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')
The following portions are the Xen Project-specific segments from xen.rb:
node.set[:nova][:libvirt_type] = "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 %>
# Override the default disk prefix for the devices attached to
# a server, which is dependent on virt_type. (valid options
# are: sd, xvd, uvd, vd) (string value)
# Deprecated group/name - [DEFAULT]/libvirt_disk_prefix
#disk_prefix=<None>
<%= "disk_prefix=xvd" if @libvirt_type.eql?('xen') %>
# Location where the Xen hvmloader is kept (string value)
#xen_hvmloader_path=/usr/lib/xen/boot/hvmloader
The following portions are the Xen Project-specific segments from xend-config.sxp.erb:
(xend-unix-server yes)
#
<% if @libvirt_migration -%>
(xend-relocation-server yes)
<% else %>
(xend-relocation-server no)
<% end %>
#
<% if @libvirt_migration -%>
(xend-relocation-address '<%= @libvirtd_listen_addr %>')
<% else %>
(xend-relocation-address )
<% end %>
#
<% if @libvirt_migration -%>
(xend-relocation-hosts-allow )
<% else %>
(xend-relocation-hosts-allow '^localhost$ ^localhost\\.localdomain$')
<% end %>
#
<% if @node_platform == "suse" -%>
(network-script )
(vif-script vif-bridge)
<% else %>
(network-script network-bridge)
(vif-script vif-bridge)
<% end %>
#
(dom0-min-mem 256)
(enable-dom0-ballooning yes)
(total_available_memory 0)
(dom0-cpus 0)
(vncpasswd )
The following portions are the Xen Project-specific segments from libvirtd.conf.erb:
Category:OpenStack
Category:libvirt
Category:Integration