I ran into this upgrading another environment into Rocky, deleted the problematic resource provider, but just ran into it again in another upgrade of another environment so there's something wonky. Here's the traceback:
=============
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap [req-8ad1c999-7646-4b0a-91c0-cd26a3581766 b61d42657d364008bfdc6fa715e67daf a894e8109af3430aa7ae03e0c49a0aa0 - default default] Placement API unexpected error: 19: KeyError: 19
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap Traceback (most recent call last):
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/fault_wrap.py", line 40, in __call__
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return self.application(environ, start_response)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/webob/dec.py", line 129, in __call__
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap resp = self.call_func(req, *args, **kw)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/webob/dec.py", line 193, in call_func
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return self.func(req, *args, **kwargs)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/microversion_parse/middleware.py", line 80, in __call__
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap response = req.get_response(self.application)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/webob/request.py", line 1313, in send
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap application, catch_exc_info=False)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/webob/request.py", line 1277, in call_application
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap app_iter = application(self.environ, start_response)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/handler.py", line 209, in __call__
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return dispatch(environ, start_response, self._map)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/handler.py", line 146, in dispatch
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return handler(environ, start_response)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/webob/dec.py", line 129, in __call__
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap resp = self.call_func(req, *args, **kw)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/wsgi_wrapper.py", line 29, in call_func
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap super(PlacementWsgify, self).call_func(req, *args, **kwargs)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/webob/dec.py", line 193, in call_func
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return self.func(req, *args, **kwargs)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/microversion.py", line 164, in decorated_func
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return _find_method(f, version, status_code)(req, *args, **kwargs)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/util.py", line 81, in decorated_function
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return f(req)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/handlers/allocation_candidate.py", line 316, in list_allocation_candidates
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap context, requests, limit=limit, group_policy=group_policy)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/objects/resource_provider.py", line 3965, in get_by_requests
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap context, requests, limit=limit, group_policy=group_policy)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/oslo_db/sqlalchemy/enginefacade.py", line 993, in wrapper
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return fn(*args, **kwargs)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/objects/resource_provider.py", line 4071, in _get_by_requests
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap context, request, sharing, has_trees)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/objects/resource_provider.py", line 4045, in _get_by_one_request
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap return _alloc_candidates_single_provider(context, resources, rp_ids)
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap File "/usr/lib/python2.7/site-packages/nova/api/openstack/placement/objects/resource_provider.py", line 3490, in _alloc_candidates_single_provider
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap rp_summary = summaries[rp_id]
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap KeyError: 19
2018-10-25 09:18:29.853 7431 ERROR nova.api.openstack.placement.fault_wrap
=============
The resource provider (nova-compute) with ID 19 was down during the upgrade (it was put down for a long time ago). The only oddities I found was in the database, `root_provider_id` was set to NULL for that record too. Upon deleting the resource provider, the placement API stopped giving 500s when it tried to schedule new VMs.
In the other environment that had a problem too, it actually was the downed instance as well.
Related fix proposed to branch: master /review. openstack. org/613304
Review: https:/