Cannot remove host from aggregate if host has been deleted

[Machi Hoshino]

Detailed bug description:
Customer is seeing the same issue of the following in mos9.0. Also this is reproducible in mos9.2. need to backport this fix.

https://bugs.launchpad.net/nova/+bug/1470341

Steps to reproduce:
Same as here https://bugs.launchpad.net/nova/+bug/1470341

Expected results:
Should remove the hosts from aggregate when the actual host is removed.

Actual result:
Hosts still stay in the aggregate even if the host is removed.

Reproducibility:
Always.

Workaround:
None.

Impact:
Low. Users are left behind we wrong information of the aggregate

Description of the environment:
- Operation system: Ubuntu 14.04
- Versions of components: MOS9.0
- Reference architecture:
- Network model: Neutron + OVS
- Related projects installed: None
Additional information:
None

[Alexander Rubtsov (arubtsov)]

sla2 for 9.0-updates

[Alexander Rubtsov (arubtsov)]

The corresponding commit for Mitaka series:
https://review.fuel-infra.org/#/c/37999/

[Fuel Devops McRobotson (fuel-devops-robot)]

Reviewed: https://review.fuel-infra.org/37999
Submitter: Pkgs Jenkins <email address hidden>
Branch: 9.0/mitaka

Commit: a0c139ffe5774be3ea5e8481326492419b3ebdfc
Author: Valeriy Saharov <email address hidden>
Date: Tue Mar 6 09:42:16 2018

Remove compute host from all host aggregates when compute service is deleted

Nova currently does not check if compute host included in host-aggregates when
user deletes compute service. It leads to inconsistency in nova host
aggregates, impossibility to remove compute host from host-aggregate or remove
host aggregate with invalid compute host.
This is backport of the fix for https://bugs.launchpad.net/nova/+bug/1470341

Change-Id: I8034da3827e47f3cd575e1f6ddf0e4be2f7dfecd
Closes-Bug: #1751958

[Vladimir Jigulin (vjigulin)]

Verified on 9.2-mu5-proposed