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

Accessing data bag values from external scripts


Sometimes, you cannot put a server under full Chef control (yet). In such cases, you might want to be able to access the values managed in Chef data bags from scripts that are not maintained by Chef. The easiest way to do this is to dump the data bag values (or any node values for that matter) into a JSON file and let your external script read them from there.

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.

Create a data bag item, as shown in the following steps, so that we can use its values later:

  1. Create the data bag:

    mma@laptop:~/chef-repo $ mkdir data_bags/servers
    mma@laptop:~/chef-repo $ knife data bag create servers
    Created data_bag[servers]
    
  2. Create the first data bag item:

    mma@laptop:~/chef-repo $ subl data_bags/servers/backup.json
    {
      "id": "backup",
      "host": "10.0.0.12"
    }
    mma...