Description

This is a dynamic inventory script for Ansible and the Ansible Tower. It reads hosts and groups from a git repositories' YAML file and "magically" transforms them into a dynamic inventory source for Ansible or the Ansible Tower API.

It has a few advantages over the static definition of hosts / groups in the Tower:

hosts and groups can be maintained directly in git next to the Ansible plays/roles/variables
host/group changes will be tagged together with the rest in the git repo
management of complex host/group structures get simplified
better overview thanks to the YAML instead of the WebUI

The provided YAML has a predefined layout, which is required for the scripts "magic" host group algorithm. Here's an example of a YAML file called prod.yml:

---
web:
    site1:
        - web1
        - web2
    site2:
        - web3
        - web4
db:
    site1:
        - db1
        - db2
    site2:
        - db3
        - db4

When the YAML file is parsed by the script, you'll have access to several host groups:

tier groups like web, db:
location groups like site1, site2:
tier-location groups like web-site1, web-site2, db-site1, db-site2

Because the file name is based on the environment, for example prod.yml, you also have access to environment based host groups:

env groups like prod
env-tier groups like prod-web, prod-db
env-location groups like prod-site1, prod-site2
env-tier-location groups like prod-web-site1, prod-web-site2, prod-db-site1, prod-db-site2

Installation

Ansible stand-alone script

Download a relase from this repository.
Install the requirements by executing

pip install -r requirements.txt

Ansible Tower (one-time)

Browse to the Ansible Tower WebUI
Login as an user with administration privileges
Click on the Administration icon on the upper right corner
Click on the Inventory Scripts link
Create a new Inventory Script by clicking on the + icon
Drag n' drop or copy-paste this script into the text field
Fill out the rest of the form and click Save

Configuration

Configure Tower Inventory

Open an existing inventory in the Ansible Tower WebUI
Create a new group by clicking the plus icon
Enter a name for the new (parent) group (e.g. dynamic)
Click on the Source tab
Select the custom script you've created in the last step

Please note you can / must set the following environment variables: