Test-Driven Infrastructure Development with Chef

Stoyan Stoyanov

WeltN24 GmbH

22 April 2015

whoami

• Spreading the DevOps Cutlture @ Welt
• Worked as OPs, now more DEV
• Rubyist still doing a lot of  Java ..
• @s_stoyanoff

What is TDD?

• Red
• Green
• Refactor
• Do it over and over again

Choose your weapon

• version control !
• code reviews
• test-kitchen
  • serverspec
  • chefspec
  • minitest-chef-handler
  • kitchen-docker
  • kitchen-ec2
• rspec/minitest
• jenkins

Choose your weapon cont.

• Style conventions/Lint checks
  • rubocop
  • foodcritic
• Useful helpers
  • chef-zero
  • searchef

Organizing Code

• Follow the ruby conventions
• Don't put too much logic in the templates
  • Also use partial templates
• Move complex logic from the recipes in lightweight resources
• Pack pure ruby code in gems and test them separately (with rspec or minitest)

test-kitchen

• It's an orchestration tool
• We don't write tests in test-kitchen ;)
• It runs tests across multiple nodes
  • converges nodes
  • enables the use of different matchers
  • verifies the state of the nodes

test-kitchen (cont'd)

• Drivers
• Provisioners
• Platforms
• Suites

Use the proper driver for test-kitchen

• Quick feedback is fundamental
• The vagrant driver is slow for end-to-end runs
• Use kitchen converge and kitchen verify wisely
• Find the best for your case
  • kitchen-docker (with chef_container or baseimage-docker)
  • kitchen-ec2

---
driver:
  name: chef_container

provisioner:
  name: chef_zero
  client_rb:
    require: 'chef-init'

platforms:
  - name: ubuntu-14.04
    driver_config:
      socket: <%= ENV['DOCKER_HOST'] %>
      image: chef/ubuntu-14.04
      disable_upstart: false
      forward: 9300
      privileged: true
      use_sudo: false

suites:
  - name: java
    run_list:
      - recipe[es::java]
  - name: default
    run_list:
      - recipe[es::default]
    attributes: { es: { cluster_name: 'foo' } }
  - name: plugins
    run_list:
      - recipe[es::default]
      - recipe[es::plugins]

Demo

Challenges

• TDD hurts really hard at the beginning
• You must know what to test
• Many of the tools are under heavy development
  • But most of them are now stable
• Beware that Dockers are not VMs
• Integration with Jenkins is always tricky

Must Reads

• Test-Driven Infrastructure with Chef
• The RSpec Book
• Practical Object-Oriented Design in Ruby

• Growing Object-Oriented Software, Guided by Tests

Some Links

• Is TDD dead?
• serverspec advanced tips
• mysql-tests
• pid-1-problem
• cooking with jenkins
• chef-docker with centos