I should mention I'm also seeing this sporadically on 2011.3-0ubuntu2~ppa1~natty1, but it's a different table (FixedIp)

Session; lazy load operation of attribute 'network' cannot proceed
(nova.api): TRACE: Traceback (most recent call last):
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/api/ec2/__init__.py", line 347, in __call__
(nova.api): TRACE:     result = api_request.invoke(context)
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/api/ec2/apirequest.py", line 78, in invoke
(nova.api): TRACE:     result = method(context, **args)
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/api/ec2/cloud.py", line 1151, in describe_instances
(nova.api): TRACE:     instance_id=instance_id)
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/api/ec2/cloud.py", line 1160, in _format_describe_instances
(nova.api): TRACE:     return {'reservationSet': self._format_instances(context, **kwargs)}
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/api/ec2/cloud.py", line 1265, in _format_instances
(nova.api): TRACE:     if fixed['network'] and use_v6:
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/db/sqlalchemy/models.py", line 76, in __getitem__
(nova.api): TRACE:     return getattr(self, key)
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/attributes.py", line 163, in __get__
(nova.api): TRACE:     instance_dict(instance))
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/attributes.py", line 383, in get
(nova.api): TRACE:     value = callable_(passive=passive)
(nova.api): TRACE:   File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/strategies.py", line 595, in __call__
(nova.api): TRACE:     (mapperutil.state_str(state), self.key)
(nova.api): TRACE: DetachedInstanceError: Parent instance <FixedIp at 0x4330d50> is not bound to a Session; lazy load operation of attribute 'network' cannot proceed
(nova.api): TRACE: 

Additionally (and this should probably be it's own bug, so I can file it if necessary), when attempting to add source security groups I get:


2011-09-25 19:00:44,507 CRITICAL nova [-] Parent instance <SecurityGroup at 0x4f628d0> is not bound to a Session; lazy load operation of attribute 'instances' cannot proceed
(nova): TRACE: Traceback (most recent call last):
(nova): TRACE:   File "/usr/bin/nova-compute", line 49, in <module>
(nova): TRACE:     service.wait()
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/service.py", line 357, in wait
(nova): TRACE:     _launcher.wait()
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/service.py", line 107, in wait
(nova): TRACE:     service.wait()
(nova): TRACE:   File "/usr/local/lib/python2.7/dist-packages/eventlet/greenthread.py", line 166, in wait
(nova): TRACE:     return self._exit_event.wait()
(nova): TRACE:   File "/usr/local/lib/python2.7/dist-packages/eventlet/event.py", line 116, in wait
(nova): TRACE:     return hubs.get_hub().switch()
(nova): TRACE:   File "/usr/local/lib/python2.7/dist-packages/eventlet/hubs/hub.py", line 177, in switch
(nova): TRACE:     return self.greenlet.switch()
(nova): TRACE:   File "/usr/local/lib/python2.7/dist-packages/eventlet/greenthread.py", line 192, in main
(nova): TRACE:     result = function(*args, **kwargs)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/service.py", line 77, in run_server
(nova): TRACE:     server.start()
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/service.py", line 137, in start
(nova): TRACE:     self.manager.init_host()
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 181, in init_host
(nova): TRACE:     net_info)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/connection.py", line 1616, in ensure_filtering_rules_for_instance
(nova): TRACE:     network_info)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/firewall.py", line 546, in prepare_instance_filter
(nova): TRACE:     self.add_filters_for_instance(instance)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/firewall.py", line 582, in add_filters_for_instance
(nova): TRACE:     ipv4_rules, ipv6_rules = self.instance_rules(instance, network_info)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/firewall.py", line 702, in instance_rules
(nova): TRACE:     for instance in rule['grantee_group']['instances']:
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/db/sqlalchemy/models.py", line 76, in __getitem__
(nova): TRACE:     return getattr(self, key)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/attributes.py", line 163, in __get__
(nova): TRACE:     instance_dict(instance))
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/attributes.py", line 383, in get
(nova): TRACE:     value = callable_(passive=passive)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/strategies.py", line 595, in __call__
(nova): TRACE:     (mapperutil.state_str(state), self.key)
(nova): TRACE: DetachedInstanceError: Parent instance <SecurityGroup at 0x4f628d0> is not bound to a Session; lazy load operation of attribute 'instances' cannot proceed
(nova): TRACE: 

This is especially troubling, because it causes any rules after the offending one to not be applied and it keeps nova-compute from starting if there is an instance running in a group that has a source group specified.