Dynamic Inventory

Ansible provides a basic text-based system as described in Inventory. And it easily supports all of these options via an external invnetory system.

Example. AWS EC2 External Inventory Script

You can use this script in one of two ways. The easiest is to use Ansible’s -i command line option and specify the path to the script after marking it executable:

ansible -i ec2.py -u ubuntu us-east-1d -m ping

The second option is to copy the script to /etc/ansible/hosts and chmod +x it. You will also need to copy the ec2.ini file to /etc/ansible/ec2.ini

Using Multiple Inventory Sources

If the location given to -i in Ansible is a directory, Ansible can use multiple inventory sources at the same time.

Static Groups of Dynamic Groups

When defining a static group of dynamic child groups, define the dynamic groups as empty in the static inventory file:




Developing Dynamic Inventory Sources

You just need to create a script or program that can return JSON in the right format when fed the proper arguments.

Script Conventions

When the external node script is called with the single argument --list , the script must return a JSON dictionary of all the groups to be managed.

    "hosts": ["host01", "host02"],
    "vars": {
      "foo": bar,
      "flag": true
  "webservers":["web01", "web02"],
    "hosts":["backend01", "backend02"],
      "local": false

When called with the arguments --host <hostname> , the script must return either an empty JSON dictionary, or a dictionary of variables to make available to templates and playbooks.