From 52d97807ca11a8f29c648e29606326c0d9a0054e Mon Sep 17 00:00:00 2001
From: Simon Dodsley <simon@purestorage.com>
Date: Tue, 15 Feb 2022 23:45:48 -0500
Subject: [PATCH] PureStorage FlashArray: Add active/active replication

This patch adds support for active/active replication in the
FlashArray driver.

failover_host has been split into two parts (failover and
failover_completed) to allow all nodes in a cluster to properly
switch between primary and secondary backends after a succesful
failover or failback procedure.

Change-Id: I94e9c1106d4be0049b98ec7131ec88c9f9a32588
---
 cinder/tests/unit/volume/drivers/test_pure.py |  6 ++--
 cinder/volume/drivers/pure.py                 | 31 ++++++++++++++++---
 .../pure_aa_replication-e3f5f6666f0b0c43.yaml |  6 ++++
 3 files changed, 35 insertions(+), 8 deletions(-)
 create mode 100644 releasenotes/notes/pure_aa_replication-e3f5f6666f0b0c43.yaml

diff --git a/cinder/tests/unit/volume/drivers/test_pure.py b/cinder/tests/unit/volume/drivers/test_pure.py
index 33b2485519e..5126339baaa 100644
--- a/cinder/tests/unit/volume/drivers/test_pure.py
+++ b/cinder/tests/unit/volume/drivers/test_pure.py
@@ -2881,7 +2881,7 @@ class PureBaseVolumeDriverTestCase(PureBaseSharedDriverTestCase):
         array2.get_volume.return_value = REPLICATED_VOLUME_SNAPS
 
         context = mock.MagicMock()
-        new_active_id, volume_updates, __ = self.driver.failover_host(
+        new_active_id, volume_updates, __ = self.driver.failover(
             context,
             REPLICATED_VOLUME_OBJS,
             None,
@@ -2959,7 +2959,7 @@ class PureBaseVolumeDriverTestCase(PureBaseSharedDriverTestCase):
             {"name": sync_replicated_vol_name}
         ]
 
-        new_active_id, volume_updates, __ = self.driver.failover_host(
+        new_active_id, volume_updates, __ = self.driver.failover(
             context,
             [
                 not_replicated_vol,
@@ -3022,7 +3022,7 @@ class PureBaseVolumeDriverTestCase(PureBaseSharedDriverTestCase):
              mock_get_array,
              array2.get_volume,
              self.async_array2.copy_volume],
-            self.driver.failover_host,
+            self.driver.failover,
             mock.Mock(), REPLICATED_VOLUME_OBJS, None
         )
 
diff --git a/cinder/volume/drivers/pure.py b/cinder/volume/drivers/pure.py
index f56fcf5a08d..c4c815e760f 100644
--- a/cinder/volume/drivers/pure.py
+++ b/cinder/volume/drivers/pure.py
@@ -1929,6 +1929,31 @@ class PureBaseVolumeDriver(san.SanDriver):
 
     @pure_driver_debug_trace
     def failover_host(self, context, volumes, secondary_id=None, groups=None):
+        """Failover to replication target.
+
+        This function combines calls to failover() and failover_completed() to
+        perform failover when Active/Active is not enabled.
+        """
+        active_backend_id, volume_update_list, group_update_list = (
+            self.failover(context, volumes, secondary_id, groups))
+        self.failover_completed(context, secondary_id)
+        return active_backend_id, volume_update_list, group_update_list
+
+    @pure_driver_debug_trace
+    def failover_completed(self, context, secondary_id=None):
+        """Failover to replication target."""
+        LOG.info('Driver failover completion started.')
+        if secondary_id == 'default':
+            self._swap_replication_state(self._get_current_array(),
+                                         self._failed_over_primary_array,
+                                         failback=True)
+        else:
+            self._swap_replication_state(self._get_current_array(),
+                                         self._find_sync_failover_target())
+        LOG.info('Driver failover completion completed.')
+
+    @pure_driver_debug_trace
+    def failover(self, context, volumes, secondary_id=None, groups=None):
         """Failover backend to a secondary array
 
         This action will not affect the original volumes in any
@@ -1964,9 +1989,6 @@ class PureBaseVolumeDriver(san.SanDriver):
                                 'status': 'error',
                             }
                         })
-                self._swap_replication_state(current_array,
-                                             self._failed_over_primary_array,
-                                             failback=True)
                 return secondary_id, model_updates, []
             else:
                 msg = _('Unable to failback to "default", this can only be '
@@ -2037,7 +2059,6 @@ class PureBaseVolumeDriver(san.SanDriver):
             model_updates = self._sync_failover_host(volumes, secondary_array)
 
         current_array = self._get_current_array()
-        self._swap_replication_state(current_array, secondary_array)
 
         return secondary_array.backend_id, model_updates, []
 
@@ -2097,7 +2118,7 @@ class PureBaseVolumeDriver(san.SanDriver):
             if secondary_array in self._uniform_active_cluster_target_arrays:
                 self._uniform_active_cluster_target_arrays.remove(
                     secondary_array)
-            current_array.unform = True
+            current_array.uniform = True
             self._uniform_active_cluster_target_arrays.append(current_array)
 
         self._set_current_array(secondary_array)
diff --git a/releasenotes/notes/pure_aa_replication-e3f5f6666f0b0c43.yaml b/releasenotes/notes/pure_aa_replication-e3f5f6666f0b0c43.yaml
new file mode 100644
index 00000000000..2c7a2ca7277
--- /dev/null
+++ b/releasenotes/notes/pure_aa_replication-e3f5f6666f0b0c43.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Pure Storage FlashArray driver: Enabled support for Active/Active
+    replication for the FlashArray driver. This allows users to configure
+    FlashArray backends in clustered environments.