Ansible to rule the world

by Aitzol Naberan







Our systems background

  • 2001 ~ 2005: 3 shared servers
  • 2005 ~ 2009: n VPS
  • 2009 ~ today: m physical servers (20 < m < 30)
  • today ~ : ∞ cloud servers

But...

This was meant to be a nightmare

Automate, ok...

but WHAT to automate?

Application deployment

zc.buildout, fabric, ...

Already achieved

Our needs

  1. Server provisioning
  2. Configuration update/change

Ansible to the rescue

Ansible

Ansible is a radically simple IT automation engine that automates cloud provisioning, configuration management, application deployment, intra-service orchestration, and many other IT needs.

Ansible

  • Write a YAML file
  • Run it
  • Everything done

Ansible example


---
- hosts: all
  tasks:
    - name: Add user setlem
      user: name=setlem state=present shell=/bin/bash

    - name: Ensure additional packages via apt
      apt: pkg=nginx state=present

Extending ansible: Ansible galaxy

  • pypi for ansible
  • Roles for almost anything: package configuration, application deployment, swap files, exim configuration, ...

Our ansible setup

We ended having 5 main configuration files for our servers:

  • Common setup
  • Setup for Plone project
  • Setup for Django projects (Common + Mysql)
  • Setup for WordPress projects (Common - nginx + Apache + PHP + Mysql)
  • apt package update (we use Debian)

Our first time

  • After some tests, we run it on production
  • 4 servers with special firewall rules
  • 10 servers with old ssh keys
  • n incorrectly configured exim mail servers

Dynamic inventories

  • Dynamic list of hosts
  • No need to keep a stone-writen list of hosts
  • Everything automated

Current status

  • We create all our servers using Ansible
  • We regularly run Ansible to ensure that nobody has changed the configuration
  • We keep updating our Ansible config file to address a few glitches

(small) Problems

  • Server specific setups
  • Different firewall rules
  • Domain-dependant mailserver configuration
  • Project specific requirements

Future developments

  • Automate Plone hotfix installing
  • Automate django deployments
  • Automate nginx configuration
  • Autocontained projects: server setup + application deployment (DevOps culture)

Q & A