After upgrade to RHEL 7.4 cinder-volume service fails to initialize the NetApp dataontap driver

Issue

After upgrading cinder host to RHEL 7.4 cinder-volume service start fails initializing the netapp dataontap driver:

2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager [req-c4e18bf4-77e0-4cf2-a60a-b7b9202476a3 - - - - -] Failed to initialize driver.
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager Traceback (most recent call last):
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/volume/manager.py", line 426, in init_host
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     self.driver.do_setup(ctxt)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 853, in trace_method_logging_wrapper
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     return f(*args, **kwargs)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 853, in trace_method_logging_wrapper
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     return f(*args, **kwargs)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/netapp/dataontap/nfs_cmode.py", line 72, in do_setup
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     vserver=self.vserver)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 853, in trace_method_logging_wrapper
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     return f(*args, **kwargs)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 853, in trace_method_logging_wrapper
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     return f(*args, **kwargs)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/netapp/dataontap/client/client_cmode.py", line 49, in __init__
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     (major, minor) = self.get_ontapi_version(cached=False)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 853, in trace_method_logging_wrapper
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     return f(*args, **kwargs)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/netapp/dataontap/client/client_base.py", line 71, in get_ontapi_version
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     res = self.connection.invoke_successfully(ontapi_version, False)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/netapp/dataontap/client/api.py", line 241, in invoke_successfully
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     result = self.send_http_request(na_element, enable_tunneling)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 863, in trace_api_logging_wrapper
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     return f(*args, **kwargs)
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager   File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/netapp/dataontap/client/api.py", line 226, in send_http_request
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager     raise NaApiError('Unexpected error')
2017-08-21 09:14:15.714 45363 ERROR cinder.volume.manager NaApiError: NetApp API failed. Reason - Unexpected error:unknown
2017-08-21 09:14:15.783 45363 INFO cinder.volume.manager [req-c4e18bf4-77e0-4cf2-a60a-b7b9202476a3 - - - - -] Initializing RPC dependent components of volume driver NetAppCmodeNfsDriver (1.0.0)
2017-08-21 09:14:15.797 45363 INFO os_brick.remotefs.remotefs [req-c4e18bf4-77e0-4cf2-a60a-b7b9202476a3 - - - - -] Already mounted: /var/lib/cinder/mnt/2d9632b9bd24045195919bcabb35e600
2017-08-21 09:14:15.797 45368 INFO os_brick.remotefs.remotefs [req-27d601dd-35f9-4180-8b64-6b04bf1702c8 - - - - -] Already mounted: /var/lib/cinder/mnt/c675535f8c0c2816a564b96037c7cf6c
2017-08-21 09:14:15.798 45368 WARNING cinder.volume.drivers.nfs [req-27d601dd-35f9-4180-8b64-6b04bf1702c8 - - - - -] The NAS file permissions mode will be 666 (allowing other/world read & write access). This is considered an insecure NAS environment. Please see http://docs.openstack.org/admin-guide-cloud/blockstorage_nfs_backend.html for information on a secure NFS configuration.
2017-08-21 09:14:15.799 45368 WARNING cinder.volume.drivers.nfs [req-27d601dd-35f9-4180-8b64-6b04bf1702c8 - - - - -] The NAS file operations will be run as root: allowing root level access at the storage backend. This is considered an insecure NAS environment. Please see http://docs.openstack.org/admin-guide-cloud/blockstorage_nfs_backend.html for information on a secure NAS configuration.
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service [req-c4e18bf4-77e0-4cf2-a60a-b7b9202476a3 - - - - -] Error starting thread.
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service Traceback (most recent call last):
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service   File "/usr/lib/python2.7/site-packages/oslo_service/service.py", line 680, in run_service
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service     service.start()
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service   File "/usr/lib/python2.7/site-packages/cinder/service.py", line 181, in start
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service     self.manager.init_host_with_rpc()
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service   File "/usr/lib/python2.7/site-packages/cinder/volume/manager.py", line 524, in init_host_with_rpc
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service     stats = self.driver.get_volume_stats(refresh=True)
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service   File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/remotefs.py", line 504, in get_volume_stats
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service     self._update_volume_stats()
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service   File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 853, in trace_method_logging_wrapper
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service     return f(*args, **kwargs)
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service   File "/usr/lib/python2.7/site-packages/cinder/utils.py", line 853, in trace_method_logging_wrapper
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service     return f(*args, **kwargs)
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service   File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/netapp/dataontap/nfs_cmode.py", line 152, in _update_volume_stats
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service     sync = True if self.ssc_vols is None else False
2017-08-21 09:14:15.798 45363 ERROR oslo_service.service AttributeError: 'NetAppCmodeNfsDriver' object has no attribute 'ssc_vols'