Comment 0 for bug 1804502

Description
===========
server rebuild will fail in nova scheduler on NUMATopologyFilter if the computes do not have enough capacity (even though clearly the running server is already accounted into that calculation)

to resolve the issue a fix is required in NUMATopologyFilter to not perform the rebuild operation in the case that the request is due to rebuild.

the result of such a case will be that server rebuild will fail with error of "no valid host found"

(do not mix resize with rebuild functions...)

Steps to reproduce
==================

1. create a flavor that contain metadata that will point to a specific compute (use host aggregate with same key:value metadata
2. create a server on that compute (preferably using heat stack)
3. (try to) rebuild the server using stack update
4. issue reproduced

Expected result
===============
server in an active running state (if image was replaced in the rebuild command than with a reference to the new image in the server details.

Actual result
=============
server in error state with error of no valid host found.

Environment
===========
detected in Rocky release

KVM hypervisor

Ceph storage

Neutron networks

Logs & Configs
==============
in nova.conf:
enabled_filters=AggregateInstanceExtraSpecsFilter,RetryFilter,AvailabilityZoneFilter,NUMATopologyFilter,PciPassthroughFilter,RamFilter,ComputeFilter,ImagePropertiesFilter,CoreFilter,ServerGroupAntiAffinityFilter,ServerGroupAffinityFilter,DiskFilter,ComputeCapabilitiesFilter,AggregateRamFilter,SameHostFilter,DifferentHostFilter

logs: tbd