Comment 0 for bug 2045921

Maybe "race" isn't the right word, but the ordering of the Instance.save() of ERROR state and the creation of the instance.fault record can result in the instance.fault not having been created yet after the instance is visibly showing ERROR state.

Seen in the gate:

test_qos_min_bw_allocation_basic fails because the expected 'fault' field is missing in the server
Symptom: test_qos_min_bw_allocation_basic fails because the expected 'fault' field is not found in the server from GET /servers/{server_id}

testr_results.html:

testtools.matchers._impl.MismatchError: 'fault' not in {'id': '19b6c95f-b91b-4949-b72e-3f7fea0d1a49', 'name': 'tempest-MinBwAllocationPlacementTest-server-1096644195', 'status': 'ERROR', 'tenant_id': '1f52110a4e8649d78861c38daca6f179', 'user_id': '8ef9e2bc05034b03af2d7323155cb71f', 'metadata': {}, 'hostId': '', 'image': {'id': '3cb38f9c-a86e-47c8-984f-74efc924120c', 'links': [{'rel': 'bookmark', 'href': 'https://199.19.213.27/compute/images/3cb38f9c-a86e-47c8-984f-74efc924120c'}]}, 'flavor': {'vcpus': 1, 'ram': 128, 'disk': 1, 'ephemeral': 0, 'swap': 0, 'original_name': 'm1.nano', 'extra_specs': {'hw_rng:allowed': 'True'}}, 'created': '2023-12-07T15:00:24Z', 'updated': '2023-12-07T15:00:30Z', 'addresses': {}, 'accessIPv4': '', 'accessIPv6': '', 'links': [{'rel': 'self', 'href': 'https://199.19.213.27/compute/v2.1/servers/19b6c95f-b91b-4949-b72e-3f7fea0d1a49'}, {'rel': 'bookmark', 'href': 'https://199.19.213.27/compute/servers/19b6c95f-b91b-4949-b72e-3f7fea0d1a49'}], 'OS-DCF:diskConfig': 'MANUAL', 'OS-EXT-AZ:availability_zone': '', 'config_drive': '', 'key_name': None, 'OS-SRV-USG:launched_at': None, 'OS-SRV-USG:terminated_at': None, 'OS-EXT-STS:task_state': None, 'OS-EXT-STS:vm_state': 'error', 'OS-EXT-STS:power_state': 0, 'os-extended-volumes:volumes_attached': [], 'locked': False, 'description': None, 'tags': [], 'trusted_image_certificates': None, 'server_groups': []}

screen-placement-api.txt:

found no providers with 2147483647 NET_BW_IGR_KILOBIT_PER_SEC
this ^ is expected for this part of the test

OpenSearch query:

message:"testtools.matchers._impl.MismatchError: 'fault' not in"

Comments:

This may be a race because ERROR state is set on the instance and save()'ed before the 'fault' record is created
https://github.com/openstack/nova/blob/302e286408cce2c8df43d6742ca490405a20011d/nova/scheduler/utils.py#L902-L910
and the test waits for ERROR state before checking for the 'fault' field, so maybe sometimes it GETs the instance before the fault was able to be added
https://github.com/openstack/tempest/blob/a0b161bbde6d7734833a26ced76ca44b888fe152/tempest/scenario/test_network_qos_placement.py#L269-L276