Book Image

Mastering Ansible, Second Edition - Second Edition

By : Jesse Keating
Book Image

Mastering Ansible, Second Edition - Second Edition

By: Jesse Keating

Overview of this book

This book provides you with the knowledge you need to understand how Ansible 2.1 works at a fundamental level and leverage its advanced capabilities. You'll learn how to encrypt Ansible content at rest and decrypt data at runtime. You will master the advanced features and capabilities required to tackle the complex automation challenges of today and beyond. You will gain detailed knowledge of Ansible workflows, explore use cases for advanced features, craft well thought out orchestrations, troubleshoot unexpected behaviour, and extend Ansible through customizations. Finally, you will discover the methods used to examine and debug Ansible operations, helping you to understand and resolve issues. By the end of the book, the readers will be able to unlock the true power of the Ansible automation engine and will tackle complex real world actions with ease.
Table of Contents (16 chapters)
Mastering Ansible - Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Defining a change


Similar to defining a task failure, it is also possible to define what constitutes a changed task result. This capability is particularly useful with the command family of modules (command, shell, raw, and script). Unlike most other modules, the modules of this family do not have an inherent idea of what a change may be. In fact, unless otherwise directed, these modules only result in failed, changed, or skipped. There is simply no way for these modules to assume a changed condition versus unchanged.

The changed_when condition allows a playbook author to instruct a module how to interpret a change. Just like failed_when, changed_when performs a test to generate a Boolean result. Frequently, the tasks used with changed_when are commands that will exit nonzero to indicate that no work is needed to be done, so often authors will combine changed_when and failed_when to fine-tune the task result evaluation. In our previous example, the failed_when condition caught the case where...