Instances should not have soft-affinity with themselves.

[Mark Doffman]

When migrating instances should not have affinity with themselves.

This is most clearly seen with hard anti-affinity as an instance attempting to migrate to the same host would be unable to do so due to the presence of 'itself' on the host. (See bug #1558532).

In the soft-affinity case the consequences are not so dire, but can lead to incorrect weights being calculated. This is due to the fact that the soft affinity weigher counts the instance that is being migrated when looking at the number of instances from the group on a host.

See: https://github.com/openstack/nova/blob/master/nova/scheduler/weights/affinity.py#L49

[Charlotte Han (hanrong)]

related to https://bugs.launchpad.net/nova/+bug/1558532

I think this patch can modify this question.

https://review.openstack.org/#/c/299045/1/nova/scheduler/utils.py make instance's host is not contained with members = set(request_spec.instance_group.members).

But this patch Solution had been denied, because we don't this this _SoftAffinityWeigherBase.

[Markus Zoeller (markus_z) (mzoeller)]

Solving an inconsistency: This bug report has an assignee and it looks
like this will result in a patch. Therefore I switch the status to
"In Progress".
Dear assignee, please provide a patch in the next 2 weeks. If you stop
working on this report, please remove yourself as assignee and switch
the status back. If you need assistance, reach out on the IRC channel
#openstack-nova or use the mailing list.

[Sujitha (sujitha-neti)]

Its been a while this bug has been assigned and no patch was submitted. Removing assignee.

[Pushkar Umaranikar (pushkar-umaranikar)]

Solving Inconsistency: Since bug has priority set, Changing status from "new" to "confirmed".