Book Image

Chef Cookbook - Third Edition

By : Matthias Marschall
Book Image

Chef Cookbook - Third Edition

By: Matthias Marschall

Overview of this book

Chef is a configuration management tool that lets you automate your more cumbersome IT infrastructure processes and control a large network of computers (and virtual machines) from one master server. This book will help you solve everyday problems with your IT infrastructure with Chef. It will start with recipes that show you how to effectively manage your infrastructure and solve problems with users, applications, and automation. You will then come across a new testing framework, InSpec, to test any node in your infrastructure. Further on, you will learn to customize plugins and write cross-platform cookbooks depending on the platform. You will also install packages from a third-party repository and learn how to manage users and applications. Toward the end, you will build high-availability services and explore what Habitat is and how you can implement it.
Table of Contents (15 chapters)
Chef Cookbook - Third Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Using libraries


You can use arbitrary Ruby code within your recipes. If your logic isn't too complicated, it's totally fine to keep it inside your recipe. However, as soon as you start using plain Ruby more than Chef DSL, it's time to the move the logic into external libraries.

Libraries provide a place to encapsulate Ruby code so that your recipes stay clean and neat. In this section, we'll create a simple library to see how this works.

Getting ready

Make sure you have a cookbook called my_cookbook and that the run_list of your node includes my_cookbook, as described in the Creating and using cookbooks recipe of Chapter 1, Chef Infrastructure.

How to do it...

Let's create a library and use it in a cookbook:

  1. Create a helper method in your own cookbook's library:

    mma@laptop:~/chef-repo $ mkdir -p cookbooks/my_cookbook/libraries
    mma@laptop:~/chef-repo $ subl cookbooks/my_cookbook/libraries/ipaddress.rb
    class Chef::Recipe
      def netmask(ipaddress)
        IPAddress(ipaddress).netmask
      end
    end
    
  2. Use your...