Book Image

Extending Puppet - Second Edition

By : Alessandro Franceschi, Jaime Soriano Pastor
Book Image

Extending Puppet - Second Edition

By: Alessandro Franceschi, Jaime Soriano Pastor

Overview of this book

Puppet has changed the way we manage our systems, but Puppet itself is changing and evolving, and so are the ways we are using it. To tackle our IT infrastructure challenges and avoid common errors when designing our architectures, an up-to-date, practical, and focused view of the current and future Puppet evolution is what we need. With Puppet, you define the state of your IT infrastructure, and it automatically enforces the desired state. This book will be your guide to designing and deploying your Puppet architecture. It will help you utilize Puppet to manage your IT infrastructure. Get to grips with Hiera and learn how to install and configure it, before learning best practices for writing reusable and maintainable code. You will also be able to explore the latest features of Puppet 4, before executing, testing, and deploying Puppet across your systems. As you progress, Extending Puppet takes you through higher abstraction modules, along with tips for effective code workflow management. Finally, you will learn how to develop plugins for Puppet - as well as some useful techniques that can help you to avoid common errors and overcome everyday challenges.
Table of Contents (19 chapters)
Extending Puppet Second Edition
About the Authors
About the Reviewer

Using Hiera as an ENC

Hiera provides an interesting function called hiera_include, which allows you to include all the classes defined for a given key.

This, in practice, exploits the Hiera flexibility to provide classes to nodes as does an External Node Classifier.

It's enough to place in our /etc/puppet/manifests/site.pp a line like this:


Then, define in our data sources a classes key with an array of the classes to include.

In a YAML-based backend, it would look like the following:

  - apache
  - mysql
  - php

This is exactly the same as having something like the following in our site.pp:

include apache
include mysql
include php

The classes key (it can have any name, but classes is a standard de facto) contains an array, which is merged along the hierarchy. So, in common.yaml, we can define the classes that we want to include on all our nodes, and include specific classes for specific servers, adding them at the different layers of our hierarchy.

Along with...