[Bug 1994002] Re: [SRU] migration was active, but no RAM info was set

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Title:
  [SRU] migration was active, but no RAM info was set

Status in Ubuntu Cloud Archive:
  New
Status in Ubuntu Cloud Archive ussuri series:
  New
Status in QEMU:
  New
Status in qemu package in Ubuntu:
  New
Status in qemu source package in Focal:
  New
Status in qemu source package in Jammy:
  New
Status in qemu source package in Kinetic:
  New

Bug description:
  While live-migrating many instances concurrently, libvirt sometimes return internal error: migration was active, but no RAM info was set:
  ~~~
  2022-03-30 06:08:37.197 7 WARNING nova.virt.libvirt.driver [req-5c3296cf-88ee-4af6-ae6a-ddba99935e23 - - - - -] [instance: af339c99-1182-4489-b15c-21e52f50f724] Error monitoring migration: internal error: migration was active, but no RAM info was set: libvirt.libvirtError: internal error: migration was active, but no RAM info was set
  ~~~

  From upstream bug: https://bugzilla.redhat.com/show_bug.cgi?id=2074205

  [Impact]

   * Effects of this bug are mostly observed in large scale clusters with a lot of live migration activity.
   * Has second order effects for consumers of migration monitor such as libvirt and openstack.

  [Test Case]
  Steps to Reproduce:
  1. live evacuate a compute
  2. live migration of one or more instances fails with the above error

  N.B Due to the nature of this bug it is difficult consistently
  reproduce.

  [Where problems could occur]
   * In the event of a regression the migration monitor may report an inconsistent state.

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