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

Flushing the code cache

Everywhere in IT, caches are used to speed up operations, and Ansible is not an 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 they should not have 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 uses Redis 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...