Ansible: Up and Running, 3rd Edition

Chapter 4. Inventory: Describing Your Servers

So far, we’ve been working with only one server (or host, as Ansible calls it). The simplest inventory is a comma-separated list of hostnames, which you can do even without a server:

$ ansible all -i 'localhost,' -a date

In reality, you’re going to be managing multiple hosts. The collection of hosts that Ansible knows about is called the inventory. In this chapter, you will learn how to describe a set of hosts as an Ansible inventory by creating an inventory that contains multiple machines.

Your ansible.cfg file should look like Example 4-1, which enables all inventory plug-ins explicitly.

Example 4-1. ansible.cfg

[defaults]
inventory = inventory

[inventory]
enable_plugins = host_list, script, auto, yaml, ini, toml

In this chapter, we will use a directory named inventory for the inventory examples. The Ansible inventory is a very flexible object: it can be a file (in several formats), a directory, or an executable, and some executables are bundled as plug-ins. Inventory plug-ins allow us to point at data sources, like your cloud provider, to compile the inventory. An inventory can be stored separately from your playbooks. This means that you can create one inventory directory to use with Ansible on the command line, with hosts running in Vagrant, Amazon EC2, Google Cloud Platform, or Microsoft Azure, or wherever you like!

Note

Serge van Ginderachter is the most knowledgeable person to read on Ansible inventory. See his blog for ...