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 the in operator


The in operator tests whether one string contains another. Here's an example:

if 'spring' in 'springfield'

The preceding expression is true if the string spring is a substring of springfield, which it is. The in operator can also test for membership of arrays as follows:

if $crewmember in ['Frank', 'Dave', 'HAL' ]

When in is used with a hash, it tests whether the string is a key of the hash:

$interfaces = { 'lo' => '127.0.0.1', 
                'eth0' => '192.168.0.1' }
if 'eth0' in $interfaces {
  notify { "eth0 has address ${interfaces['eth0']}": }
}

How to do it…

The following steps will show you how to use the in operator:

  1. Add the following code to your manifest:

    if $::operatingsystem in [ 'Ubuntu', 'Debian' ] {
      notify { 'Debian-type operating system detected': }
    } elsif $::operatingsystem in [ 'RedHat', 'Fedora', 'SuSE', 'CentOS' ] {
      notify { 'RedHat-type operating system detected': }
    } else {
      notify { 'Some other operating system detected': }
    }
  2. Run Puppet:

    ubuntu...