Specifying a destination node with nova live_migration does not take into account overcommit setting (ram_allocation_ratio)

[Sylvain Bauza]

When doing a nova live migration with a destination node specified, there is a different code path to check that there is enough memory on the destination than the case where no destination is specified.

The code path for the case when a destination is specified does not check whether we are allowing overcommit through the ram_allocation_ratio setting just because it bypasses the scheduler where the allocation logic is.

Since we're accepting that if the operator provides a target, all the scheduler policies are not checked then we should accept that this validation check should be removed.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/180151

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/180151
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=f5e35dcfe8ee586106438bcfa551426babc75bf6
Submitter: Jenkins
Branch: master

commit f5e35dcfe8ee586106438bcfa551426babc75bf6
Author: Sylvain Bauza <email address hidden>
Date: Thu Sep 17 17:51:06 2015 +0200

    Correct memory validation for live migration

    Since live migration has been moved to the conductor, there was no
    possibility for the conductor to verify if the destination had
    enough RAM just because it didn't know the allocation ratios given
    by the scheduler.

    Now that ComputeNodes provide a ram_allocation_field, we can fix
    that check and provide the same validation than RAMFilter to make
    sure that the destination is good.

    Closes-Bug: #1451831
    Closes-Bug: #1214943

    Change-Id: Ie6c768fc915553da73160ea51961078bfbacec77

[Thierry Carrez (ttx)]

This issue was fixed in the openstack/nova 13.0.0.0b1 development milestone.