Book Image

Mastering Ansible, 4th Edition - Fourth Edition

By : James Freeman, Jesse Keating
Book Image

Mastering Ansible, 4th Edition - Fourth Edition

By: James Freeman, Jesse Keating

Overview of this book

Ansible is a modern, YAML-based automation tool (built on top of Python, one of the world’s most popular programming languages) with a massive and ever-growing user base. Its popularity and Python underpinnings make it essential learning for all in the DevOps space. This fourth edition of Mastering Ansible provides complete coverage of Ansible automation, from the design and architecture of the tool and basic automation with playbooks to writing and debugging your own Python-based extensions. You'll learn how to build automation workflows with Ansible’s extensive built-in library of collections, modules, and plugins. You'll then look at extending the modules and plugins with Python-based code and even build your own collections — ultimately learning how to give back to the Ansible community. By the end of this Ansible book, you'll be confident in all aspects of Ansible automation, from the fundamentals of playbook design to getting under the hood and extending and adapting Ansible to solve new automation challenges.
Table of Contents (18 chapters)
Section 1: Ansible Overview and Fundamentals
Section 2: Writing and Troubleshooting Ansible Playbooks
Section 3: Orchestration with Ansible

Error recovery

While error conditions can be narrowly defined, there will be times when real errors happen. Ansible provides a method to react to true errors, a method that allows running additional tasks when an error occurs, defining specific tasks that always execute even if there was an error, or even both. This method is the block feature.

The blocks feature, introduced with Ansible version 2.0, provides some additional structure to related sets of play task. Blocks can group tasks together into a logical unit, which can have task controls applied to the unit (or block) as a whole. In addition, a block of tasks can have optional rescue and always sections, which execute on condition of an error and regardless of the error state, respectively. We will explore how these work in the following two sections.

Using the rescue section

The rescue section of a block defines a logical unit of tasks that will be executed...