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

Chapter 2. Managing Puppet Data with Hiera

The history of Puppet is an interesting example of how best practices have evolved with time, following new usage patterns and contributions from the community.

Once people started to write manifests with Puppet's DSL and express the desired state of their systems, they found themselves placing custom variables and parameters that expressed various resources of their infrastructures (IP addresses, hostnames, paths, URLs, names, properties, lists of objects, and so on) inside the code used to create the needed resource types.

At times, variables were used to classify and categorize nodes (systems' roles, operational environments, and so on), other times facts (such as $::operatingsystem) were used to provide resources with the right names and paths according to the underlying OS.

Variables could be defined in different places; they could be set via an External Node Classifier (ENC), inside node declarations or inside classes.

There was not (and actually...