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[Bug 1659129] [NEW] n-api throws exception when listing servers

To: yahoo-eng-team@xxxxxxxxxxxxxxxxxxx
From: Tong Liu <lexuns@xxxxxxxxx>
Date: Tue, 24 Jan 2017 22:30:11 -0000
Reply-to: Bug 1659129 <1659129@xxxxxxxxxxxxxxxxxx>
Sender: bounces@xxxxxxxxxxxxx
Public bug reported:

When I tried to list all servers, n-api throws exception complaining
about "Unknow database exception". I am using master branch TOT version.

nicira@htb-1n-eng-dhcp8:~/devstack$ openstack server list
Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<class 'oslo_db.exception.DBNonExistentDatabase'> (HTTP 500) (Request-ID: req-4c779421-1c75-4e0a-b46f-ca2fe4995c25)


n-api log:
2017-01-24 19:51:27.176 DEBUG nova.compute.api [req-4c779421-1c75-4e0a-b46f-ca2fe4995c25 demo demo] Searching by: {'deleted': False, 'project_id': u'c1c62ff8a14348108d4519c65c3db3e1'} from (pid=9385) get_all /opt/stack/nova/nova/compute/api.py:2331
2017-01-24 19:51:27.194 ERROR nova.api.openstack.extensions [req-4c779421-1c75-4e0a-b46f-ca2fe4995c25 demo demo] Unexpected exception in API method
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions Traceback (most recent call last):
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/extensions.py", line 338, in wrapped
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return f(*args, **kwargs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/validation/__init__.py", line 181, in wrapper
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return func(*args, **kwargs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/validation/__init__.py", line 181, in wrapper
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return func(*args, **kwargs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/compute/servers.py", line 209, in detail
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     servers = self._get_servers(req, is_detail=True)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/compute/servers.py", line 344, in _get_servers
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     sort_keys=sort_keys, sort_dirs=sort_dirs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/compute/api.py", line 2416, in get_all
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     sort_dirs=sort_dirs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/compute/api.py", line 2493, in _get_instances_by_filters
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     expected_attrs=fields, sort_keys=sort_keys, sort_dirs=sort_dirs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_versionedobjects/base.py", line 184, in wrapper
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     result = fn(cls, context, *args, **kwargs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/objects/instance.py", line 1220, in get_by_filters
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     use_slave=use_slave, sort_keys=sort_keys, sort_dirs=sort_dirs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 235, in wrapper
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     with reader_mode.using(context):
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self.gen.next()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 944, in _transaction_scope
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     allow_async=self._allow_async) as resource:
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self.gen.next()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 558, in _session
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     bind=self.connection, mode=self.mode)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 317, in _create_session2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self._start()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 403, in _start
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     engine_args, maker_args)2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 427, in _setup_for_connection
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     sql_connection=sql_connection, **engine_kwargs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/engines.py", line 155, in create_engine
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     test_conn = _test_connection(engine, max_retries, retry_interval)2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/engines.py", line 331, in _test_connection
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return engine.connect()2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2018, in connect
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self._connection_cls(self, **kwargs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 72, in __init__
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     if connection is not None else engine.raw_connection()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2104, in raw_connection
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self.pool.unique_connection, _connection)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2078, in _wrap_pool_connect
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     e, dialect, self)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1401, in _handle_dbapi_exception_noconnection
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     util.raise_from_cause(newraise, exc_info)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     reraise(type(exception), exception, tb=exc_tb, cause=cause)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2074, in _wrap_pool_connect
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return fn()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 318, in unique_connection
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return _ConnectionFairy._checkout(self)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 713, in _checkout
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     fairy = _ConnectionRecord.checkout(pool)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 480, in checkout
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     rec = pool._do_get()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 1060, in _do_get
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self._dec_overflow()2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     compat.reraise(exc_type, exc_value, exc_tb)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 1057, in _do_get2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self._create_connection()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 323, in _create_connection
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return _ConnectionRecord(self)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 449, in __init__2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self.connection = self.__connect()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 607, in __connect2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     connection = self.__pool._invoke_creator(self)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/strategies.py", line 97, in connect
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return dialect.connect(*cargs, **cparams)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 385, in connect
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self.dbapi.connect(*cargs, **cparams)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/__init__.py", line 90, in Connect
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return Connection(*args, **kwargs)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 688, in __init__
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self.connect()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 906, in connect
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self._request_authentication()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 1114, in _request_authentication
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     auth_packet = self._read_packet()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 981, in _read_packet
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     packet.check_error()
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 393, in check_error
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     err.raise_mysql_exception(self._data)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/err.py", line 107, in raise_mysql_exception
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     raise errorclass(errno, errval)
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions DBNonExistentDatabase: (pymysql.err.InternalError) (1049, u"Unknown database 'nova_cell0'")
2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions
2017-01-24 19:51:27.202 INFO nova.api.openstack.wsgi [req-4c779421-1c75-4e0a-b46f-ca2fe4995c25 demo demo] HTTP exception thrown: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1659129

