backend <module 'nova.db.sqlalchemy.api' from '/usr/lib/python2.7/dist-packages/nova/db/sqlalchemy/api.pyc'> from (pid=21840) __get_backend /usr/lib/python2.7/dist-packages/nova/utils.py:658
2012-09-12 20:12:06 WARNING nova.db.sqlalchemy.session [req-bbf9ec53-3303-4060-96d0-c1d4cc6ae29e None None] SQL connection failed. 10 attempts left.