Here is the trace:

2013-03-22 14:13:45.950 ERROR nova.compute.manager [req-9d363741-c3b1-4a1d-b87c-8084ceed2993 3ccf55fd609b45319f24fe681338886d 67b1c37f4ca64283908c7077e9e59997] [instance: 2fe0499d-7707-4447-879b-15093e7d1ee9] 'old_instance_type_memory_mb'. Setting instance vm_state to ERROR

2013-03-22 14:13:46.411 ERROR nova.openstack.common.rpc.amqp [req-9d363741-c3b1-4a1d-b87c-8084ceed2993 3ccf55fd609b45319f24fe681338886d 67b1c37f4ca64283908c7077e9e59997] Exception during message handling
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp Traceback (most recent call last):
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/openstack/common/rpc/amqp.py", line 393, in _process_data
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     rval = self.proxy.dispatch(ctxt, version, method, **args)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/openstack/common/rpc/dispatcher.py", line 133, in dispatch
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     return getattr(proxyobj, method)(ctxt, **kwargs)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/exception.py", line 120, in wrapped
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     temp_level, payload)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib64/python2.6/contextlib.py", line 23, in __exit__
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     self.gen.next()
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/exception.py", line 97, in wrapped
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     return f(self, context, *args, **kw)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/manager.py", line 265, in decorated_function
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     function(self, context, *args, **kwargs)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/manager.py", line 242, in decorated_function
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     e, sys.exc_info())
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib64/python2.6/contextlib.py", line 23, in __exit__
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     self.gen.next()
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/manager.py", line 229, in decorated_function
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     return function(self, context, *args, **kwargs)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/manager.py", line 1956, in confirm_resize
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     rt.confirm_resize(context, migration)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/resource_tracker.py", line 373, in confirm_resize
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     self.update_available_resource(elevated)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/openstack/common/lockutils.py", line 242, in inner
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     retval = f(*args, **kwargs)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/resource_tracker.py", line 269, in update_available_resource
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     self._update_usage_from_migrations(resources, migrations)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/resource_tracker.py", line 466, in _update_usage_from_migrations
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     migration)
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/resource_tracker.py", line 426, in _update_usage_from_migration
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     itype = instance_types.extract_instance_type(instance, 'old_')
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp   File "/usr/lib/python2.6/site-packages/nova/compute/instance_types.py", line 250, in extract_instance_type
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp     instance_type[key] = type_fn(sys_meta[type_key])
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp KeyError: 'old_instance_type_memory_mb'
2013-03-22 14:13:46.411 11393 TRACE nova.openstack.common.rpc.amqp

The Grizzly version:

35e2906530e8ded6643479f53df505e09d23f31b