data obtained from a fact, for example, or from external programs.

In this example, we'll see how to use regsubst to extract the first three octets of an IPv4 address (the network part, assuming it's a class C address).

How to do it…

Follow these steps to build the example:

  1. Add the following code to your manifest:

    $class_c = regsubst($::ipaddress, '(.*)\..*', '\1.0')
    notify { "The network part of ${::ipaddress} is
      ${class_c}": }
  2. Run Puppet:

    ubuntu@cookbook:~/puppet$ papply
    Notice: The network part of 10.96.247.132 is 10.96.247.0
    Notice: /Stage[main]/Admin::Test/Notify[The network part of 10.96.247.132 is 10.96.247.0]/message: defined 'message' as 'The 
    etwork part of 10.96.247.132 is 10.96.247.0'
    Notice: Finished catalog run in 0.09 seconds
    

How it works…

regsubst takes at least three parameters...