Book Image

Mastering Puppet 5

By : Ryan Russell-Yates, Jason Southgate
Book Image

Mastering Puppet 5

By: Ryan Russell-Yates, Jason Southgate

Overview of this book

Puppet is a configuration management system and a language written for and by system administrators to manage a large number of systems efficiently and prevent configuration drift. The core topics this book addresses are Puppet's latest features and mastering Puppet Enterprise. You will begin by writing a new Puppet module, gaining an understanding of the guidelines and style of the Puppet community. Following on from this, you will take advantage of the roles and profiles pattern, and you will learn how to structure your code. Next, you will learn how to extend Puppet and write custom facts, functions, types, and providers in Ruby, and also use the new features of Hiera 5. You will also learn how to configure the new Code Manager component, and how to ensure code is automatically deployed to (multiple) Puppet servers. Next, you will learn how to integrate Puppet with Jenkins and Git to build an effective workflow for multiple teams, and use the new Puppet Tasks feature and the latest Puppet Orchestrator language extensions. Finally, you will learn how to scale and troubleshoot Puppet. By the end of the book, you will be able to deal with problems of scale and exceptions in your code, automate workflows, and support multiple developers working simultaneously.
Table of Contents (19 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
Index

Introducing a frame for the environment


Here's a typical scenario for Hiera: you find yourself having to override the DNS setting for your development environment because that environment can't connect to the production resolver on your network. You then deploy your production in a second data center, and you need that location to be different. Hiera allows us to model settings such as the production DNS resolver is10.20.1.3, and the development DNS server is10.199.30.2.

 

 

To accommodate this type of scenario, we can introduce what's best described as an environment frame within the Hiera hierarchy, as follows:

---
version: 5
 hierarchy:
   - name: "Per-node data"
     path: "nodes/%{trusted.certname}.yaml"

   - name: "Per-environment data"
     path: "%{server_facts.environment}.yaml"

 - name: Common
     path: common.yaml

The percent-braces %{variable} syntax denotes a Hiera interpolation token. Wherever you use these interpolation tokens, Hiera will evaluate the variable's value and inserts...