Fix: incremental volume backup

The incremental volume backup stopped working after we moved from
cinderclient to SDK[1]. This happened because SDK accepts the
``is_incremental`` parameter[2] rather than the ``incremental`` parameter
which is actually passed in the API request and was previously a valid
parameter for cinderclient.

This patch fixes the issue by passing the ``is_incremental`` field instead
of ``incremental`` from the OSC side which adds the ``incremental`` parameter
in the API request.

Request body after the fix:

'{"backup": {"name": null, "description": null, "volume_id": "<vol-id>",
"force": false, "container": null, "incremental": true}}'

[1] https://review.opendev.org/c/openstack/python-openstackclient/+/889748
[2] 10e5e20fc0/openstack/block_storage/v2/backup.py (L126-L134)

Closes-Bug: #2070080
Change-Id: I89bd3d2751267ec39f4dbd664b7873ab87a9ac6c

openstackclient/tests/unit/volume/v2/test_volume_backup.py

@@ -120,7 +120,7 @@ class TestBackupCreate(TestBackup):
             name=self.new_backup.name,
             description=self.new_backup.description,
             force=True,
-            incremental=True,
+            is_incremental=True,
             snapshot_id=self.new_backup.snapshot_id,
         )
         self.assertEqual(self.columns, columns)
@@ -150,7 +150,7 @@ class TestBackupCreate(TestBackup):
             name=None,
             description=None,
             force=False,
-            incremental=False,
+            is_incremental=False,
             metadata={"foo": "bar", "wow": "much-cool"},
         )
         self.assertEqual(self.columns, columns)
@@ -199,7 +199,7 @@ class TestBackupCreate(TestBackup):
             name=None,
             description=None,
             force=False,
-            incremental=False,
+            is_incremental=False,
             availability_zone="my-az",
         )
         self.assertEqual(self.columns, columns)
@@ -247,7 +247,7 @@ class TestBackupCreate(TestBackup):
             name=None,
             description=self.new_backup.description,
             force=False,
-            incremental=False,
+            is_incremental=False,
         )
         self.assertEqual(self.columns, columns)
         self.assertEqual(self.data, data)

openstackclient/volume/v2/volume_backup.py

@@ -173,7 +173,7 @@ class CreateVolumeBackup(command.ShowOne):
             name=parsed_args.name,
             description=parsed_args.description,
             force=parsed_args.force,
-            incremental=parsed_args.incremental,
+            is_incremental=parsed_args.incremental,
             **kwargs,
         )
         data = utils.get_dict_properties(backup, columns)

releasenotes/notes/fix-backup-incremental-d1c1e6886cf32256.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixed issue with creating incremental volume backup.
+    Previously, ``incremental`` value was not passed in the
+    API request which is now included in the backup
+    create request.