For the second run: ------------------- I have set the below parameters in /etc/neutron/neutron.conf. max_pool_size = 50 retry_interval = 10 max_overflow = 50 pool_max_size = 50 pool_max_overflow = 50 pool_timeout = 30 And also I have set the below parameters in nova.conf. max_pool_size = 50 max_overflow = 50 For the second run, I didn't get any ERROR messages in the neutron log. Only traces are found in nova log. Nova Logs: 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions [req-db3d6d66-9508-4eb8-be65-964f05ff50f8 admin admin] Unexpected exception in API method 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions Traceback (most recent call last): 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/api/openstack/extensions.py", line 338, in wrapped 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return f(*args, **kwargs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/api/openstack/compute/servers.py", line 914, in delete 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions self._delete(req.environ['nova.context'], req, id) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/api/openstack/compute/servers.py", line 755, in _delete 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions instance = self._get_server(context, req, instance_uuid) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/api/openstack/compute/servers.py", line 382, in _get_server 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions expected_attrs=expected_attrs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/api/openstack/common.py", line 496, in get_instance 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions expected_attrs=expected_attrs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/compute/api.py", line 2215, in get 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions expected_attrs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/compute/api.py", line 2198, in _get_instance 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions context, instance_uuid, expected_attrs=expected_attrs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/oslo_versionedobjects/base.py", line 184, in wrapper 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions result = fn(cls, context, *args, **kwargs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/objects/instance.py", line 444, in get_by_uuid 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions use_slave=use_slave) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 225, in wrapper 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return f(*args, **kwargs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/objects/instance.py", line 436, in _db_instance_get_by_uuid 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions columns_to_join=columns_to_join) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/db/api.py", line 725, in instance_get_by_uuid 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return IMPL.instance_get_by_uuid(context, uuid, columns_to_join) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 169, in wrapper 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return f(*args, **kwargs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 270, in wrapped 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return f(context, *args, **kwargs) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 1867, in instance_get_by_uuid 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions columns_to_join=columns_to_join) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 1872, in _instance_get_by_uuid 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions filter_by(uuid=uuid).\ 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2659, in first 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions ret = list(self[0:1]) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2457, in __getitem__ 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return list(res) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2761, in __iter__ 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return self._execute_and_instances(context) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2774, in _execute_and_instances 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions close_with_result=True) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2765, in _connection_from_session 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions **kw) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 893, in connection 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions execution_options=execution_options) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 898, in _connection_for_bind 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions engine, execution_options) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 334, in _connection_for_bind 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions conn = bind.contextual_connect() 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2039, in contextual_connect 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions self._wrap_pool_connect(self.pool.connect, None), 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2074, in _wrap_pool_connect 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return fn() 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 376, in connect 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions return _ConnectionFairy._checkout(self) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 713, in _checkout 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions fairy = _ConnectionRecord.checkout(pool) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 480, in checkout 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions rec = pool._do_get() 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 1053, in _do_get 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions (self.size(), self.overflow(), self._timeout)) 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions TimeoutError: QueuePool limit of size 50 overflow 50 reached, connection timed out, timeout 30 2016-11-03 17:27:34.146 2399 ERROR nova.api.openstack.extensions 2016-11-03 17:27:34.148 2399 INFO nova.api.openstack.wsgi [req-db3d6d66-9508-4eb8-be65-964f05ff50f8 admin admin] HTTP exception thrown: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible. 2016-11-03 17:27:34.148 2399 DEBUG nova.api.openstack.wsgi [req-db3d6d66-9508-4eb8-be65-964f05ff50f8 admin admin] Returning 500 to user: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible. __call__ /opt/stack/nova/nova/api/openstack/wsgi.py:1044