Exception during network rescheduling

[Eugene Nikanorov]

Fuel 7.0 build #287

The following trace is seen in server logs:

2015-09-09 09:13:55.176 28608 ERROR neutron.db.agentschedulers_db [req-b228000d-37b0-4e50-a351-2eb7ecf37435 ] Failed to schedule network 0f85cf9c-ac6b-4a80-b42e-3317520499af
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db Traceback (most recent call last):
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/neutron/db/agentschedulers_db.py", line 201, in _schedule_network
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db agents = self.schedule_network(context, network)
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/neutron/db/agentschedulers_db.py", line 448, in schedule_network
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db self, context, created_network)
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/neutron/scheduler/base_scheduler.py", line 50, in schedule
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db self.resource_filter.bind(context, chosen_agents, resource['id'])
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/neutron/scheduler/dhcp_agent_scheduler.py", line 105, in bind
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db context.session.commit()
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 776, in commit
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db self.transaction.commit()
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 377, in commit
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db self._prepare_impl()
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 357, in _prepare_impl
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db self.session.flush()
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 1919, in flush
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db self._flush(objects)
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2037, in _flush
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db transaction.rollback(_capture_exception=True)
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db compat.reraise(exc_type, exc_value, exc_tb)
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2001, in _flush
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db flush_context.execute()
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 372, in execute
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db rec.execute(self)
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 526, in execute
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db uow
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 46, in save_obj
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db uowtransaction)
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 171, in _organize_states_for_save
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db state_str(existing)))
2015-09-09 09:13:55.176 28608 TRACE neutron.db.agentschedulers_db FlushError: New instance <NetworkDhcpAgentBinding at 0x7f51ab42fcd0> with identity key (<class 'neutron.db.agentschedulers_db.NetworkDhcpAgentBinding'>, (u'0f85cf9c-ac6b-4a80-b42e-3317520499af', u'92d95a58-f147-4bb5-9cd0-3a26e8392227')) conflicts with persistent instance <NetworkDhcpAgentBinding at 0x7f51af9ae390>

[Timur Nurlygayanov (tnurlygayanov)]

The the approximate steps to reproduce:
1. Deploy HA cloud
2. Create several networks
3. Get list of l3 and dhcp agents
4. Ban some agents and start network recheduling
5. Check logs

[Ilya Shakhat (shakhat)]

Eugene, please provide user impact info

[Alexander Ignatov (aignatov)]

Not enough information, user impact is unknown, won't fix for 7.0-updates

[Roman Podoliaka (rpodolyaka)]

No repro/feedback a month, closing as Invalid.