I hit this while writing a functional recreate test for bug 1713786 where the destination node during an evacuate doesn't have it's allocations created by the scheduler. When the source node comes up after the evacuation, it tries to remove the allocations on the source node, which is the only one because of bug 1713786, but that results in sending a request like this:
2017-08-30 14:45:13,495 INFO [nova.scheduler.client.report] Sending updated allocation [{'resource_provider': {'uuid': '7ab9dab7-65c6-4961-9403-c8fc50dedb6b'}, 'resources': {}}] for instance dc8a686c-ad92-48f3-8594-d00c6e671a1c after removing resources for 7ab9dab7-65c6-4961-9403-c8fc50dedb6b.
And you get this stacktrace in the Placement API:
2017-08-30 14:45:13,502 ERROR [nova.api.openstack.placement.handler] Uncaught exception
Traceback (most recent call last):
File "nova/api/openstack/placement/handler.py", line 217, in __call__
return dispatch(environ, start_response, self._map)
File "nova/api/openstack/placement/handler.py", line 144, in dispatch
return handler(environ, start_response)
File "/home/user/git/nova/.tox/functional/local/lib/python2.7/site-packages/webob/dec.py", line 131, in __call__
resp = self.call_func(req, *args, **self.kwargs)
File "nova/api/openstack/placement/wsgi_wrapper.py", line 29, in call_func
super(PlacementWsgify, self).call_func(req, *args, **kwargs)
File "/home/user/git/nova/.tox/functional/local/lib/python2.7/site-packages/webob/dec.py", line 196, in call_func
return self.func(req, *args, **kwargs)
File "nova/api/openstack/placement/microversion.py", line 268, in decorated_func
return _find_method(f, version)(req, *args, **kwargs)
File "nova/api/openstack/placement/util.py", line 138, in decorated_function
return f(req)
File "nova/api/openstack/placement/handlers/allocation.py", line 286, in set_allocations
return _set_allocations(req, ALLOCATION_SCHEMA_V1_8)
File "nova/api/openstack/placement/handlers/allocation.py", line 252, in _set_allocations
allocations.create_all()
File "nova/objects/resource_provider.py", line 1877, in create_all
self._set_allocations(self._context, self.objects)
File "/home/user/git/nova/.tox/functional/local/lib/python2.7/site-packages/oslo_db/api.py", line 150, in wrapper
ectxt.value = e.inner_exc
File "/home/user/git/nova/.tox/functional/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
self.force_reraise()
File "/home/user/git/nova/.tox/functional/local/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
six.reraise(self.type_, self.value, self.tb)
File "/home/user/git/nova/.tox/functional/local/lib/python2.7/site-packages/oslo_db/api.py", line 138, in wrapper
return f(*args, **kwargs)
File "/home/user/git/nova/.tox/functional/local/lib/python2.7/site-packages/oslo_db/sqlalchemy/enginefacade.py", line 979, in wrapper
return fn(*args, **kwargs)
File "nova/objects/resource_provider.py", line 1835, in _set_allocations
consumer_id = allocs[0].consumer_id
IndexError: list index out of range
The schema validation on PUT /allocations requires a minimum of one provider in the request, but it doesn't validate that there is at least one resource for that provider:
https://github.com/openstack/nova/blob/da4083d7bc0a0c1272df35ecb12c4c2fd2102e21/nova/api/openstack/placement/handlers/allocation.py#L52-L61
what should the outcome be here:
* 400 you didn't follow the schema
* 204 we erased allocations for that resource provider