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

Overriding attributes


You can set attribute values in attribute files. Usually, cookbooks come with reasonable default values for attributes. However, the default values might not suit your needs. If they don't fit, you can override attribute values.

In this section, we'll look at how to override attributes from within recipes and roles.

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 in Chapter 1, Chef Infrastructure.

How to do it…

Let's see how we can override attribute values:

  1. Edit the default attributes file to add an attribute:

    mma@laptop:~/chef-repo $ subl   cookbooks/my_cookbook/attributes/default.rb
    default['my_cookbook']['version'] = '1.2.3'
    
  2. Edit your default recipe. You'll override the value of the version attribute and print it to the console:

    mma@laptop:~/chef-repo $ subl   cookbooks/my_cookbook/recipes/default.rb
    node.override['my_cookbook']['version'] ...