Welcome to Mastering Ansible, your guide to a variety of advanced features and functionalities provided by Ansible, the automation and orchestration tool. This book will provide readers with the knowledge and skills to truly understand how Ansible functions at a fundamental level. This will allow readers to master the advanced capabilities needed to tackle complex automation challenges of today and the future. Readers will gain knowledge of Ansible workflows, explore use cases for advanced features, troubleshoot unexpected behavior, and extend Ansible through customization.
Chapter 1, System Architecture and Design of Ansible, looks at the ins and outs of how Ansible goes about performing tasks on behalf of an engineer, how it is designed, and how to work with inventory and variables.
Chapter 2, Protecting Your Secrets with Ansible, explores the tools available to encrypt data at rest and prevent secrets from being revealed at runtime.
Chapter 3, Unlocking the Power of Jinja2 Templates, states the varied uses of the Jinja2 templating engine within Ansible and discusses ways to make the most out of its capabilities.
Chapter 4, Controlling Task Conditions, describes the changing of the default behavior of Ansible to customize task error and change conditions.
Chapter 5, Composing Reusable Ansible Content with Roles, covers the approach to move beyond executing loosely-organized tasks on hosts to encapsulating clean and reusable abstractions to apply a specific functionality of a target set of hosts.
Chapter 6, Minimizing Downtime with Rolling Deployments, explains the common deployment and upgrade strategies to showcase relevant Ansible features.
Chapter 7, Troubleshooting Ansible, takes you through the various methods that can be employed to examine, introspect, modify, and debug the operations of Ansible.
Chapter 8, Extending Ansible, discovers the various ways in which new capabilities can be added to Ansible via modules, plugins, and inventory sources.
Chapter 9, Infrastructure Provisioning, will be working with cloud infrastructure providers and container systems to create an infrastructure to manage.
To follow the examples provided in this book, you will need access to a computer platform capable of running Ansible. Currently, Ansible can be run on any machine with Python 2.6 or 2.7 installed (Windows isn't supported for the control machine). This includes Red Hat, Debian, CentOS, OS X, any of the BSDs, and so on.
This book uses the Ansible 2.2.x.x series release.
Ansible installation instructions can be found at http://docs.ansible.com/ansible/intro_installation.html.
Some examples use Docker, version 1.12.6. Docker installation instructions can be found at: http://www.docker.com/community-edition.
This book is for Ansible developers and operators who have an understanding of the core elements and applications but are now looking to enhance their skills in applying automation using Ansible.
In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.
Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "We'll make use of this in a failed_when statement."
A block of code is set as follows:
- name: query sessions command: /sbin/iscsiadm –m session register: sessions failed_when: sessions.rc not in (0, 21)
Any command-line input or output is written as follows:
$ source ./hacking/env-setup
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