Description of problem:

cinder-backup service unable to access the volumes on ipv6 controller.

Version-Release number of selected component (if applicable):
rhosp12/openstack-iscsid-docker:2017-08-31.2 
openstack-tripleo-heat-templates-7.0.0-0.20170821194254.el7ost

How reproducible:
always

Steps to Reproduce:
- ipv6, 3 controller, 1 compute setup, lvm/iscsi
- run tempest backup tests

Additional info:
- ipv4 version works
- non-containerized version works


c-bak log:

packages/oslo_concurrency/processutils.py:355
2017-09-05 00:11:13.222 242976 DEBUG oslo_concurrency.processutils [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] CMD "iscsiadm -m node" returned: 21 in 0.005s execute /usr/lib/python2.7/site-packages/oslo_concurrency/processutils.py:385
2017-09-05 00:11:13.222 242976 DEBUG oslo.privsep.daemon [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] privsep: reply[110782256]: (4, ('', 'iscsiadm: No records found\n')) loop /usr/lib/python2.7/site-packages/oslo_privsep/daemon.py:456
2017-09-05 00:11:13.223 120862 WARNING os_brick.initiator.connectors.iscsi [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] Couldn't find iSCSI nodes because iscsiadm err: iscsiadm: No records found
: VolumeDeviceNotFound: Volume device not found at .
2017-09-05 00:11:13.224 242976 DEBUG oslo.privsep.daemon [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] privsep: request[110782256]: (3, 'os_brick.privileged.rootwrap.execute_root', ('iscsiadm', '-m', 'session'), {'check_exit_code': (0, 1, 21, 255)}) loop /usr/lib/python2.7/site-packages/oslo_privsep/daemon.py:443
2017-09-05 00:11:13.224 242976 DEBUG oslo_concurrency.processutils [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] Running cmd (subprocess): iscsiadm -m session execute /usr/lib/python2.7/site-packages/oslo_concurrency/processutils.py:355
2017-09-05 00:11:13.230 242976 DEBUG oslo_concurrency.processutils [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] CMD "iscsiadm -m session" returned: 21 in 0.006s execute /usr/lib/python2.7/site-packages/oslo_concurrency/processutils.py:385
2017-09-05 00:11:13.230 242976 DEBUG oslo.privsep.daemon [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] privsep: reply[110782256]: (4, ('', 'iscsiadm: No active sessions.\n')) loop /usr/lib/python2.7/site-packages/oslo_privsep/daemon.py:456
2017-09-05 00:11:13.231 120862 DEBUG os_brick.initiator.connectors.iscsi [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] iscsiadm ('-m', 'session'): stdout= stderr=iscsiadm: No active sessions.
 _run_iscsiadm_bare /usr/lib/python2.7/site-packages/os_brick/initiator/connectors/iscsi.py:1077
2017-09-05 00:11:13.231 120862 DEBUG os_brick.initiator.connectors.iscsi [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] iscsi session list stdout= stderr=iscsiadm: No active sessions.
 _run_iscsi_session /usr/lib/python2.7/site-packages/os_brick/initiator/connectors/iscsi.py:1066
2017-09-05 00:11:13.232 120862 WARNING os_brick.initiator.connectors.iscsi [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] Couldn't find iscsi sessions because iscsiadm err: iscsiadm: No active sessions.
: VolumeDeviceNotFound: Volume device not found at .
2017-09-05 00:11:13.232 120862 DEBUG os_brick.initiator.connectors.iscsi [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] Resulting device map defaultdict(<function <lambda> at 0x6a1bde8>, {}) _get_connection_devices /usr/lib/python2.7/site-packages/os_brick/initiator/connectors/iscsi.py:812
2017-09-05 00:11:13.232 120862 DEBUG os_brick.initiator.connectors.iscsi [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] Disconnecting from: [] _disconnect_connection /usr/lib/python2.7/site-packages/os_brick/initiator/connectors/iscsi.py:1054
2017-09-05 00:11:13.233 120862 DEBUG oslo_concurrency.lockutils [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] Lock "connect_volume" released by "os_brick.initiator.connectors.iscsi.connect_volume" :: held 6.479s inner /usr/lib/python2.7/site-packages/oslo_concurrency/lockutils.py:282
2017-09-05 00:11:13.233 120862 DEBUG os_brick.initiator.connectors.iscsi [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] <== connect_volume: exception (6480ms) VolumeDeviceNotFound(u'Volume device not found at .',) trace_logging_wrapper /usr/lib/python2.7/site-packages/os_brick/utils.py:156
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server [req-4fad01c1-20ff-47ee-9065-5a2d4d2c3248 f1991001fc504cb78e1343b326ae4906 b5f0878198214837b753d315cc16ac18 - default default] Exception during message handling: VolumeDeviceNotFound: Volume device not found at .
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server Traceback (most recent call last):
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 160, in _process_incoming
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     res = self.dispatcher.dispatch(message)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 213, in dispatch
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     return self._do_dispatch(endpoint, method, ctxt, args)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 183, in _do_dispatch
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     result = func(ctxt, **new_args)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/cinder/backup/manager.py", line 358, in create_backup
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     self._update_backup_error(backup, six.text_type(err))
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     self.force_reraise()
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     six.reraise(self.type_, self.value, self.tb)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/cinder/backup/manager.py", line 347, in create_backup
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     updates = self._run_backup(context, backup, volume)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/cinder/backup/manager.py", line 396, in _run_backup
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     backup_device.is_snapshot)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/cinder/backup/manager.py", line 882, in _attach_device
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     return self._attach_volume(ctxt, backup_device, properties)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/cinder/backup/manager.py", line 904, in _attach_volume
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     {'volume_id', volume.id})
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     self.force_reraise()
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     six.reraise(self.type_, self.value, self.tb)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/cinder/backup/manager.py", line 893, in _attach_volume
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     return self._connect_device(conn)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/cinder/backup/manager.py", line 934, in _connect_device
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     vol_handle = connector.connect_volume(conn['data'])
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/os_brick/utils.py", line 150, in trace_logging_wrapper
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     result = f(*args, **kwargs)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_concurrency/lockutils.py", line 271, in inner
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     return f(*args, **kwargs)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/os_brick/initiator/connectors/iscsi.py", line 506, in connect_volume
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     self._cleanup_connection(connection_properties, force=True)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 220, in __exit__
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     self.force_reraise()
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 196, in force_reraise
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     six.reraise(self.type_, self.value, self.tb)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/os_brick/initiator/connectors/iscsi.py", line 500, in connect_volume
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     return self._connect_single_volume(connection_properties)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/os_brick/utils.py", line 61, in _wrapper
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     return r.call(f, *args, **kwargs)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/retrying.py", line 229, in call
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     raise attempt.get()
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/retrying.py", line 261, in get
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     six.reraise(self.value[0], self.value[1], self.value[2])
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/retrying.py", line 217, in call
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     attempt = Attempt(fn(*args, **kwargs), attempt_number, False)
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server   File "/usr/lib/python2.7/site-packages/os_brick/initiator/connectors/iscsi.py", line 575, in _connect_single_volume
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server     raise exception.VolumeDeviceNotFound(device='')
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server VolumeDeviceNotFound: Volume device not found at .
2017-09-05 00:11:14.941 120862 ERROR oslo_messaging.rpc.server