Book Image

Puppet 5 Cookbook - Fourth Edition

By : Thomas Uphill
Book Image

Puppet 5 Cookbook - Fourth Edition

By: Thomas Uphill

Overview of this book

Puppet is a configuration management system that automates all your IT configurations, giving you control of managing each node. Puppet 5 Cookbook will take you through Puppet's latest and most advanced features, including Docker containers, Hiera, and AWS Cloud Orchestration. Updated with the latest advancements and best practices, this book delves into various aspects of writing good Puppet code, which includes using Puppet community style, checking your manifests with puppet-lint, and learning community best practices with an emphasis on real-world implementation. You will learn to set up, install, and create your first manifests with version control, and also learn about various sysadmin tasks, including managing configuration files, using Augeas, and generating files from snippets and templates. As the book progresses, you'll explore virtual resources and use Puppet's resource scheduling and auditing features. In the concluding chapters, you'll walk through managing applications and writing your own resource types, providers, and external node classifiers. By the end of this book, you will have learned to report, log, and debug your system.
Table of Contents (16 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Using tags


Sometimes one Puppet class needs to know about another, or at least know whether or not it's present. For example, a class that manages the firewall may need to know whether or not the node is a web server.

Puppet's tagged function will tell you whether a named class or resource is present in the catalog for this node. You can also apply arbitrary tags to a node or class and check for the presence of these tags. Tags are another metaparameter, similar to require and notify, which we introduced in Chapter 1, Puppet Language and Style. Metaparameters are used in the compilation of the Puppet catalog but are not attributes of the resource to which they are attached.

How to do it...

To help you find out whether you're running on a particular node or class of nodes, all nodes are automatically tagged with the node name and the names of any classes they include. Here's an example that shows you how to use tagged to get this information:

  1. Add the following code to your site.pp file (replacing...