Title:
  n-api throws exception when listing servers

Status in OpenStack Compute (nova):
  New

Bug description:
  When I tried to list all servers, n-api throws exception complaining
  about "Unknow database exception". I am using master branch TOT
  version.

  nicira@htb-1n-eng-dhcp8:~/devstack$ openstack server list
  Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
  <class 'oslo_db.exception.DBNonExistentDatabase'> (HTTP 500) (Request-ID: req-4c779421-1c75-4e0a-b46f-ca2fe4995c25)

  
  n-api log:
  2017-01-24 19:51:27.176 DEBUG nova.compute.api [req-4c779421-1c75-4e0a-b46f-ca2fe4995c25 demo demo] Searching by: {'deleted': False, 'project_id': u'c1c62ff8a14348108d4519c65c3db3e1'} from (pid=9385) get_all /opt/stack/nova/nova/compute/api.py:2331
  2017-01-24 19:51:27.194 ERROR nova.api.openstack.extensions [req-4c779421-1c75-4e0a-b46f-ca2fe4995c25 demo demo] Unexpected exception in API method
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions Traceback (most recent call last):
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/extensions.py", line 338, in wrapped
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return f(*args, **kwargs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/validation/__init__.py", line 181, in wrapper
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return func(*args, **kwargs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/validation/__init__.py", line 181, in wrapper
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return func(*args, **kwargs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/compute/servers.py", line 209, in detail
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     servers = self._get_servers(req, is_detail=True)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/compute/servers.py", line 344, in _get_servers
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     sort_keys=sort_keys, sort_dirs=sort_dirs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/compute/api.py", line 2416, in get_all
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     sort_dirs=sort_dirs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/compute/api.py", line 2493, in _get_instances_by_filters
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     expected_attrs=fields, sort_keys=sort_keys, sort_dirs=sort_dirs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_versionedobjects/base.py", line 184, in wrapper
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     result = fn(cls, context, *args, **kwargs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/objects/instance.py", line 1220, in get_by_filters
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     use_slave=use_slave, sort_keys=sort_keys, sort_dirs=sort_dirs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/db/sqlalchemy/api.py", line 235, in wrapper
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     with reader_mode.using(context):
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self.gen.next()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 944, in _transaction_scope
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     allow_async=self._allow_async) as resource:
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self.gen.next()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 558, in _session
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     bind=self.connection, mode=self.mode)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 317, in _create_session2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self._start()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 403, in _start
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     engine_args, maker_args)2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 427, in _setup_for_connection
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     sql_connection=sql_connection, **engine_kwargs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/engines.py", line 155, in create_engine
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     test_conn = _test_connection(engine, max_retries, retry_interval)2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_db/sqlalchemy/engines.py", line 331, in _test_connection
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return engine.connect()2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2018, in connect
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self._connection_cls(self, **kwargs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 72, in __init__
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     if connection is not None else engine.raw_connection()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2104, in raw_connection
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self.pool.unique_connection, _connection)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2078, in _wrap_pool_connect
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     e, dialect, self)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1401, in _handle_dbapi_exception_noconnection
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     util.raise_from_cause(newraise, exc_info)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     reraise(type(exception), exception, tb=exc_tb, cause=cause)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2074, in _wrap_pool_connect
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return fn()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 318, in unique_connection
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return _ConnectionFairy._checkout(self)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 713, in _checkout
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     fairy = _ConnectionRecord.checkout(pool)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 480, in checkout
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     rec = pool._do_get()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 1060, in _do_get
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self._dec_overflow()2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     compat.reraise(exc_type, exc_value, exc_tb)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 1057, in _do_get2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self._create_connection()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 323, in _create_connection
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return _ConnectionRecord(self)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 449, in __init__2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self.connection = self.__connect()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 607, in __connect2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     connection = self.__pool._invoke_creator(self)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/strategies.py", line 97, in connect
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return dialect.connect(*cargs, **cparams)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 385, in connect
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return self.dbapi.connect(*cargs, **cparams)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/__init__.py", line 90, in Connect
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     return Connection(*args, **kwargs)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 688, in __init__
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self.connect()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 906, in connect
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     self._request_authentication()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 1114, in _request_authentication
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     auth_packet = self._read_packet()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 981, in _read_packet
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     packet.check_error()
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/connections.py", line 393, in check_error
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     err.raise_mysql_exception(self._data)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/pymysql/err.py", line 107, in raise_mysql_exception
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions     raise errorclass(errno, errval)
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions DBNonExistentDatabase: (pymysql.err.InternalError) (1049, u"Unknown database 'nova_cell0'")
  2017-01-24 19:51:27.194 TRACE nova.api.openstack.extensions
  2017-01-24 19:51:27.202 INFO nova.api.openstack.wsgi [req-4c779421-1c75-4e0a-b46f-ca2fe4995c25 demo demo] HTTP exception thrown: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.

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Follow ups

[Bug 1659129] Re: n-api throws exception when listing servers
From: Jordan Pittier, 2017-01-27