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:

• URL: URL of the git repository, mandatory
• INVENTORY: Path of the inventory file, mandatory
• SSHKEY: Path to an alternate SSH key, optional
• COMMIT: Commit to checkout (i.e. branch or tag), optional