Book Image

Practical Ansible 2

By : Daniel Oh, James Freeman, Fabio Alessandro Locati
Book Image

Practical Ansible 2

By: Daniel Oh, James Freeman, Fabio Alessandro Locati

Overview of this book

Ansible enables you to automate software provisioning, configuration management, and application roll-outs, and can be used as a deployment and orchestration tool. While Ansible provides simple yet powerful features to automate multi-layer environments using agentless communication, it can also solve other critical IT challenges, such as ensuring continuous integration and continuous deployment (CI/CD) with zero downtime. In this book, you'll work with Ansible 2.9 and learn to solve complex issues quickly with the help of task-oriented scenarios. You'll start by installing and configuring Ansible on Linux and macOS to automate monotonous and repetitive IT tasks and get to grips with concepts such as playbooks, inventories, and network modules. As you progress, you'll gain insight into the YAML syntax and learn how to port between Ansible versions. In addition to this, you'll also understand how Ansible enables you to orchestrate multi-layer environments such as networks, containers, and the cloud. By the end of this Ansible book, you'll be well - versed in writing playbooks and other related Ansible code to overcome just about all of your IT challenges, from infrastructure-as-code provisioning to application deployments, and even handling the mundane day-to-day maintenance tasks that take up so much valuable time.
Table of Contents (18 chapters)
1
Section 1: Learning the Fundamentals of Ansible
6
Section 2: Expanding the Capabilities of Ansible
11
Section 3: Using Ansible in an Enterprise

Defining variables

In this section, we will cover the topic of variables and how they can be defined in Ansible. You will learn how variables should be defined step by step and understand how to work with them in Ansible.

Although automation removes much of the repetition from previously manual tasks, not every single system is identical. If two systems differ in some minor way, you could write two unique playbooks—one for each system. However, this would be inefficient and wasteful, as well as difficult to manage as time goes on (for example, if the code in one playbook is changed, how can you ensure that it is updated in the second variant?).

Equally, you might need to use a value from one system in another—perhaps you need to obtain the hostname of a database server and make it available to another. All of these issues can be addressed with variables as they...