Comment 11 for bug 1160442

After investigation: Problem would be a timout in the quantum client accessing the quantum service. Once this was increased the issues disappeared but it exposed the actual problem:

2013-06-04 10:46:20 ERROR [quantum.api.v2.resource] index failed
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/quantum/api/v2/resource.py", line 82, in resource
    result = method(request=request, **args)
  File "/usr/lib/python2.6/site-packages/quantum/api/v2/base.py", line 239, in index
    return self._items(request, True, parent_id)
  File "/usr/lib/python2.6/site-packages/quantum/api/v2/base.py", line 192, in _items
    obj_list = obj_getter(request.context, **kwargs)
  File "/usr/lib/python2.6/site-packages/quantum/plugins/openvswitch/ovs_quantum_plugin.py", line 597, in get_ports
    page_reverse)
  File "/usr/lib/python2.6/site-packages/quantum/db/db_base_plugin_v2.py", line 1433, in get_ports
    items = [self._make_port_dict(c, fields) for c in query.all()]
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2115, in all
    return list(self)
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2227, in __iter__
    return self._execute_and_instances(context)
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2240, in _execute_and_instances
    close_with_result=True)
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/orm/query.py", line 2231, in _connection_from_session
    **kw)
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/orm/session.py", line 730, in connection
    close_with_result=close_with_result)
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/orm/session.py", line 734, in _connection_for_bind
    return self.transaction._connection_for_bind(engine)
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/orm/session.py", line 267, in _connection_for_bind
    conn = bind.contextual_connect()
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/engine/base.py", line 2490, in contextual_connect
    self.pool.connect(),
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/pool.py", line 224, in connect
    return _ConnectionFairy(self).checkout()
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/pool.py", line 387, in __init__
    rec = self._connection_record = pool._do_get()
  File "/usr/lib64/python2.6/site-packages/SQLAlchemy-0.7.8-py2.6-linux-x86_64.egg/sqlalchemy/pool.py", line 729, in _do_get
    (self.size(), self.overflow(), self._timeout))
TimeoutError: QueuePool limit of size 5 overflow 10 reached, connection timed out, timeout 30