Comment 3 for bug 1639780

> And please clarify what you mean by "during upgrading Cinder".

As you know, currently Cinder supported the "rolling-upgrade" feature. "during upgrading Cinder", I mean that at that time, I finished upgrading cinder-volume to Newton release, cinder-api and cinder-scheduler are still Mitaka release. I cannot delete the volumes which I created before upgrading

One more thing, I am trying to get log from cinder volume as your request. I found a message in cinder-volume:

2016-11-09 13:41:29.618 ERROR oslo_messaging.rpc.server [-] Exception during message handling
2016-11-09 13:41:29.618 TRACE oslo_messaging.rpc.server Traceback (most recent call last):
2016-11-09 13:41:29.618 TRACE oslo_messaging.rpc.server File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/server.py", line 133, in _process_incoming
2016-11-09 13:41:29.618 TRACE oslo_messaging.rpc.server res = self.dispatcher.dispatch(message)
2016-11-09 13:41:29.618 TRACE oslo_messaging.rpc.server File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 157, in dispatch
2016-11-09 13:41:29.618 TRACE oslo_messaging.rpc.server raise UnsupportedVersion(version, method=method)
2016-11-09 13:41:29.618 TRACE oslo_messaging.rpc.server UnsupportedVersion: Endpoint does not support RPC version 1.40. Attempted method: delete_volume
2016-11-09 13:41:29.618 TRACE oslo_messaging.rpc.server

Maybe, I missed to configure in cinder.conf when starting cinder-volume. By the way, do you know the option in the cinder.conf file to pin version RPC?