An introduction to

Ansible


Jake Clarkson
@jabclab

Talk overview

  • What is server automation?
  • Ansible introduction
  • Ansible topology + "real life" examples
  • Next steps with Ansible

What is server automation?

  • Creation of servers (+ load balancers, DNS etc.)
  • Provisioning of servers
  • Automation of deployments

Server automation: why?


Server automation: why?

  • Cloud becomes easier to use as it was intended
    • servers as horizontally scalable resources (e.g. Rackspace autoscale)
  • Less reliance on / coupling with specific cloud provider
  • Infrastructure in code
    • consistency across environments much easier
    • fringe cases easy to forget
    • much easier to deploy to many environments
    • less reliance on one person
    • facilitates automation, more people can release
    • easier to get new starters up and running
  • Disaster recovery
  • As developers in startups we wear multiple hats
    • DevOps: automate all the things
    • Make our lives easier, make managing servers less complex

Ansible

  • Open source (https://github.com/ansible/ansible)
  • Written in Python
    • modules can be written in any language that can return JSON
  • YAML configuration files
    • lots of small files but easy to maintain
  • Uses an agentless, SSH-based, model
  • Manages full code lifecycle
  • "Batteries included"
    • modules are included out of the box
  • Only requires one CLI invocation
  • No Windows (for control box)
  • Encryption capabilities out the box: easy to manage
  • Idempotent: f(x) = f(f(x))
    • get a box into a desired state

Ansible in its own words

  • Have a dead simple setup process and a minimal learning curve
  • Be super fast & parallel by default
  • Require no server or client daemons; use existing SSHd
  • Use a language that is both machine and human friendly
  • Focus on security and easy auditability/review/rewriting of content
  • Manage remote machines instantly, without bootstrapping
  • Allow module development in any dynamic language, not just Python
  • Be usable as non-root
  • Be the easiest IT automation system to use, ever.



https://github.com/ansible/ansible#design-principles

Other solutions






For a comprehensive list see: 
http://en.wikipedia.org/wiki/Comparison_of_open-source_configuration_management_software

Ansible: getting started

Installing:
(sudo) pip install ansible [--upgrade]

Can install via apt, yum, pkg, Homebrew in addition to from source




Ansible: structure

  • Inventory file = definition of your architecture
    • Static / dynamic supported
  • Playbooks
  • Roles
    • Tasks
    • Handlers
    • Variables
    • Files
    • Templates
    • Meta



Real-life setup

  • Ansible "control box"
    • Gateway to cloud (or dedicated) infrastructure
    • Single point of 'public' SSH security management
  • Cloud servers are built from image which, e.g. ansible@ansiblecontrol.$your_domain, can connect to


Ansible for workflow consistency

  • Ansible can manage environments from:
      • dev -> staging -> pre-production -> production
  • Ansible can be configured per environment (via variables/choice of playbook/inventory)


Ansible: further reading / meta

  • Ansible Tower
    • Front end to Ansible
    • Manage team privs etc.
    • RESTful API
    • Audit, scheduled jobs etc.
    • Fairly expensive ($5,000 p/a for enterprise support 50 nodes)
  • Ansible Galaxy
    • out-the-box Ansible roles
    • don't have to reinvent the wheel each time
    • still relatively new so not too mature
    • installed via simple CLI

Ansible community


Documentation
http://docs.ansible.com/index.html

GitHub
https://github.com/ansible/ansible

IRC
#ansible

Resources
http://www.ansible.com/resources

Google Group
https://groups.google.com/forum/#!forum/ansible-project

Ansible

By Jake Clarkson

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Ansible

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