Test-Driven Infrastructure with Chef

Test-Driven
Infrastructure with Chef
Principles & Tools

Today
① Testing Principles
② Chef Testing Tools
③ Continuous Integration

Write  
Test
Run Test 
(it fails)
Write  
Code
Test  
Passes
Refactor
TDD

BDD
TDDveriﬁcation of a unit of code
speciﬁcation of how code should
„behave“

Acceptance 
Tests
Integration 
Tests
Unit 
Tests

Today
✔

ChefSpec
• Unit Testing Framework for Chef Cookbooks
• Runs locally without converging a (virtual) machine

!"" site-cookbooks 
!"" pt_jenkins 
#"" recipes 
$ !"" default.rb 
!"" spec 
!"" default_spec.rb

execute "Install Jenkins from Ports" do 
command "cd #{node['pt_jenkins']['jenkins_port_dir']} && make install clean BATCH="YES"" 
not_if {File.exist?(node['pt_jenkins']['jenkins_war_file'])} 
end 
 
directory node['pt_jenkins']['jenkins_home'] do 
owner node['pt_jenkins']['jenkins_user'] 
group node['pt_jenkins']['jenkins_group'] 
mode '0766' 
action :create 
end 
 
node.default['user']['git_ssh_wrapper'] = "/tmp/git_ssh_wrapper" 
file node['user']['git_ssh_wrapper'] do 
owner node['pt_jenkins']['jenkins_user'] 
group node['pt_jenkins']['jenkins_group'] 
mode 0777 
content "/usr/bin/env ssh -A -o 'StrictHostKeyChecking=no' $1 $2" 
action :create 
end 
 
cookbook_file 'Copy private vagrant key' do 
path "/home/vagrant/.ssh/id_rsa" 
source 'vagrant_private_key' 
owner 'vagrant' 
group 'vagrant' 
backup false 
mode 0600 
action :create 
end 
 
cookbook_file 'Copy SSH config' do 
path "/home/vagrant/.ssh/config" 
source 'ssh_config' 
owner 'vagrant' 
group 'vagrant' 
backup false 
mode 0600 
action :create 
end 
 
service node['pt_jenkins']['jenkins_service'] do 
supports :status => true, :restart => true, :reload => true 
action [ :enable, :start ] 
end

require 'chefspec' 
 
RSpec.configure do |config| 
config.cookbook_path = [‚cookbooks','site-cookbooks'] 
config.role_path = 'roles' 
end 
 
describe 'pt_jenkins::default' do 
 
let(:chef_run) do 
ChefSpec::SoloRunner.new do |node| 
node.set['jenkins']['plugins'] = {} 
node.set['user']['git_ssh_wrapper'] = '/tmp/git_ssh_wrapper' 
end.converge(described_recipe) 
end 
 
it 'installs Jenkins from Ports' do 
expect(chef_run).to run_execute('Install Jenkins from Ports') 
end 
 
it 'creates a ssh wrapper file' do 
expect(chef_run).to create_file('/tmp/git_ssh_wrapper') 
end 
 
it 'copies the ssh config' do 
expect(chef_run).to create_cookbook_file('Copy SSH config') 
end 
 
it 'copies the private Vagrant key' do 
expect(chef_run).to create_cookbook_file('Copy private vagrant key') 
end 
 
it 'starts the Jenkins service' do 
expect(chef_run).to start_service('jenkins') 
end 
end

$ time bundle exec rspec site-cookbooks/pt_jenkins
pt_jenkins::default
installs Jenkins from Ports
creates a ssh wrapper file
copies the ssh config
copies the private Vagrant key
starts the Jenkins service
Finished in 0.34419 seconds
4 examples, 0 failures
1.43s user 0.24s system 76% cpu 2.186 total

Pros & Cons ChefSpec
Pro Contra
Fast White Box Testing
Can be run without
convergence
Harder to implement
Easy Setup Some tricky conﬁguration
Don’t know what system
looks like at the end

ServerSpec
• Describe desired state
• Check whether convergence result matches
expectations
• Platform independent
• Run it „from inside“ or „from outside“

$ gem install serverspec
$ serverspec-init
Select OS type:
1) UN*X
2) Windows
Select number: 1
Select a backend type:
1) SSH
2) Exec (local)
Select number: 1
Vagrant instance y/n: y
Auto-configure Vagrant from Vagrantfile? y/n: y

$ rake -T
rake spec:pttech # Run serverspec tests to pttech

#"" site-cookbooks 
$ !"" spec 
$ #"" pt 
$ $ !"" jenkins_spec.rb 
$ !"" spec_helper.rb 
!"" Rakefile

require 'serverspec' 
require 'net/ssh' 
require 'tempfile' 
 
set :backend, :ssh 
 
if ENV['ASK_SUDO_PASSWORD'] 
begin 
require 'highline/import' 
rescue LoadError 
fail "highline is not available. Try installing it." 
end 
set :sudo_password, ask("Enter sudo password: ") { |q| q.echo = false } 
else 
set :sudo_password, ENV['SUDO_PASSWORD'] 
end 
 
host = ENV['TARGET_HOST'] 
 
