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

Creating custom facts


While Facter's built-in facts are useful, it's actually quite easy to add your own facts. For example, if you have machines in different data centers or hosting providers, you could add a custom fact for this so that Puppet can determine if any local settings need to be applied (for example, local DNS servers or network routes).

How to do it…

Here's an example of a simple custom fact:

  1. Run the following command:

    ubuntu@cookbook:~/puppet$ mkdir -p modules/facts/lib/facter
    
  2. Create the file modules/facts/lib/facter/hello.rb with the following contents:

    Facter.add(:hello) do
      setcode do
        "Hello, world"
      end
    end
  3. Modify your manifests/nodes.pp file as follows:

    node 'cookbook' {
      notify { $::hello: }
    }
  4. Run Puppet:

    ubuntu@cookbook:~/puppet$ papply
    Notice: Hello, world
    Notice: /Stage[main]//Node[cookbook]/Notify[Hello, world]/message: defined 'message' as 'Hello, world'
    Notice: Finished catalog run in 0.24 seconds
    

How it works...

The built-in facts in Facter are defined in the same...