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

Importing dynamic information


Even though some system administrators like to wall themselves off from the rest of the office using piles of old printers, we all need to exchange information with other departments from time to time. For example, you may want to insert data into your Puppet manifests which is derived from some outside source. The generate function is ideal for this.

Getting ready

Follow these steps to prepare for running the example.

  1. Create the script /usr/local/bin/message.rb with the following contents:

    #!/usr/bin/env ruby
    
    puts "Hi, I'm Ruby! Will you play with me?"
  2. Make the script executable:

    ubuntu@cookbook:~/puppet$ sudo chmod a+x /usr/local/bin/message.rb
    

How to do it…

This example calls the external script we created previously and gets its output.

  1. Add the following to your manifest:

    $message = generate('/usr/local/bin/message.rb')
    notify { $message: }
  2. Run Puppet:

    ubuntu@cookbook:~/puppet$ papply
    Notice: Hi, I'm Ruby! Will you play with me?
    

How it works…

The generate function...