Inventory File

Inventory defines the groups of hosts which are alike in any way. For example, you would want to group your web servers in one group and application servers in another. A group can have multiple server and one server can be a part of multiple groups.

Name of group is enclosed in square brackets []. Server names can be their DNS names or IP addresses.

[webservers]
server1
[application]
server1
server2

By default, ansible looks for the inventory file at /etc/ansible/hosts, but that can be modified by passing a -i <inventory_path to the ansible command line.

We can modify the way ansible connects to our hosts by supplying additional information in the inventory file.

[webservers]
server1 ansible_port=4242 ansible_user=adimania
[application]
server1
server2
[master]
localhost ansible_connection=local

A more exhaustive list of inventory parameters can be seen here - http://docs.ansible.com/ansible/intro_inventory.html#list-of-behavioral-inventory-parameters

There are times when you would want to pull the inventory from a cloud provider, or from LDAP, or you would want the inventory list to be generated using some logic, rather than from a simple text-based inventory list. For such purposes, we can use Dynamic Inventory, but that’s a topic for another day.