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)
1
Section 1: Ansible Overview and Fundamentals
7
Section 2: Writing and Troubleshooting Ansible Playbooks
13
Section 3: Orchestration with Ansible

Chapter 6: Unlocking the Power of Jinja2 Templates

Manipulating configuration files by hand is a tedious and error-prone task. Equally, performing pattern matching to make changes to existing files is risky, and ensuring that the patterns are reliable and accurate can be time-consuming. Whether you are using Ansible to define configuration file content, perform variable substitution in tasks, evaluate conditional statements, or beyond, templating comes into play with nearly every Ansible playbook. In fact, given the importance of this task, it could be said that templating is the lifeblood of Ansible.

The templating engine employed by Ansible is Jinja2, which is a modern and designer-friendly templating language for Python. Jinja2 deserves its own book; however, in this chapter, we will cover some of the more common usage patterns of Jinja2 templating in Ansible to demonstrate the power it can bring to your playbooks. In this chapter, we will cover the following topics...