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

Data manipulation

While control structures influence the flow of template processing, another tool exists that can help you to modify the contents of a variable. This tool is called a filter. Filters are the same as small functions, or methods, that can be run on the variable. Some filters operate without arguments, some take optional arguments, and some require arguments. Filters can be chained together as well, where the result of one filter action is fed into the next filter and then the next. Jinja2 comes with many built-in filters, and Ansible extends these with many custom filters that are available to you when using Jinja2 within templates, tasks, or any other place Ansible allows templating.


A filter is applied to a variable by way of the pipe symbol, |, followed by the name of the filter, and then any arguments for the filter inside parentheses. There can be a space between the variable name and the pipe symbol, as well as a space...