2018-09-03 09:16:07.759 8690 ERROR oslo_service.service   File "/usr/lib64/python3.5/site-packages/nova/db/sqlalchemy/api.py", line 205, in wrapper
2018-09-03 09:16:07.759 8690 ERROR oslo_service.service     reader_mode = get_context_manager(context).async_
2018-09-03 09:16:07.759 8690 ERROR oslo_service.service 
2018-09-03 09:16:07.759 8690 ERROR oslo_service.service AttributeError: '_TransactionContextManager' object has no attribute 'async_'