Host groups

Two host groups always exist:

• The all host group contains every host explicitly listed in the inventory
• The ungrouped host group contains every host explicitly listed in the inventory that is not a member of any other group.

Nested groups

Specified by using :children suffix. Example:

[usa]
washington1.example.com
washington2.example.com

[canada]
ontario01.example.com
ontario02.example.com

[north-america:children]
canada
usa

Default location

/etc/ansible/hosts

To override use the -i switch.

Commands

# To list ungrouped hosts
ansible ungrouped --list-hosts

references: