How To Write Ansible Playbooks

Introduction

Ansible is a modern configuration management tool that doesn’t require the use of an agent software on remote nodes. Instead, it uses only SSH and Python to communicate and execute commands on managed servers.

Ansible allows users to manage servers in two different ways: via ad hoc commands, and via playbooks. Playbooks are YAML files containing a list of ordered tasks that should be executed on a remote server to complete a task or reach a certain goal, such as to set up a LEMP environment. Ansible playbooks allow you to fully automate server setup and application deployment, using an accessible syntax and an extensive library of built-in resources.

This series will walk you through some of Ansible’s main features which you can use to write playbooks for server automation. At the end, you’ll create a playbook to automate setting up a remote Nginx web server and deploy a static HTML website to it. The playbook examples used in this series can be found in our ansible-practice repository at the DigitalOcean Community organization on GitHub.

Prerequisites

In order to follow along with the practical examples in this series, you’ll need:

• One Ansible Control Node: The Ansible control node is the machine we’ll use to connect to and control the Ansible hosts over SSH. Your Ansible control node can either be your local machine or a server dedicated to running Ansible, though this series assumes your control node is an Ubuntu 20.04 system. Make sure the control node has a non-root user with sudo privileges. To set this up, you can follow Steps 2 and 3 of our Initial Server Setup Guide for Ubuntu 20.04. However, please note that if you’re using a remote server as your Ansible Control node, you should follow every step of this guide. Doing so will configure a firewall on the server with ufw and enable external access to your non-root user profile, both of which will help keep the remote server secure.
• An SSH keypair associated with your control node’s non-root user. To set this up, you can follow Step 1 of our guide on How to Set Up SSH Keys on Ubuntu 20.04.
• One or more Ansible Hosts: An Ansible host is any machine that your Ansible control node is configured to automate. This guide assumes your Ansible hosts are remote Ubuntu 20.04 servers. Make sure each Ansible host has the Ansible control node’s SSH public key added to the authorized_keys of a system user. This user can be either root or a regular user with sudo privileges. To set this up, you can follow Step 2 of How to Set Up SSH Keys on Ubuntu 20.04.
• Ansible installed and configured on your control node. To set up Ansible, please follow our guide on How to Install and Configure Ansible on Ubuntu 20.04.
• A working Ansible inventory file. This inventory file should be set up on your control node and should contain all of your Ansible hosts. The guide How To Set Up Ansible Inventories explains in detail how you can create an Ansible inventory file.

Once you have met these prerequisites, run a connection test as outlined in our guide on How To Manage Multiple Servers with Ansible Ad Hoc Commands to make sure you’re able to connect and execute Ansible instructions on your remote nodes.