Ansible

Simplistic tool for automating management of IT infrastructure

Provision.

Configure.

Manage.

Ansible

• no server component, push based
• control machine → SSH → managed nodes
• low requirements for managed nodes: SSH server allowing sudo-capable user, python 2.{4+simplejson,5}+
• no specific DSL
• works extensively with YAML and JSON ⇒ easy to extend and automate

Ansible

How it works

Ansible

How it looks

---
- apt:
    name: python-pip

- pip:
    name: docker-py

- docker:
    name: webapp1
    image: training/webapp
    command: python app.py
    ports: 8001:5000
					

Provisioning with Ansible on OpenStack

• Creating virtual machines, images, networks, floating IPs.
• {nova,glance,quantum,keystone}_* cloud modules in the Ansible core module set
• nova_compute module improved in 1.8
• can't create security groups
• demo ↓

Provisioning with Ansible on OpenStack: Summary

• The core OpenStack modules are kind of behind
• !!! Very interesting module set for OpenStack!!!, thanks Peter Jenkins from CSC for pointing me to this.
• An alternative to Heat?

Management/Orchestration: Ansible Inventory

• What does this mean?
• What is Ansible inventory, static and dynamic
• List of managed nodes and groups of them

mail.example.com

[webservers]
foo.example.com
bar.example.com

[dbservers]
one.example.com
two.example.com
three.example.com
					

Ansible Inventory on OpenStack

• nova inventory plugin ⇒ gets the list from Nova API with the Python client
• Grouping: cloud, region, tenant, custom hostgroups by metadata (nova boot --meta <key=value>)
• Access over private IP addresses
• I have improved the Nova inventory: pull request
• caching, guessing ssh user based on image name, refering to instances by Nova name, support for more tenants/regions/OpenStack
• demo ↓

Ansible Inventory on OpenStack: Summary

• I use combination of nova, .ssh/config and static alias for localhost: git repo

My workflow

• the whole process: ansible run on a vanilla Linux image
• to properly test the whole process, ansible-playbook toward a dev machine is not enough ← Goes for any conf management tool!
• need to automate from instance boot to ansible run
• OpenStack Python clients, custom scripts
• dependencies in requirements.yml, since 1.8 as good as librarians
• demo ↓

Workflow: summary

• Maybe better off with Vagrant
• Ansible-pull?