nova.exception.NoValidHost: No valid host was found.
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager Traceback (most recent call last):
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/nova/conductor/manager.py", line 1346, in schedule_and_build_instances
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     instance_uuids, return_alternates=True)
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/nova/conductor/manager.py", line 800, in _schedule_instances
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     return_alternates=return_alternates)
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/nova/scheduler/client/query.py", line 42, in select_destinations
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     instance_uuids, return_objects, return_alternates)
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/nova/scheduler/rpcapi.py", line 160, in select_destinations
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     return cctxt.call(ctxt, 'select_destinations', **msg_args)
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/oslo_messaging/rpc/client.py", line 178, in call
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     retry=self.retry)
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/oslo_messaging/transport.py", line 128, in _send
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     retry=retry)
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/oslo_messaging/_drivers/amqpdriver.py", line 645, in send
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     call_monitor_timeout, retry=retry)
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/oslo_messaging/_drivers/amqpdriver.py", line 636, in _send
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     raise result
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager nova.exception_Remote.NoValidHost_Remote: No valid host was found.
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager Traceback (most recent call last):
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/oslo_messaging/rpc/server.py", line 229, in inner
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     return func(*args, **kwargs)
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager   File "/usr/lib/python3/dist-packages/nova/scheduler/manager.py", line 153, in select_destinations
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager     raise exception.NoValidHost(reason="")
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager nova.exception.NoValidHost: No valid host was found.
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager
2019-10-23 14:55:41.221 56921 ERROR nova.conductor.manager
2019-10-23 14:55:41.437 56921 WARNING nova.scheduler.utils [req-7750378d-e449-4eb6-bfe8-e488b758cff9 3390b35cd6554ceea033eae349d25d84 5eb7e7c90ac4474ca0a23fbda2536b29 - 7a3fcc1e0cd1420d83c438b4615f15b5 7a3fcc1e0cd1420d83c438b4615f15b5] Failed to compute_task_build_instances: No valid host was found.
Traceback (most recent call last):

  File "/usr/lib/python3/dist-packages/oslo_messaging/rpc/server.py", line 229, in inner
    return func(*args, **kwargs)

  File "/usr/lib/python3/dist-packages/nova/scheduler/manager.py", line 153, in select_destinations
    raise exception.NoValidHost(reason="")

nova.exception.NoValidHost: No valid host was found.
: nova.exception_Remote.NoValidHost_Remote: No valid host was found.
2019-10-23 14:55:41.438 56921 WARNING nova.scheduler.utils [req-7750378d-e449-4eb6-bfe8-e488b758cff9 3390b35cd6554ceea033eae349d25d84 5eb7e7c90ac4474ca0a23fbda2536b29 - 7a3fcc1e0cd1420d83c438b4615f15b5 7a3fcc1e0cd1420d83c438b4615f15b5] [instance: 33f451e3-9f80-40ff-a4a7-4aac85ef5377] Setting instance to ERROR state.: nova.exception_Remote.NoValidHost_Remote: No valid host was found.