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
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Anatomy of a Puppet run, under the hood


We have seen the output of a Puppet run in Chapter 1, Puppet Essentials, now let's explore what happens behind those messages.

We can identify four main stages that turn our Puppet code in a catalog that is applied on clients:

  • Parsing and compiling: This is where Puppet manifests are fed to the Puppet::Parser class, which does basic syntax checks and produce an Abstract Syntax Tree (AST) object. This represents the same objects we defined in our manifests in a machine-friendly format. Both the facts, received from the client, and the AST are passed to the compiler. Facts and manifests are interpreted and the result converted into a tree of transportable objects: the resource catalog, commonly called catalog. This phase happens on the server unless we use the puppet apply command.

  • Transport: In this phase, the Master serializes the catalog in the PSON format (a Puppet version of JSON), and sends it over HTTPS to the client. Here, it is deserialized and...