title: Live Migration Failure: unable to execute QEMU command 'migrate': Migration disabled: failed to allocate shared memory
body: <p>I have a 2 node OpenStack Mitaka environment consisting of a controller/compute node and a compute node.
  I've followed the setup guide to enable instance live migration using LVM block storage. I.e.: There's no shared storage backend, just local LVM block storage.</p>
  <p>Using OpenStack Horizon to perform the live migration a success message is displayed, however, the migration is far from successful. This worked pretty much out-of-the-box with our Juno installation. I've exhausted Google and cannot find any other instances of people facing the same problem. I thought it might have been a time synchronisation problem so have set both nodes to UTC. Still the problems persists.</p>
  <p><em><strong>Source machine /var/log/nova/nova-compute.log</strong></em></p>
  <blockquote>
  <p>2016-08-12 15:56:42.120 2230 ERROR nova.virt.libvirt.driver [req-b71ea7b0-5fa8-4b57-92d2-4edec62135c2 b017d86d1143461a92a267d4b912c104 88c686f09e1b427fb750f5c00716f84e - - -] [instance: 5763b6b6-370c-448c-8e8f-8b71eafaa8f1] <strong>Migration operation has aborted</strong></p>
  <p>2016-08-12 15:56:42.470 2230 ERROR nova.virt.libvirt.driver [req-b71ea7b0-5fa8-4b57-92d2-4edec62135c2 b017d86d1143461a92a267d4b912c104 88c686f09e1b427fb750f5c00716f84e - - -] [instance: 5763b6b6-370c-448c-8e8f-8b71eafaa8f1] <strong>Live Migration failure: internal error: unable to execute QEMU command 'migrate': Migration disabled: failed to allocate shared memory</strong></p>
  </blockquote>
  <p><em><strong>Target node /var/log/libvirt/libvirtd.log</strong></em></p>
  <blockquote>
  <p>2016-08-12 15:56:41.864+0000: 2170: error : qemuMonitorJSONGetMigrationStatsReply:2443 : internal error: info migration reply was missing return status</p>
  <p>2016-08-12 15:56:41.864+0000: 2170: error : virNetClientProgramDispatchError:177 : Cannot open log file: '/var/log/libvirt/qemu/instance-0000006a.log': Device or resource busy</p>
  </blockquote>
  <p>There are no other events captured in the source or target nova or libvirt logs.</p>
  <p>I should also note that I am trying to use <strong>qemu+tcp</strong> (libvirt listening enabled, default tcp port, no auth) rather than <strong>qemu+ssh</strong> in order to keep things simple while testing. In fact, I intend to only use qemu+tcp anyway.</p>