Format for Ansible Inventory File

[Steven Williams]

Looking to see how others are formatting their ansible inventory files (hosts)

I can't seem to get the INI file formatting to work so I am working with YAML format. 

How do you build groups or group devices within this format? I have read the ansible documentation but do not really understand. The output doesn't read as I would expect. 

MacBook-Pro:ansible stevenwiliams$ cat hosts

all:

  hosts:

     cisco routers:

      hosts:

        R01:

        R02:

        R03:

        R04:

MacBook-Pro:ansible stevenwiliams$ ansible --list-hosts all

  hosts (1):

    cisco routers

MacBook-Pro:ansible stevenwiliams$

[gbekmezi-DD]

This is very old, but I'm going to respond in case someone stumbles across this in the future. Here's the format I've got working:

[mydevices]
host1.domain.com
host2.domain.com
host3.domain.com

[mydevices:vars]
ansible_become=no
ansible_become_method=enable
ansible_network_os=cisco.ios.ios
ansible_user=<username>
ansible_password=<password>