`vagrant up #{host}` 
 
config = Tempfile.new('', Dir.tmpdir) 
`vagrant ssh-config #{host} > #{config.path}` 
 
options = Net::SSH::Config.for(host, [config.path]) 
 
options[:user] ||= Etc.getlogin 
 
set :host, options[:host_name] || host 
set :ssh_options, options

require 'rake' 
require 'rspec/core/rake_task' 
 
task :spec => 'spec:all' 
task :default => :spec 
 
namespace :spec do 
targets = [] 
Dir.glob('./spec/*').each do |dir| 
next unless File.directory?(dir) 
targets << File.basename(dir) 
end 
 
task :all => targets 
task :default => :all 
 
targets.each do |target| 
desc "Run serverspec tests on #{target}" 
RSpec::Core::RakeTask.new(target.to_sym) do |t| 
ENV['TARGET_HOST'] = target 
t.pattern = "spec/#{target}/*_spec.rb" 
end 
end 
end

$ rake
Server contains
- jenkins.war at the expected location
- a folder /usr/local/jenkins, owned by user jenkins
- a folder /usr/local/jenkins, with mode 766

jenkins_config = JSON.parse(File.open("#{File.dirname(__FILE__)}/../../roles/jenkins.json").read) 
jenkins_config["override_attributes"]["jenkins"]["plugins"].each do | plugin_name, plugin_config | 
describe "Plugin: #{plugin_name}" do 
 
if plugin_config['enabled'] 
it "has expected .hpi file in plugins directory" do 
expect(file("/usr/local/jenkins/plugins/#{plugin_name}.hpi")).to be_file 
end 
end 
 
if plugin_config['pinned'] 
it "is marked as pinned and has the .hpi.pinned file in the plugins directory" do 
expect(file("/usr/local/jenkins/plugins/#{plugin_name}.hpi.pinned")).to be_file 
end 
it "is listed as pinned in the Jenkins plugin status" do 
expect(check_jenkins_plugin_pinned(plugin_name)).to be_truthy 
end 
else 
it "isn't marked as pinned and has no .hpi.pinned file in the plugins directory" do 
expect(file("/usr/local/jenkins/plugins/#{plugin_name}.hpi.pinned")).not_to be_file 
end 
end 
 
if plugin_config['version'] 
it "is version #{plugin_config['version']}" do 
expect(check_jenkins_plugin_version(plugin_name, plugin_config['version'])).to be_truthy 
end 
end 
 
end 
end

Pros & Cons ServerSpec
Pro Contra
Easy Setup
& well documented
No speciﬁc Feedback
Black Box Tests Requires running Machine
Small but mighty
command set
Slow
(Easily?) extendable
Can only be run once per
convergence Run

Test Kitchen
• Test and Infrastructure Management
• Interesting for Cookbook Development
• Quite some (configuration) overhead
• Good Tutorial
• Bad Documentation

--- 
driver: 
name: vagrant 
network: 
- ["private_network", {ip: "10.20.30.41", netmask: "255.255.255.0"}] 
 
provisioner: 
name: chef_zero 
require_chef_omnibus: false 
client_rb: 
cookbook_path: ["/var/chef/cookbooks", "/var/chef/site-cookbooks"] 
 
platforms: 
- name: FreeBSD-10-PtTech-TestKitchen 
driver: 
name: vagrant 
box: nanobsd-hosting-amd64.box-20140917 
box_url: http:/vagrantbox.es/some-box-to-use 
synced_folders: 
- [".", "/var/chef", "create: true, type: :nfs"] 
 
suites: 
- name: server 
run_list: 
- recipe[testkitchen] 
- role[jenkins] 
attributes:

Pros & Cons TestKitchen
Pro Contra
Handles complex Setups
„Touches“ your Machine
after Convergence
Multi-platform Testing for
Cookbook Development
No ServerSpec via ssh
implemented
„Standard“ in many
Tutorials
Requires machine startup
from Scratch
Many Plugins

Foodcritic
• Linting for Chef Cookbooks
• Complex Rule Set far beyond Code Indentation
• Goals (from Foodcritic Website)
• To make it easier to flag problems in your Cookbooks
• Faster feedback.
• Automate checks for common problems

$ gem install foodcritic
$ foodcritic site-cookbooks/pt_jenkins -t FC001
# FC001 Use strings in preference to symbols to access node attributes
FC001: Use strings in preference to symbols to access node attributes: 
site-cookbooks/pt_jenkins/attributes/default.rb:55
site-cookbooks/pt_jenkins/attributes/default.rb:56
site-cookbooks/pt_jenkins/recipes/default.rb:21

Further Testing Tools
• BATS: Bash Automated Testing System
• Shell Scripts 😟
• Cucumber Chef
• Great idea, but prototype state only
• Last commit > 1 year ago 😟

Today
✔
✔

Deployment Stage
Knife Upload to 
Chef Server
Acceptance Stage
Serverspec Test
Commit Stage
Build Project
ChefSpec Tests
Foodcritic
triggers uploads

Today
✔
✔
✔

http://serverspec.org/
https://github.com/sethvargo/chefspec
http://kitchen.ci/
http://acrmp.github.io/foodcritic/
https://sethvargo.com/unit-testing-chef-cookbooks/
http://leopard.in.ua/2013/12/01/chef-and-tdd/

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