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 why-run mode to find out what a recipe might do


why-run mode lets each resource tell you what it would do during a Chef client run, assuming certain prerequisites. This is great because it gives you a glimpse of what might really happen on your node when you run your recipe for real.

However, because Chef converges a lot of resources to a desired state, why-run will never be accurate for a complete run. Nevertheless, it might help you during development while you're adding resources step-by-step to build the final recipe.

In this section, we'll try out why-run mode to see what it tells us about our Chef client runs.

Getting ready

To try out why-run mode, you need a node where you can execute the Chef client and at least one cookbook available on that node.

How to do it…

Let's try to run the ntp cookbook in why-run mode:

  1. Override the current run list to run the ntp recipe in why-run mode on a brand new box:

    user@server:~$ sudo chef-client -o 'recipe[ntp]' --why-run
    ...TRUNCATED OUTPUT......