The nova-compute in my environment：
$ openstack compute service list --service nova-compute
+------+--------------+-----------+-------------+---------+-------+----------------------------+
|   ID | Binary       | Host      | Zone        | Status  | State | Updated At                 |
+------+--------------+-----------+-------------+---------+-------+----------------------------+
|  244 | nova-compute | compute02 | az1         | enabled | up    | 2021-05-14T02:50:55.000000 |
|  247 | nova-compute | compute01 | az1         | enabled | up    | 2021-05-14T02:50:54.000000 |
| 3381 | nova-compute | mgt06     | az1         | enabled | up    | 2021-05-14T02:50:53.000000 |
+------+--------------+-----------+-------------+---------+-------+----------------------------+
The service on the mgt06 node is nova-compute of ironic.

When I execute command, `tempest run --regex test_server_multinode.TestServerMultinode.test_schedule_to_all_nodes`, it failed,error logs are:

==============================
Failed 1 tests - output below:
==============================

tempest.scenario.test_server_multinode.TestServerMultinode.test_schedule_to_all_nodes[compute,id-9cecbe35-b9d4-48da-a37e-7ce70aa43d30,network,smoke]
----------------------------------------------------------------------------------------------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/tempest/common/utils/__init__.py", line 89, in wrapper
    return f(*func_args, **func_kwargs)

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/tempest/scenario/test_server_multinode.py", line 71, in test_schedule_to_all_nodes
    availability_zone='%(zone)s:%(host_name)s' % host)

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/tempest/scenario/manager.py", line 214, in create_server
    image_id=image_id, **kwargs)

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/tempest/common/compute.py", line 258, in create_test_server
    server['id'])

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/oslo_utils/excutils.py", line 220, in __exit__
    self.force_reraise()

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
    six.reraise(self.type_, self.value, self.tb)

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/six.py", line 703, in reraise
    raise value

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/tempest/common/compute.py", line 229, in create_test_server
    clients.servers_client, server['id'], wait_until)

      File "/opt/venvs/tempestenv/lib/python3.6/site-packages/tempest/common/waiters.py", line 76, in wait_for_server_status
    server_id=server_id)

    tempest.exceptions.BuildErrorException: Server ab7ccd0e-e2b2-4b45-9943-ee19044150d5 failed to build and is in ERROR status
Details: {'code': 500, 'created': '2021-05-14T02:35:59Z', 'message': 'No valid host was found. No such host - host: mgt06 node: None ', 'details': 'Traceback (most recent call last):\n  File "/var/lib/openstack/lib/python3.8/site-packages/nova/conductor/manager.py", line 1516, in schedule_and_build_instances\n    host_lists = self._schedule_instances(context, request_specs[0],\n  File "/var/lib/openstack/lib/python3.8/site-packages/nova/conductor/manager.py", line 887, in _schedule_instances\n    host_lists = self.query_client.select_destinations(\n  File "/var/lib/openstack/lib/python3.8/site-packages/nova/scheduler/client/query.py", line 41, in select_destinations\n    return self.scheduler_rpcapi.select_destinations(context, spec_obj,\n  File "/var/lib/openstack/lib/python3.8/site-packages/nova/scheduler/rpcapi.py", line 160, in select_destinations\n    return cctxt.call(ctxt, \'select_destinations\', **msg_args)\n  File "/var/lib/openstack/lib/python3.8/site-packages/oslo_messaging/rpc/client.py", line 175, in call\n    self.transport._send(self.target, msg_ctxt, msg,\n  File "/var/lib/openstack/lib/python3.8/site-packages/oslo_messaging/transport.py", line 123, in _send\n    return self._driver.send(target, ctxt, message,\n  File "/var/lib/openstack/lib/python3.8/site-packages/oslo_messaging/_drivers/amqpdriver.py", line 652, in send\n    return self._send(target, ctxt, message, wait_for_reply, timeout,\n  File "/var/lib/openstack/lib/python3.8/site-packages/oslo_messaging/_drivers/amqpdriver.py", line 644, in _send\n    raise result\nnova.exception_Remote.NoValidHost_Remote: No valid host was found. No such host - host: mgt06 node: None \nTraceback (most recent call last):\n\n  File "/var/lib/openstack/lib/python3.8/site-packages/oslo_messaging/rpc/server.py", line 241, in inner\n    return func(*args, **kwargs)\n\n  File "/var/lib/openstack/lib/python3.8/site-packages/nova/scheduler/manager.py", line 154, in select_destinations\n    resources = utils.resources_from_request_spec(\n\n  File "/var/lib/openstack/lib/python3.8/site-packages/nova/scheduler/utils.py", line 664, in resources_from_request_spec\n    raise exception.NoValidHost(reason=reason)\n\nnova.exception.NoValidHost: No valid host was found. No such host - host: mgt06 node: None \n\n'}

The mgt06 node cannot start the vm because the ironic driver needs a special flavor.