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

Expanding and contracting

An alternative to the in-place upgrade strategy is the expand and contract strategy. This strategy has become popular of late, thanks to the self-service nature of on-demand infrastructures, such as cloud computing or virtualization pools. The ability to create new servers on-demand from a large pool of available resources means that every deployment of an application can happen on brand new systems. This strategy avoids a host of issues, such as a buildup of cruft on long-running systems, such as the following:

  • Configuration files that are no longer managed by Ansible being left behind
  • Runaway processes consuming resources in the background
  • Changes being made to the server manually by human beings without updating the Ansible playbooks

Starting fresh each time also removes the differences between initial deployment and an upgrade. The same code path can be used, reducing the risk of surprises when upgrading an application...