The document discusses developing an Ansible dynamic inventory script, emphasizing the importance of automation in DevOps. It outlines the differences between static and dynamic inventories, the requirements for writing a dynamic inventory script, and how to integrate it with the NetBox API as a data source. Additionally, it provides tips and resources for creating and managing the script effectively.

1. Developing Ansible
Dynamic Inventory Script
Ahmed AbouZaid
@aabouzaid

2. About
Ahmed AbouZaid
A passionate DevOps Engineer, author and Free/Open source geek
who loves the community.
Automation, data, and metrics are my preferred areas.
I have a built-in monitoring chip, and too lazy to do anything manually :D
Blog | Github | Twitter

3. Intro
● Ansible inventory.
● Ansible dynamic inventory.
● Write your own inventory script.
● Netbox external inventory script.
● Tips and tricks.

4. Ansible inventory
● Static file (default is INI-like, but could be YAML too).
● Define hosts, groups, and vars.
● Could be a directory has multiple inventory sources.
● Has many limitations and hard to manage.

5. Ansible dynamic inventory
● Dynamic data source (obviously).
● External data source like EC2 or OpenStack or whatever.
● Almost any source could be a dynamic inventory for ansible.

6. Ansible dynamic inventory script
● Scripts written in any programming language.
● Should return data in JSON format.
● Use a convention (”--list” to get all hosts, and “--host” to get one host).
● Example:
ansible -i netbox.py all -m ping

7. Netbox dynamic inventory script
● The script gets hosts lists via Netbox API as a dynamic data source.
● Netbox is an IPAM and DCIM tool from DigitalOcean
network engineering team, which serves as a "Source of Truth".
● I opened the PR on Feb 2017 and approved on Oct 2017.
● It has been reviewed by Ansible community (6 peoples were involved).
● Repos:
https://github.com/digitalocean/netbox
https://github.com/AAbouZaid/netbox-as-ansible-inventory

8. Related to script stuff:
● YAML or INI config file.
● Must be PEP8 compliant.
● Support Python 2.6/2.7 and 3.5/3.6.
● Avoid code smells (Ansible sanity, online services).
● Write unit test (e.g. pytest).
Tips & Tricks

9. Tips & Tricks
Around script stuff:
● Create its own repository.
● Create a setup.py file.
● Push it to PyPI (so it could be used with pip).
● Use CI to run tests (e.g. Travis CI).

10. Resources
● https://docs.ansible.com/ansible/latest/intro_inventory.html
● https://docs.ansible.com/ansible/latest/intro_dynamic_inventory.html
● https://docs.ansible.com/ansible/latest/dev_guide/developing_inventory.html

11. Questions?
Thanks :-)