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:
