[Pure Storage] Enable sync repl volume creation during failover

Currently when cinder failover is invoked, due to the primary
storage backend being down, it is not possible, through the
driver, to create a new volume with sync replication
functionality. Non-replicated and async replicated volumes can
be created in this scenario - although not recommended due to
potential issues after failback.

A synchronously replicated volume could be safely created
during failover as the Pure Storage architecture can allow
this to happen. When the failed array is available again, any
new sync replication volumes created during the outage will be
automatically recovered by the backend's own internal systems.

This patch updates the driver to check, during volume creation,
if the backend is in failover mode and then allow sync volumes
to be correctly created, even though the primary array could be
inaccessible. Sync volume attachment will also be allowed to
continue should one of the backend replica pair arrays be down.

Creating different replication volume types have been tested
both failover and failback scenarios in Pure's labs and this
patch has proved to work as expected.

Additionally included is work from abandoned
change I7ed3ebd7fec389870edad0c1cc07ac553854dd8a, which
resolves replication issues in A/A deployments.

Also, fixes bug where a deleted replication pod can cause the
driver to fail on restart.

Closes-Bug: #2035404
Change-Id: I58f0f10b63431896e7532b16b561683cd242e9ee

cinder/tests/unit/volume/drivers/test_pure.py

@@ -1085,6 +1085,48 @@ class PureBaseVolumeDriverTestCase(PureBaseSharedDriverTestCase):
         for update, vol_name in zip(model_updates, vol_names):
             self.assertEqual(vol_name, update['provider_id'])
 
+    @mock.patch(BASE_DRIVER_OBJ + '._swap_replication_state')
+    @mock.patch(BASE_DRIVER_OBJ + '._setup_replicated_pods')
+    @mock.patch(BASE_DRIVER_OBJ + '._generate_replication_retention')
+    @mock.patch(BASE_DRIVER_OBJ + '._setup_replicated_pgroups')
+    def test_do_setup_replicated_sync_rep_need_swap(
+            self,
+            mock_setup_repl_pgroups,
+            mock_generate_replication_retention,
+            mock_setup_pods,
+            mock_swap):
+        """Test do_setup when using replication and active is secondary."""
+        retention = mock.MagicMock()
+        mock_generate_replication_retention.return_value = retention
+        self._setup_mocks_for_replication()
+
+        self.mock_config.safe_get.return_value = [
+            {
+                "backend_id": "foo",
+                "managed_backend_name": None,
+                "san_ip": "1.2.3.4",
+                "api_token": "abc123",
+                "type": "sync",
+            }
+        ]
+        mock_sync_target = mock.MagicMock()
+        mock_sync_target.get.return_value = GET_ARRAY_SECONDARY
+        self.array.get.return_value = GET_ARRAY_PRIMARY
+        self.purestorage_module.FlashArray.side_effect = [self.array,
+                                                          mock_sync_target]
+        self.driver._active_backend_id = 'foo'
+        self.driver.do_setup(None)
+        self.assertEqual(self.array, self.driver._array)
+
+        mock_setup_repl_pgroups.assert_has_calls([
+            mock.call(self.array, [mock_sync_target], 'cinder-group',
+                      REPLICATION_INTERVAL_IN_SEC, retention),
+        ])
+        mock_setup_pods.assert_has_calls([
+            mock.call(self.array, [mock_sync_target], 'cinder-pod')
+        ])
+        mock_swap.assert_called_once_with(self.driver._array, mock_sync_target)
+
     def test_update_provider_info_update_some(self):
         test_vols = [
             self.new_fake_vol(spec={'id': fake.VOLUME_ID},
@@ -3331,10 +3373,13 @@ class PureBaseVolumeDriverTestCase(PureBaseSharedDriverTestCase):
         ]
         self.assertEqual(expected_updates, volume_updates)
 
+    @mock.patch(BASE_DRIVER_OBJ + '._get_secondary')
     @mock.patch(BASE_DRIVER_OBJ + '._get_flasharray')
     @mock.patch(BASE_DRIVER_OBJ + '._find_async_failover_target')
     def test_async_failover_error_propagates(self, mock_find_failover_target,
-                                             mock_get_array):
+                                             mock_get_array,
+                                             mock_get_secondary):
+        mock_get_secondary.return_value = self.async_array2
         mock_find_failover_target.return_value = (
             self.async_array2,
             REPLICATED_PGSNAPS[1]
@@ -3647,9 +3692,6 @@ class PureISCSIDriverTestCase(PureBaseSharedDriverTestCase):
         mock_get_iscsi_ports.assert_called_with(self.array)
         mock_connection.assert_called_with(self.array, vol_name,
                                            ISCSI_CONNECTOR, None, None)
-        self.assert_error_propagates([mock_get_iscsi_ports, mock_connection],
-                                     self.driver.initialize_connection,
-                                     vol, ISCSI_CONNECTOR)
 
     @mock.patch(ISCSI_DRIVER_OBJ + "._get_wwn")
     @mock.patch(ISCSI_DRIVER_OBJ + "._connect")
@@ -3675,9 +3717,6 @@ class PureISCSIDriverTestCase(PureBaseSharedDriverTestCase):
         mock_get_iscsi_ports.assert_called_with(self.array)
         mock_connection.assert_called_with(self.array, vol_name,
                                            ISCSI_CONNECTOR, None, None)
-        self.assert_error_propagates([mock_get_iscsi_ports, mock_connection],
-                                     self.driver.initialize_connection,
-                                     vol, ISCSI_CONNECTOR)
 
     @mock.patch(ISCSI_DRIVER_OBJ + "._get_wwn")
     @mock.patch(ISCSI_DRIVER_OBJ + "._connect")
@@ -3849,10 +3888,6 @@ class PureISCSIDriverTestCase(PureBaseSharedDriverTestCase):
                                            chap_password)
         self.assertDictEqual(result, real_result)
 
-        self.assert_error_propagates([mock_get_iscsi_ports, mock_connection],
-                                     self.driver.initialize_connection,
-                                     vol, ISCSI_CONNECTOR)
-
     @mock.patch(ISCSI_DRIVER_OBJ + "._get_wwn")
     @mock.patch(ISCSI_DRIVER_OBJ + "._connect")
     @mock.patch(ISCSI_DRIVER_OBJ + "._get_target_iscsi_ports")
@@ -4839,12 +4874,6 @@ class PureNVMEDriverTestCase(PureBaseSharedDriverTestCase):
         mock_connection.assert_called_with(
             self.array, vol_name, NVME_CONNECTOR
         )
-        self.assert_error_propagates(
-            [mock_get_nvme_ports, mock_connection],
-            self.driver.initialize_connection,
-            vol,
-            NVME_CONNECTOR,
-        )
 
     @mock.patch(NVME_DRIVER_OBJ + "._get_nguid")
     @mock.patch(NVME_DRIVER_OBJ + "._get_wwn")
@@ -4875,12 +4904,6 @@ class PureNVMEDriverTestCase(PureBaseSharedDriverTestCase):
         mock_connection.assert_called_with(
             self.array, vol_name, NVME_CONNECTOR
         )
-        self.assert_error_propagates(
-            [mock_get_nvme_ports, mock_connection],
-            self.driver.initialize_connection,
-            vol,
-            NVME_CONNECTOR,
-        )
 
     @mock.patch(NVME_DRIVER_OBJ + "._get_nguid")
     @mock.patch(NVME_DRIVER_OBJ + "._get_wwn")

cinder/volume/drivers/pure.py

@@ -198,7 +198,7 @@ def pure_driver_debug_trace(f):
         cls_name = driver.__class__.__name__
         method_name = "%(cls_name)s.%(method)s" % {"cls_name": cls_name,
                                                    "method": f.__name__}
-        backend_name = driver._get_current_array().backend_id
+        backend_name = driver._get_current_array(True).backend_id
         LOG.debug("[%(backend_name)s] Enter %(method_name)s, args=%(args)s,"
                   " kwargs=%(kwargs)s",
                   {
@@ -440,13 +440,10 @@ class PureBaseVolumeDriver(san.SanDriver):
 
         # If we have failed over at some point we need to adjust our current
         # array based on the one that we have failed over to
-        if (self._array is not None and
+        if (self._active_backend_id and
-                self._active_backend_id is not None and
                 self._active_backend_id != self._array.backend_id):
-            for secondary_array in self._replication_target_arrays:
+            secondary_array = self._get_secondary(self._active_backend_id)
-                if secondary_array.backend_id == self._active_backend_id:
             self._swap_replication_state(self._array, secondary_array)
-                    break
 
     def do_setup_trisync(self):
         repl_device = {}
@@ -2281,20 +2278,30 @@ class PureBaseVolumeDriver(san.SanDriver):
         """
         active_backend_id, volume_update_list, group_update_list = (
             self.failover(context, volumes, secondary_id, groups))
-        self.failover_completed(context, secondary_id)
+        self.failover_completed(context, active_backend_id)
         return active_backend_id, volume_update_list, group_update_list
 
     @pure_driver_debug_trace
-    def failover_completed(self, context, secondary_id=None):
+    def failover_completed(self, context, active_backend_id=None):
         """Failover to replication target."""
         LOG.info('Driver failover completion started.')
-        if secondary_id == 'default':
+        current = self._get_current_array()
-            self._swap_replication_state(self._get_current_array(),
+        # This should not happen unless we receive the same RPC message twice
+        if active_backend_id == current.backend_id:
+            LOG.info('No need to switch replication backend, already using it')
+
+        # Manager sets the active_backend to '' when secondary_id was default,
+        # but the driver failover_host method calls us with "default"
+        elif not active_backend_id or active_backend_id == 'default':
+            LOG.info('Failing back to %s', self._failed_over_primary_array)
+            self._swap_replication_state(current,
                                          self._failed_over_primary_array,
                                          failback=True)
         else:
-            self._swap_replication_state(self._get_current_array(),
+            secondary = self._get_secondary(active_backend_id)
-                                         self._find_sync_failover_target())
+            LOG.info('Failing over to %s', secondary.backend_id)
+            self._swap_replication_state(current,
+                                         secondary)
         LOG.info('Driver failover completion completed.')
 
     @pure_driver_debug_trace
@@ -2340,7 +2347,7 @@ class PureBaseVolumeDriver(san.SanDriver):
                         'done after a failover has completed.')
                 raise exception.InvalidReplicationTarget(message=msg)
 
-        current_array = self._get_current_array()
+        current_array = self._get_current_array(True)
         LOG.debug("Failover replication for array %(primary)s to "
                   "%(secondary)s.",
                   {"primary": current_array.backend_id,
@@ -2356,19 +2363,9 @@ class PureBaseVolumeDriver(san.SanDriver):
         secondary_array = None
         pg_snap = None  # used for async only
         if secondary_id:
-            for array in self._replication_target_arrays:
+            secondary_array = self._get_secondary(secondary_id)
-                if array.backend_id == secondary_id:
+            if secondary_array.replication_type in [REPLICATION_TYPE_ASYNC,
-                    secondary_array = array
+                                                    REPLICATION_TYPE_SYNC]:
-                    break
-
-            if not secondary_array:
-                raise exception.InvalidReplicationTarget(
-                    reason=_("Unable to determine secondary_array from"
-                             " supplied secondary: %(secondary)s.") %
-                    {"secondary": secondary_id}
-                )
-
-            if secondary_array.replication_type == REPLICATION_TYPE_ASYNC:
                 pg_snap = self._get_latest_replicated_pg_snap(
                     secondary_array,
                     self._get_current_array().array_name,
@@ -2403,7 +2400,7 @@ class PureBaseVolumeDriver(san.SanDriver):
         elif secondary_array.replication_type == REPLICATION_TYPE_SYNC:
             model_updates = self._sync_failover_host(volumes, secondary_array)
 
-        current_array = self._get_current_array()
+        current_array = self._get_current_array(True)
 
         return secondary_array.backend_id, model_updates, []
 
@@ -2436,6 +2433,7 @@ class PureBaseVolumeDriver(san.SanDriver):
         if failback:
             self._replication_target_arrays.append(current_array)
             self._is_replication_enabled = True
+            self._failed_over_primary_array = None
 
         # If its sync rep then swap the two in their lists since it is a
         # bi-directional setup, if the primary is still OK or comes back
@@ -2730,6 +2728,17 @@ class PureBaseVolumeDriver(san.SanDriver):
 
         return secondary_array, pg_snap
 
+    def _get_secondary(self, secondary_id):
+        for array in self._replication_target_arrays:
+            if array.backend_id == secondary_id:
+                return array
+
+        raise exception.InvalidReplicationTarget(
+            reason=_("Unable to determine secondary_array from"
+                     " supplied secondary: %(secondary)s.") %
+            {"secondary": secondary_id}
+        )
+
     def _find_sync_failover_target(self):
         secondary_array = None
         if not self._active_cluster_target_arrays:
@@ -2766,6 +2775,14 @@ class PureBaseVolumeDriver(san.SanDriver):
 
         # We have to rely on a call that is only available in REST API 1.3
         # therefore we have to create a temporary FlashArray for this.
+        if hasattr(secondary_array, '_request_kwargs'):
+            target_array = self._get_flasharray(
+                secondary_array._target,
+                api_token=secondary_array._api_token,
+                rest_version='1.3',
+                request_kwargs=secondary_array._request_kwargs,
+            )
+        else:
             target_array = self._get_flasharray(
                 secondary_array._target,
                 api_token=secondary_array._api_token,
@@ -2859,13 +2876,15 @@ class PureBaseVolumeDriver(san.SanDriver):
         return wwn.lower()
 
     def _get_current_array(self, init=False):
-        if not init and self._is_active_cluster_enabled:
+        if (not init and
-            for target_array in self._active_cluster_target_arrays:
+                self._is_active_cluster_enabled and
+                not self._failed_over_primary_array):
             try:
+                pod_info = self._array.get_pod(self._replication_pod_name)
+                for target_array in self._active_cluster_target_arrays:
                     LOG.info("Checking target array %s...",
                              target_array.array_name)
                     status_ok = False
-                    pod_info = target_array.get_pod(self._replication_pod_name)
                     for pod_array in pod_info['arrays']:
                         if pod_array['array_id'] == target_array.array_id:
                             if pod_array['status'] == 'online':
@@ -2917,7 +2936,8 @@ class PureISCSIDriver(PureBaseVolumeDriver, san.SanISCSIDriver):
         pure_vol_name = self._get_vol_name(volume)
         target_arrays = [self._get_current_array()]
         if (self._is_vol_in_pod(pure_vol_name) and
-                self._is_active_cluster_enabled):
+                self._is_active_cluster_enabled and
+                not self._failed_over_primary_array):
             target_arrays += self._uniform_active_cluster_target_arrays
 
         chap_username = None
@@ -2928,9 +2948,15 @@ class PureISCSIDriver(PureBaseVolumeDriver, san.SanISCSIDriver):
 
         targets = []
         for array in target_arrays:
+            try:
                 connection = self._connect(array, pure_vol_name, connector,
                                            chap_username, chap_password)
 
+            except purestorage.PureError as err:
+                # Swallow any exception, just warn and continue
+                LOG.warning("self._connect failed with"
+                            " message: %(msg)s", {"msg": err.reason})
+                continue
             target_ports = self._get_target_iscsi_ports(array)
             targets.append({
                 "connection": connection,
@@ -3161,7 +3187,8 @@ class PureFCDriver(PureBaseVolumeDriver, driver.FibreChannelDriver):
         pure_vol_name = self._get_vol_name(volume)
         target_arrays = [self._get_current_array()]
         if (self._is_vol_in_pod(pure_vol_name) and
-                self._is_active_cluster_enabled):
+                self._is_active_cluster_enabled and
+                not self._failed_over_primary_array):
             target_arrays += self._uniform_active_cluster_target_arrays
 
         target_luns = []
@@ -3360,15 +3387,20 @@ class PureNVMEDriver(PureBaseVolumeDriver, driver.BaseVD):
         """Allow connection to connector and return connection info."""
         pure_vol_name = self._get_vol_name(volume)
         target_arrays = [self._get_current_array()]
-        if (
+        if (self._is_vol_in_pod(pure_vol_name) and
-            self._is_vol_in_pod(pure_vol_name)
+                self._is_active_cluster_enabled and
-            and self._is_active_cluster_enabled
+                not self._failed_over_primary_array):
-        ):
             target_arrays += self._uniform_active_cluster_target_arrays
 
         targets = []
         for array in target_arrays:
+            try:
                 connection = self._connect(array, pure_vol_name, connector)
+            except purestorage.PureError as err:
+                # Swallow any exception, just warn and continue
+                LOG.warning("self._connect failed with"
+                            " message: %(msg)s", {"msg": err.reason})
+                continue
             target_ports = self._get_target_nvme_ports(array)
             targets.append(
                 {

releasenotes/notes/pure_failover_sync-86814167598af2f8.yaml

@@ -0,0 +1,11 @@
+---
+features:
+  - |
+    Pure Storage driver: Allow synchronously replicated volumes
+    to be created during a replication failover event. These will
+    remain viable volumes when the replication is failed back to
+    its original state.
+fixes:
+  - |
+    [Pure Storage] `Bug #2035404 <https://bugs.launchpad.net/cinder/+bug/2035404>`_:
+    Fixed issue with missing replication pod causing driver to fail on restart.