Chef::Lxc

Chef integration for LXC.

Installation

This library depends on ruby-lxc, a native liblxc binding.

Use standard rubygem way to install chef-lxc

$ gem install chef-lxc

Usage

There are three ways you can use chef-lxc.

• Use the command line tool
• Use the lxc resource/provider from any chef recipe
• Use the Chef::LXCHelper module from any arbitrary ruby script.

CLI examples

• Execute a chef recipe against a running container (like chef-apply)

  lxc-create -n test -t ubuntu
  lxc-start -n test -d
  chef-lxc test -e 'package "screen"' # via command line

or stream a recipe

echo 'package "vim"' | sudo bundle exec chef-lxc chef -s

or supply a file

chef-lxc test /path/to/recipe.rb

Chef resource/provider examples

• Create & manage containers (inside chef recipes), named web

  require 'chef/lxc'
  lxc "web"

A more elaborate example,

require 'chef/lxc'

lxc "web" do
  template "ubuntu"

  recipe do
    package "apache2"
    service "apache2" do
      action [:start, :enable]
    end
  end

  action [:create, :start]
end

Use Chef-Lxc from arbitrary ruby code

• Install openssh-server package on a vanilla un-privileged ubuntu container and change the default ubuntu user's password

  require 'lxc'
  require 'chef'
  require 'chef/lxc'
  
  include Chef::LXCHelper
  
  ct = LXC::Container.new('foo')
  ct.create('download', nil, {}, 0, %w{-a amd64 -r trusty -d ubuntu}) # reference: http://www.rubydoc.info/gems/ruby-lxc/LXC/Container#create-instance_method
  ct.start
  sleep 5 # wait till network is up and DHCP allocates the IP
  recipe_in_container(ct) do
    package 'openssh-server'
    execute 'echo "ubuntu:ubuntu" | chpasswd'
  end

Automating multi container setup

Chef-LXC provides Chef::LXC.create_fleet method to build chef managed multi container system. It offers helper methods to create containers and perform common chef administrative operations like creating roles, environments, databags etc.

Chef::LXC::Fleet can be used with chef-zero and berkshelf to test and prototype chef-solo or chef-client/server managed infrastructure easily.

Following is an example:

require 'chef/lxc'
require 'chef_zero/server'
require 'tempfile'
require 'berkshelf'

cookbook_path = File.expand_path('/tmp/cookbooks')

# Use berkshelf to venodirze cookbooks
berksfile = Berkshelf::Berksfile.from_file('/path/to/Berksfile')
berksfile.vendor('/tmp/cookbooks')

# Use chef zero as chef server, tell chef-zero to bind on lxcbr interface
server = ChefZero::Server.new(host: '10.0.3.1', port: 8889)
server.start_background

# Generate temporary client key for knife operations
tempfile = Tempfile.new('chef-lxc')
File.open(tempfile.path, 'w') do |f|
  f.write(server.gen_key_pair.first)
end


Chef::LXC.create_fleet('memcache') do |fleet|
  # Create base container with chef installed in it
  fleet.create_container('base') do |ct|
    ct.recipe do
      execute 'apt-get update -y'
      remote_file '/opt/chef_12.2.1-1_amd64.deb' do
        source 'http://opscode-omnibus-packages.s3.amazonaws.com/ubuntu/13.04/x86_64/chef_12.2.1-1_amd64.deb'
      end
      dpkg_package 'chef' do
        source '/opt/chef_12.2.1-1_amd64.deb'
      end
      directory '/etc/chef'
      file '/etc/chef/client.pem' do
        content ChefZero::Server.new.gen_key_pair.first
      end
      file '/etc/chef/client.rb' do
        content "chef_server_url 'http://10.0.3.1:8889'\n"
      end
    end
  end

  # configure chef setting for the chef zero server
  fleet.chef_config do |config|
    config[:client_key] = tempfile.path
    config[:node_name] = 'test'
    config[:chef_server_url] = 'http://10.0.3.1:8889'
  end

  # Upload cookbooks, data bags, create roles
  fleet.upload_cookbooks(cookbook_path)
  fleet.create_environment('sandbox')
  fleet.create_role('memcached', 'recipe[memcached]')
  fleet.create_role('db', 'recipe[mysel::server]')
  fleet.create_role('web', 'recipe[apache]', 'recipe[php]')

  fleet.create_container('memcached', from: 'base') do |ct|
    ct.command('chef-client -r role[memcached] -E sandbox')
  end
  fleet.create_container('db', from: 'base') do |ct|
    ct.command('chef-client -r role[mysql] -E sandbox')
  end
  fleet.create_container('web', from: 'base') do |ct|
    ct.command('chef-client -r role[web] -E sandbox')
  end
end

tempfile.unlink
server.stop

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request