Practical Ansible 2

Automate infrastructure, manage configuration, and deploy applications with Ansible 2.9

Daniel Oh, James Freeman, Fabio Alessandro Locati

• Publisher: Packt Publishing
• Year: 2020
• Print ISBN:
  9781789807462
• eBook ISBN:
  9781789615418
• Edition: 1
• Topic: Informatica
• Subtopic: Amministrazione di sistemi

Leverage the power of Ansible to gain complete control over your systems and automate application deployment

Key Features

• Use Ansible 2.9 to automate and control your infrastructure
• Delve into advanced functionality such as plugins and custom modules in Ansible
• Automate and orchestrate major cloud platforms such as OpenStack, AWS, and Azure using Ansible

Book Description

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.

What you will learn

• Become familiar with the fundamentals of the Ansible framework
• Set up role-based variables and dependencies
• Avoid common mistakes and pitfalls when writing automation code in Ansible
• Extend Ansible by developing your own modules and plugins
• Contribute to the Ansible project by submitting your own code
• Follow best practices for working with cloud environment inventories
• Troubleshoot issues triggered during Ansible playbook runs

Who this book is for

If you are a DevOps engineer, administrator, or any IT professional looking to automate IT tasks using Ansible, this book is for you. Prior knowledge of Ansible is not necessary.

Section 1: Learning the Fundamentals of Ansible

In this section, we will take a look at the very fundamentals of Ansible. We will start with the process of installing Ansible and then we will get to grips with the fundamentals, including the basics of the language and ad hoc commands. We will then explore Ansible inventories, before looking at writing our very first playbooks and roles to complete multi-stage automation tasks.

This section contains the following chapters:

• Chapter 1, Getting Started with Ansible
• Chapter 2, Understanding the Fundamentals of Ansible
• Chapter 3, Defining Your Inventory
• Chapter 4, Playbooks and Roles

Getting Started with Ansible

Ansible enables you to easily deploy applications and systems consistently and repeatably using native communication protocols such as SSH and WinRM. Perhaps most importantly, Ansible is agentless and so requires nothing to be installed on the managed systems (except for Python, which, these days, is present on most systems). As a result, it enables you to build a simple yet robust automation platform for your environment.

Ansible is simple and straightforward to install and comes packaged for most modern systems. Its architecture is serverless as well as agentless, and so it has a minimal footprint. You can choose to run it from a central server or your own laptop—the choice is entirely yours. You can manage anything from a single host to hundreds of thousands of remote hosts from one Ansible control machine. All remote machines can be (with sufficient playbooks being written) managed by Ansible, and with everything created correctly, you may never have to log in to any of these machines individually again.

In this chapter, we will begin to teach you the practical skills to cover the very fundamentals of Ansible, starting with how to install Ansible on a wide variety of operating systems. We will then look at how to configure Windows hosts to enable them to be managed with Ansible automation, before delving into greater depth on the topic of how Ansible connects to its target hosts. We'll then look at node requirements and how to validate your Ansible installation, before finally looking at how to obtain and run the very latest Ansible source code if you wish to either contribute to its development or gain access to the very latest of features.

In this chapter, we will cover the following topics:

• Installing and configuring Ansible
• Understanding your Ansible installation
• Running from source versus pre-built RPMs

Technical requirements

Ansible has a fairly minimal set of system requirements—as such, you should find that if you have a machine (either a laptop, a server, or a virtual machine) that is capable of running Python, then you will be able to run Ansible on it. Later in this chapter, we will demonstrate the installation methods for Ansible on a variety of operating systems—it is hence left to you to decide which operating systems are right for you.

The one exception to the preceding statement is Microsoft Windows—although there are Python environments available for Windows, there is as yet no native build of Ansible for Windows. Readers running more recent versions of Windows will be able to install Ansible using Windows Subsystem for Linux (henceforth, WSL) and by following the procedures outlined later for their chosen WSL environment (for example, if you install Ubuntu on WSL, you should simply follow the instructions given in this chapter for installing Ansible on Ubuntu).

