Book Image

Practical Ansible - Second Edition

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

Practical Ansible - Second Edition

By: James Freeman, Fabio Alessandro Locati, Daniel Oh

Overview of this book

Ansible empowers you to automate a myriad of tasks, including software provisioning, configuration management, infrastructure deployment, and application rollouts. It can be used as a deployment tool as well as an 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 the latest release of Ansible and learn how 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 learn concepts such as playbooks, inventories, and roles. As you progress, you'll gain insight into the YAML syntax and learn how to port between Ansible versions. Additionally, you'll 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 all your IT challenges, from infrastructure-as-a-code provisioning to application deployments and handling mundane day-to-day maintenance tasks.
Table of Contents (21 chapters)
Free Chapter
1
Part 1:Learning the Fundamentals of Ansible
6
Part 2:Expanding the Capabilities of Ansible
12
Part 3:Using Ansible in an Enterprise

Flushing the code cache

Everywhere in IT, caches are used to speed up operations, and Ansible is no exception.

Usually, caches are good, and for this reason, they are heavily used ubiquitously. However, they might create some problems if they cache a value that should not have been cached or if they are not flushed, even if the value has changed.

Flushing caches in Ansible is very straightforward, and it’s enough to run ansible-playbook, which we are already running, with the addition of the --flush-cache option, as follows:

ansible-playbook -i inventory helloworld.yaml --flush-cache

Ansible can use multiple cache plugins to save host variables, as well as execution variables. Sometimes, those variables might be left behind and influence the following executions. When Ansible finds a variable that should be set in the step it just started, Ansible might assume that the step has already been completed, and therefore pick up that old variable as if it has just been...