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

The proper approach to defining group and host variables

When working with group and host variables, you can split them up using the directory-based approach we used in the The preferred directory layout section. However, there are a few additional pointers to managing this that you should be aware of. First and foremost, you should always pay attention to variable precedence. A detailed list of variable precedence order can be found at https://docs.ansible.com/ansible/latest/user_guide/playbooks_variables.html#variable-precedence-where-should-i-put-a-variable. However, the key takeaways for working with multiple environments are as follows:

  • Host variables are always of a higher order of precedence than group variables; so, you can override any group variable with a host variable. This behavior is useful if you take advantage of it in a controlled manner, but can yield unexpected...