Add cinder-manage command to update service_uuid

In some deployments, after an upgrade, we remove the old service
records and create new ones. This leaves the volumes with the
service_uuid pointing to the old (deleted) service and causes an
issue while purging out the deleted service records.
This patch adds a cinder-manage command to update the
service_uuid field of volumes with the following command:

``cinder-manage volume update_service``

The service_uuid of volumes associated with old service_uuid
also gets updated when cinder creates a new service.

Change-Id: I0b13c6351733b8163bcf6e73c939c375493dcba5
(cherry picked from commit edeac132a1)

cinder/cmd/manage.py

@@ -640,6 +640,16 @@ class VolumeCommands(object):
             db.volume_update(ctxt, v['id'],
                              {'host': newhost})
 
+    def update_service(self):
+        """Modify the service uuid associated with a volume.
+
+        In certain upgrade cases, we create new cinder services and delete the
+        records of old ones, however, the volumes created with old service
+        still contain the service uuid of the old services.
+        """
+        ctxt = context.get_admin_context()
+        db.volume_update_all_by_service(ctxt)
+
 
 class ConfigCommands(object):
     """Class for exposing the flags defined by flag_file(s)."""

cinder/db/api.py

@@ -460,6 +460,11 @@ def volume_get_all_by_host(context, host, filters=None):
     return IMPL.volume_get_all_by_host(context, host, filters=filters)
 
 
+def volume_update_all_by_service(context):
+    """Update all volumes associated with an old service."""
+    return IMPL.volume_update_all_by_service(context)
+
+
 def volume_get_all_by_group(context, group_id, filters=None):
     """Get all volumes belonging to a consistency group."""
     return IMPL.volume_get_all_by_group(context, group_id, filters=filters)

cinder/db/sqlalchemy/api.py

@@ -2846,6 +2846,32 @@ def volume_get_all_by_group(context, group_id, filters=None):
     return query.all()
 
 
+@require_admin_context
+@main_context_manager.writer
+def volume_update_all_by_service(context):
+    """Ensure volumes have the correct service_uuid value for their host.
+
+    In some deployment tools, when performing an upgrade, all service records
+    are recreated including c-vol service which gets a new record in the
+    services table, though its host name is constant. Later we then delete the
+    old service record.
+    As a consequence, the volumes have the right host name but the service
+    UUID needs to be updated to the ID of the new service record.
+
+    :param context: context to query under
+    """
+    # Get all cinder-volume services
+    services = service_get_all(context, binary='cinder-volume')
+    for service in services:
+        query = model_query(context, models.Volume)
+        query = query.filter(
+            _filter_host(
+                models.Volume.host, service.host),
+            models.Volume.service_uuid != service.uuid)
+        query.update(
+            {"service_uuid": service.uuid}, synchronize_session=False)
+
+
 @require_context
 @main_context_manager.reader
 def volume_get_all_by_generic_group(context, group_id, filters=None):

cinder/service.py

@@ -42,6 +42,7 @@ profiler_opts = importutils.try_import('osprofiler.opts')
 from cinder.common import constants
 from cinder import context
 from cinder import coordination
+from cinder import db
 from cinder import exception
 from cinder.i18n import _
 from cinder import objects
@@ -366,6 +367,9 @@ class Service(service.Service):
         # If we have updated the service_ref with replication data from
         # the cluster it will be saved.
         service_ref.save()
+        # Update all volumes that are associated with an old service with
+        # the new service uuid
+        db.volume_update_all_by_service(context)
 
     def __getattr__(self, key: str):
         manager = self.__dict__.get('manager', None)

cinder/tests/unit/test_db_api.py

@@ -911,6 +911,42 @@ class DBAPIVolumeTestCase(BaseTest):
                                           filters={'foo': 'bar'})
         self.assertEqual([], vols)
 
+    def test_volume_update_all_by_service(self):
+        volume_service_uuid = '918f24b6-c4c9-48e6-86c6-6871e91f4779'
+        alt_vol_service_uuid = '4b3356a0-31e1-4cec-af1c-07e1e0d7dcf0'
+        service_uuid_1 = 'c7b169f8-8da6-4330-b462-0467069371e2'
+        service_uuid_2 = '38d41b71-2f4e-4d3e-8206-d51ace608bca'
+        host = 'fake_host'
+        alt_host = 'alt_fake_host'
+        binary = 'cinder-volume'
+        # Create 3 volumes with host 'fake_host'
+        for i in range(3):
+            db.volume_create(self.ctxt, {
+                'service_uuid': volume_service_uuid,
+                'host': host,
+                'volume_type_id': fake.VOLUME_TYPE_ID})
+        # Create 2 volumes with host 'alt_fake_host'
+        for i in range(2):
+            db.volume_create(self.ctxt, {
+                'service_uuid': alt_vol_service_uuid,
+                'host': alt_host,
+                'volume_type_id': fake.VOLUME_TYPE_ID})
+        # Create service entry for 'fake_host'
+        utils.create_service(
+            self.ctxt,
+            {'uuid': service_uuid_1, 'host': host, 'binary': binary})
+        # Create service entry for 'alt_fake_host'
+        utils.create_service(
+            self.ctxt,
+            {'uuid': service_uuid_2, 'host': alt_host, 'binary': binary})
+        db.volume_update_all_by_service(self.ctxt)
+        volumes = db.volume_get_all(self.ctxt)
+        for volume in volumes:
+            if volume.host == host:
+                self.assertEqual(service_uuid_1, volume.service_uuid)
+            elif volume.host == alt_host:
+                self.assertEqual(service_uuid_2, volume.service_uuid)
+
     def test_volume_get_all_by_project(self):
         volumes = []
         for i in range(3):

doc/source/cli/cinder-manage.rst

@@ -178,6 +178,15 @@ Delete a volume without first checking that the volume is available.
 Updates the host name of all volumes currently associated with a specified
 host.
 
+``cinder-manage volume update_service``
+
+When upgrading cinder, new service entries are created in the database as the
+existing cinder-volume host(s) are upgraded. In some cases, rows in the
+volumes table keep references to the old service, which can prevent the old
+services from being deleted when the database is purged. This command makes
+sure that all volumes have updated service references for all volumes on all
+cinder-volume hosts.
+
 Cinder Host
 ~~~~~~~~~~~
 

releasenotes/notes/update-service-uuid-f25dbb05efd45d87.yaml

@@ -0,0 +1,15 @@
+---
+features:
+  - |
+    Added a new cinder-manage command to handle the situation where database
+    purges would not complete due to the volumes table holding references to
+    deleted services. The new command makes sure that all volumes have a
+    reference only to the correct service_uuid, which will allow old service
+    records to be purged from the database.
+
+    Command: ``cinder-manage volume update_service``
+  - |
+    When Cinder creates a new cinder-volume service, it now also immediately
+    updates the service_uuid for all volumes associated with that
+    cinder-volume host. In some cases, this was preventing the database purge
+    operation from completing successfully.