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 portions are the Xen Project-specific segments from compute.rb:
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')
Template Files
Note that these examples use libvirt to integrate into OpenStack, not XAPI (aka XenAPI). Many of these files have extensive XenServer integration logic based on XAPI; this is not pertinent here.
The following portions are the Xen Project-specific segments from nova.conf.erb:
# Whether to use cow images (boolean value) <% if @libvirt_type.eql?('xen') -%> use_cow_images=false <% else -%> #use_cow_images=true <% end -%>
# Libvirt domain type (valid options are: kvm, lxc, qemu, uml, # xen) (string value) # Deprecated group/name - [DEFAULT]/libvirt_type virt_type=<%= @libvirt_type %>
<% if @libvirt_type.eql?('xen') -%> <% if @libvirt_migration and @shared_instances -%> # Migration target URI (any included "%s" is replaced with the # migration target hostname) (string value) live_migration_uri=xenmigr://%s/system # Migration flags to be set for live migration (string value) live_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_LIVE # Migration flags to be set for block migration (string value) #block_migration_flag=VIR_MIGRATE_UNDEFINE_SOURCE, VIR_MIGRATE_PEER2PEER, VIR_MIGRATE_NON_SHARED_INC <% end %>
The following portions are the Xen Project-specific segments from xend_config.sxp.erb:
The following portions are the Xen Project-specific segments from libvirtd.conf.erb: