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

Passing parameters from Hiera


Like the parameter defaults we introduced in the previous chapter Puppet Infrastructure , Hiera may be used to provide default values to classes. Automatic parameter lookup via Hiera has been on by default since version 3 of Puppet.

Getting ready

Configure hiera as we did in Chapter 2, Puppet Infrastructure. Create a global or common YAML file; this will serve as the default for all values.

How to do it...

  1. We'll create a class with parameters and no default values. Create the directory modules/mysql/manifests and then create modules/mysql/manifests/init.pp with the following content:
class mysql (
  Integer $port,
  String $socket,
  Variant[String,Array[String]] $package
  ) {
    notify {"Port: ${port} Socket: ${socket} Package: ${package}": }
}
  1. Update your common.yaml file in Hiera with the default values for the mysql class:
---
mysql::port: 3306
mysql::package: 'mysql-server'
mysql::socket: '/var/lib/mysql/mysql.sock'
  1. Apply the class to a node; you can add the...