group_policy flavor extra spec is not compatible with AggregateInstanceExtraSpecsFilter

[Pavlo Shchelokovskyy]

Effectively adding this extra spec to use the 'granular resource request' feature of placement also requires that all the computes such flavor attempts to target are added into an aggregate with the metadata 'group_policy' set and equal to 'none' or 'isolate'.

We either have to finally move the group_policy extra spec to its own namespace (there's a TODO in the code for that, similar to what has been done to hide_hypervisor_id),
or explicitly ignore this key in AggregateInstanceExtraSpecsFilter.

example:
using the flavor with the following extra spec

group_policy='none', resources1:CUSTOM_MIG_1G_5GB='1', resources2:CUSTOM_MIG_1G_5GB='1'

and having no aggregates, I get the following error in the scheduler log

2024-01-09 22:00:03.045 1 DEBUG nova.filters [None req-db963b93-798c-4289-93f6-52ad7054ac70 8f2db13a6c5c462bbe921c41d2beac3b d7355faecc8c45edb7d7de3837df6fd9 - - default default] Starting with 1 host(s) get_filtered_objects /var/lib/openstack/lib/python3.10/site-packages/nova/filters.py:70
2024-01-09 22:00:03.046 1 DEBUG nova.scheduler.filters.aggregate_instance_extra_specs [None req-db963b93-798c-4289-93f6-52ad7054ac70 8f2db13a6c5c462bbe921c41d2beac3b d7355faecc8c45edb7d7de3837df6fd9 - - default default] (kaas-node-f5f4a99c-6783-4b5f-b42a-0d772e1b0b11, kaas-node-f5f4a99c-6783-4b5f-b42a-0d772e1b0b11.kaas-kubernetes-4d64eb64810c48b3b5ac17da6a77eede) ram: 192851MB disk: 658432MB io_ops: 0 instances: 0, allocation_candidates: 6 fails flavor extra_specs requirements. Extra_spec group_policy is not in aggregate. host_passes /var/lib/openstack/lib/python3.10/site-packages/nova/scheduler/filters/aggregate_instance_extra_specs.py:63
2024-01-09 22:00:03.046 1 INFO nova.filters [None req-db963b93-798c-4289-93f6-52ad7054ac70 8f2db13a6c5c462bbe921c41d2beac3b d7355faecc8c45edb7d7de3837df6fd9 - - default default] Filter AggregateInstanceExtraSpecsFilter returned 0 hosts

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/nova/+/905210

[Amit Uniyal (auniyal)]

Hey pavlo, because you are working on it, I assigned it to you.