Installing and configuring Ansible

Ansible is written in Python and, as such, can be run on a wide range of systems. This includes most popular flavors of Linux, FreeBSD, and macOS. The one exception to this is Windows, where though native Python distributions exist, there is as yet no native Ansible build. As a result, your best option at the time of writing is to install Ansible under WSL proceeding as if you were running on a native Linux host.

Once you have established the system on which you wish to run Ansible, the installation process is normally simple and straightforward. In the following sections, we will discuss how to install Ansible on a wide range of different systems, so that most readers should be able to get up and running with Ansible in a matter of minutes.

Installing Ansible on Linux and FreeBSD

The release cycle for Ansible is usually about four months, and during this short release cycle, there are normally many changes, from minor bug fixes to major ones, to new features and even sometimes fundamental changes to the language. The simplest way to not only get up and running with Ansible but to keep yourself up to date is to use the native packages built for your operating system where they are available.

For example, if you wish to run the latest version of Ansible on top of Linux distribution such as CentOS, Fedora, Red Hat Enterprise Linux (RHEL), Debian, and Ubuntu, I strongly recommend that you use an operating system package manager such as yum on Red Hat-based distributions or apt on Debian-based ones. In this manner, whenever you update your operating system, you will update Ansible simultaneously.

Of course, it might be that you need to retain a specific version of Ansible for certain purposes—perhaps because your playbooks have been tested with this. In this instance, you would almost certainly choose an alternative installation method, but this is beyond the scope of this book. Also, it is recommended that, where possible, you create and maintain your playbooks in line with documented best practices, which should mean that they survive most Ansible upgrades.

The following are some examples showing how you might install Ansible on several Linux distributions:

• Installing Ansible on Ubuntu: To install the latest version of the Ansible control machine on Ubuntu, the apt packaging tool makes it easy using the following commands:

$ sudo apt-get update 
$ sudo apt-get install software-properties-common 
$ sudo apt-add-repository --yes --update ppa:ansible/ansible 
$ sudo apt-get install ansible

If you are running an older version of Ubuntu, you might need to replace software-properties-common with python-software-properties instead.

• Installing Ansible on Debian: You should add the following line into your /etc/apt/sources.list file:

deb http://ppa.launchpad.net/ansible/ansible/ubuntu trusty main

You will note that the word ubuntu appears in the preceding line of configuration along with trusty, which is an Ubuntu version. Debian builds of Ansible are, at the time of writing, taken from the Ansible repositories for Ubuntu and work without issue. You might need to change the version string in the preceding configuration according to your Debian build, but for most common use cases, the line quoted here will suffice.

Once this is done, you can install Ansible on Debian as follows:

$ sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 93C4A3FD7BB9C367 
$ sudo apt-get update 
$ sudo apt-get install ansible

• Installing Ansible on Gentoo: To install the latest version of the Ansible control machine on Gentoo, the portage package manager makes it easy with the following commands:

$ echo 'app-admin/ansible' >> /etc/portage/package.accept_keywords
$ emerge -av app-admin/ansible

• Installing Ansible on FreeBSD: To install the latest version of the Ansible control machine on FreeBSD, the PKG manager makes it easy with the following commands:

$ sudo pkg install py36-ansible
$ sudo make -C /usr/ports/sysutils/ansible install

• Installing Ansible on Fedora: To install the latest version of the Ansible control machine on Fedora, the dnf package manager makes it easy with the following commands:

$ sudo dnf -y install ansible

• Installing Ansible on CentOS: To install the la...

Table of contents

• Title Page
• Copyright and Credits
• About Packt
• Contributors
• Preface
• Section 1: Learning the Fundamentals of Ansible
• Getting Started with Ansible
• Understanding the Fundamentals of Ansible
• Defining Your Inventory
• Playbooks and Roles
• Section 2: Expanding the Capabilities of Ansible
• Consuming and Creating Modules
• Consuming and Creating Plugins
• Coding Best Practices
• Advanced Ansible Topics
• Section 3: Using Ansible in an Enterprise
• Network Automation with Ansible
• Container and Cloud Management
• Troubleshooting and Testing Strategies
• Getting Started with Ansible Tower
• Assessments
• Other Books You May Enjoy