Wrong elapsed time logged during a live migration

Bug #1916031 reported by Belmiro Moreira
12
This bug affects 2 people
Affects Status Importance Assigned to Milestone
OpenStack Compute (nova)
Medium
Belmiro Moreira

Bug Description

In a recent VM live migration I noticed that the migration time reported in
the logs was not consistent with the actual time that it was taking:

```
2021-01-15 09:51:07.41 43553 INFO nova.virt.libvirt.driver [ ] Migration running for 0 secs, memory 100% remaining; (bytes processed=0, remaining=0, total=0)
2021-01-15 09:52:37.740 43553 DEBUG nova.virt.libvirt.driver [ ] Migration running for 5 secs, memory 100% remaining; (bytes processed=0, remaining=0, total=0)
2021-01-15 09:53:34.574 43553 DEBUG nova.virt.libvirt.driver [ ] Migration running for 10 secs, memory 100% remaining; (bytes processed=0, remaining=0, total=0)
2021-01-15 09:54:21.186 43553 DEBUG nova.virt.libvirt.driver [ ] Migration running for 15 secs, memory 100% remaining; (bytes processed=0, remaining=0, total=0)
(...)
```

This is because Nova doesn’t log the actual time that is taking. It cycles
to check the migration job status every 500ms and it logs the number of cycles/2.

Nova assumes that libvirt calls will report immediately, which was not the case. (In this particular example the compute node had issues and libvirt calls were taking a few seconds).

This behavior can cause some confusion when operators are debugging issues.

In my opinion Nova should log the real migration time.

Changed in nova:
assignee: nobody → Belmiro Moreira (moreira-belmiro-email-lists)
description: updated
Revision history for this message
Balazs Gibizer (balazs-gibizer) wrote :
Changed in nova:
status: New → In Progress
importance: Undecided → Medium
tags: added: live-migration
Revision history for this message
OpenStack Infra (hudson-openstack) wrote : Fix included in openstack/nova 23.0.0.0rc1

This issue was fixed in the openstack/nova 23.0.0.0rc1 release candidate.

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