Unnecessary "Instance not resizing, skipping migration" warning in n-cpu logs during live migration

[Matt Riedemann]

In a 7 day CI run, we have over 40K hits of this warning in the logs:

http://logstash.openstack.org/#dashboard/file/logstash.json?query=message%3A%5C%22Instance%20not%20resizing%2C%20skipping%20migration%5C%22%20AND%20tags%3A%5C%22screen-n-cpu.txt%5C%22&from=7d

http://logs.openstack.org/54/507854/4/gate/legacy-tempest-dsvm-multinode-live-migration/d723002/logs/subnode-2/screen-n-cpu.txt#_Apr_11_13_54_16_225676

Apr 11 13:54:16.225676 ubuntu-xenial-rax-dfw-0003443206 nova-compute[29642]: WARNING nova.compute.resource_tracker [None req-61a6f9c9-3355-4594-acfa-ebf31ba995aa tempest-LiveMigrationTest-1725408283 tempest-LiveMigrationTest-1725408283] [instance: 6f4923e3-bf1f-4cb7-bd37-00e5d437759e] Instance not resizing, skipping migration.

That warning was written back in 2012 when resize support was added to the resource tracker:

https://review.openstack.org/#/c/15799/

And since https://review.openstack.org/#/c/226411/ in 2015 it doesn't apply to evacuations.

We shouldn't see a warning in the nova-compute logs during a normal operation like a live migration, so we really should either just drop this down to debug or remove it completely.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/560467

[OpenStack Infra (hudson-openstack)]

Change abandoned by Matt Riedemann (<email address hidden>) on branch: master
Review: https://review.opendev.org/560467
Reason: Since https://review.opendev.org/#/c/634606/86/nova/compute/resource_tracker.py the merge conflict on this makes this no longer fixable on master, i.e. live migration is supported with move claims on master now. Given how low priority this is with not much interest it's likely not worth backporting at this point either.

[Matt Riedemann (mriedem)]

This is no longer valid on master (Train) due to this change:

https://review.opendev.org/#/c/634606/86/nova/compute/resource_tracker.py

I'm not sure it's worth trying to do a stable-only change to avoid the warning messages during live migration at this point since they have been around for years.