<disk type='network' device='disk'>
  <driver name='qemu' type='raw' cache='writeback'/>
  <source protocol='rbd' name='volumes/volume-99ed8dd7-646e-4364-97a1-8cf5f11f5629'>
    <host name='nova-volume-lnx001' port='6789'/>
  </source>
  <target dev='vdd' bus='virtio'/>
</disk>