OpenStack Configuration Example

The SUSE Cloud project contains a fully operational OpenStack implementation for Xen Project. It is an example of how to successfully employ Xen Project in OpenStack. This page attempts to document the Xen Project-specific configuration elements as an example of what a functional implementation might look like. As such, this page is less a "How To" and more a "What Is".

Where to Find the Configuration Files

The bulk of the Xen Project-specific entries will be in the Barclamp section of the Nova project within OpenStack. Most of these files can be found in the following trees:

• https://github.com/crowbar/barclamp-nova/blob/master/chef/cookbooks/nova/recipes/
• https://github.com/crowbar/barclamp-nova/blob/master/chef/cookbooks/nova/templates/default/

Recipes files

The following are the Xen Project-specific segments from compute.rb configuration file:

def set_boot_kernel_and_trigger_reboot(flavor='default')
# only default and xen flavor is supported by this helper right now
 default_boot = 0
 current_default = nil

 # parse menu.lst, to find boot index for selected flavor
  File.open('/boot/grub/menu.lst') do |f|
  f.lines.each do |line|
   current_default = line.scan(/\d/).first.to_i if line.start_with?('default')

   if line.start_with?('title')
   if flavor.eql?('xen')
    # found boot index
    break if line.include?('Xen')
   else
    # take first non-xen kernel as default
    break unless line.include?('Xen')
   end

  default_boot += 1
  end

 end
end

when "xen"
 %w{kernel-xen xen xen-tools openvswitch-kmp-xen}.each do |pkg|
  package pkg do
   action :install
  end
 end

service "xend" do
 action :nothing
 supports :status => true, :start => true, :stop => true, :restart => true
 # restart xend only when xen kernel is already present
 only_if { %x[uname -r].include?('xen') }
end

template "/etc/xen/xend-config.sxp" do
 source "xend-config.sxp.erb"
 group "root"
 owner "root"
 mode 0644
 variables(
  :node_platform => node[:platform],
  :libvirt_migration => node[:nova]["use_migration"],
  :shared_instances => node[:nova]["use_shared_instance_storage"],
  :libvirtd_listen_tcp => node[:nova]["use_migration"] ? 1 : 0,
  :libvirtd_listen_addr => Chef::Recipe::Barclamp::Inventory.get_network_by_type(node, "admin").address
 )
 notifies :restart, "service[xend]", :delayed
end

set_boot_kernel_and_trigger_reboot('xen')