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

Getting information about the environment


Sometimes, your recipes need to know details about the environment they are modifying. I'm not talking about Chef environments but about things such as Linux kernel versions, existing users, and network interfaces.

Chef provides all this information via the node object. Let's look at how to retrieve it.

Getting ready

Log in to any of your Chef-managed nodes and start chef-shell:

user@server:~$ sudo chef-shell --client
chef (12.16.42)>

How to do it…

Let's play around with the node object and look at what information it stores:

  1. List which information is available. The example shows the keys available on a Vagrant VM. Depending on what kind of server you work on, you'll find different data, as shown in the following:

    chef > node.keys.sort
    => ["block_device", "chef_packages", "command", "counters", "cpu", "current_user", "dmi", "domain", "etc", "filesystem", "fqdn", "hostname", "idletime", "idletime_seconds", "ip6address", "ipaddress", "kernel",...