Allow scheduling to disabled manila-share host

- Only allow to admin user and with 'only_host' scheduler hint

In all other cases, scheduler will ignore disabled host. Please note,
'disabled' host is up/running(i.e. listening on RPC calls), but
disabled using share service set API.

Closes-bug: #2072552
Change-Id: Iaaa4e274d47cf2eaa0247234f268fdb5ff24461b

doc/source/admin/shared-file-systems-services-manage.rst

@@ -13,4 +13,5 @@ items that have field ``binary`` equal to ``manila-share``. Also, you can
 enable or disable share services using raw API requests. Disabling means that
 share services are excluded from the scheduler cycle and new shares will not
 be placed on the disabled back end. However, shares from this service stay
-available.
+available. With 2024.2 release, admin can schedule share on disabled back end
+using ``only_host`` scheduler hint.

manila/db/api.py

@@ -103,9 +103,10 @@ def service_get_all(context, disabled=None):
     return IMPL.service_get_all(context, disabled)
 
 
-def service_get_all_by_topic(context, topic):
+def service_get_all_by_topic(context, topic, consider_disabled=False):
     """Get all services for a given topic."""
-    return IMPL.service_get_all_by_topic(context, topic)
+    return IMPL.service_get_all_by_topic(context, topic,
+                                         consider_disabled=consider_disabled)
 
 
 def service_get_all_share_sorted(context):

manila/db/sqlalchemy/api.py

@@ -582,12 +582,14 @@ def service_get_all(context, disabled=None):
 
 @require_admin_context
 @context_manager.reader
-def service_get_all_by_topic(context, topic):
+def service_get_all_by_topic(context, topic, consider_disabled=False):
-    return (model_query(
+    query = model_query(
-        context, models.Service, read_deleted="no").
+        context, models.Service, read_deleted="no")
-        filter_by(disabled=False).
+
-        filter_by(topic=topic).
+    if not consider_disabled:
-        all())
+        query = query.filter_by(disabled=False)
+
+    return query.filter_by(topic=topic).all()
 
 
 @require_admin_context

manila/scheduler/drivers/filter.py

@@ -27,6 +27,7 @@ from manila import exception
 from manila.i18n import _
 from manila.message import api as message_api
 from manila.message import message_field
+from manila import policy
 from manila.scheduler.drivers import base
 from manila.scheduler import scheduler_options
 from manila.share import share_types
@@ -240,7 +241,16 @@ class FilterScheduler(base.Scheduler):
 
         # Note: remember, we are using an iterator here. So only
         # traverse this list once.
-        hosts = self.host_manager.get_all_host_states_share(elevated)
+        consider_disabled = False
+        if policy.check_is_host_admin(context) and filter_properties.get(
+                'scheduler_hints', {}).get('only_host'):
+            # Admin user can schedule share on disabled host
+            consider_disabled = True
+
+        hosts = self.host_manager.get_all_host_states_share(
+            elevated,
+            consider_disabled=consider_disabled
+        )
         if not hosts:
             msg = _("There are no hosts to fulfill this "
                     "provisioning request. Are share "

manila/scheduler/host_manager.py

@@ -631,18 +631,23 @@ class HostManager(object):
                   {'service_name': service_name, 'host': host,
                    'cap': capabilities})
 
-    def _update_host_state_map(self, context):
+    def _update_host_state_map(self, context, consider_disabled=False):
-
         # Get resource usage across the available share nodes:
         topic = CONF.share_topic
-        share_services = db.service_get_all_by_topic(context, topic)
+        share_services = db.service_get_all_by_topic(
+            context,
+            topic,
+            consider_disabled=consider_disabled,
+        )
 
         active_hosts = set()
         for service in share_services:
             host = service['host']
 
             # Warn about down services and remove them from host_state_map
-            if not utils.service_is_up(service) or service['disabled']:
+            is_down = not utils.service_is_up(service)
+            is_disabled = (not consider_disabled and service['disabled'])
+            if is_down or is_disabled:
                 LOG.warning("Share service is down. (host: %s).", host)
                 continue
 
@@ -668,7 +673,7 @@ class HostManager(object):
                      "scheduler cache.", {'host': host})
             self.host_state_map.pop(host, None)
 
-    def get_all_host_states_share(self, context):
+    def get_all_host_states_share(self, context, consider_disabled=False):
         """Returns a dict of all the hosts the HostManager knows about.
 
         Each of the consumable resources in HostState are
@@ -678,7 +683,10 @@ class HostManager(object):
           {'192.168.1.100': HostState(), ...}
         """
 
-        self._update_host_state_map(context)
+        self._update_host_state_map(
+            context,
+            consider_disabled=consider_disabled,
+        )
 
         # Build a pool_state map and return that map instead of host_state_map
         all_pools = {}

manila/tests/scheduler/drivers/test_filter.py

@@ -641,6 +641,35 @@ class FilterSchedulerTestCase(test_base.SchedulerTestCase):
                           sched.schedule_create_replica,
                           self.context, request_spec, {})
 
+    @mock.patch('manila.db.service_get_all_by_topic')
+    def test__schedule_share_with_disabled_host(
+            self, _mock_service_get_all_by_topic):
+        sched = fakes.FakeFilterScheduler()
+        sched.host_manager = fakes.FakeHostManager()
+        fake_context = context.RequestContext('user', 'project',
+                                              is_admin=True)
+        fake_type = {'name': 'NFS'}
+        request_spec = {
+            'share_properties': {'project_id': 1, 'size': 1},
+            'share_instance_properties': {},
+            'share_type': fake_type,
+            'share_id': 'fake-id1',
+        }
+        filter_properties = {
+            'scheduler_hints': {'only_host': 'host7#_pool0'}
+        }
+        fakes.mock_host_manager_db_calls(_mock_service_get_all_by_topic,
+                                         disabled=True)
+
+        weighed_host = sched._schedule_share(
+            fake_context, request_spec,
+            filter_properties=filter_properties)
+
+        self.assertIsNotNone(weighed_host)
+        self.assertIsNotNone(weighed_host.obj)
+        self.assertEqual('host7', weighed_host.obj.host.split('#')[0])
+        self.assertTrue(_mock_service_get_all_by_topic.called)
+
     def test_schedule_create_replica(self):
         sched = fakes.FakeFilterScheduler()
         request_spec = fakes.fake_replica_request_spec()

manila/tests/scheduler/fakes.py

@@ -530,6 +530,19 @@ class FakeHostManager(host_manager.HostManager):
                       'storage_protocol': 'GLUSTERFS',
                       'vendor_name': 'Dummy',
                       },
+            'host7': {'total_capacity_gb': 'unknown',
+                      'free_capacity_gb': 'unknown',
+                      'allocated_capacity_gb': 1548,
+                      'thin_provisioning': False,
+                      'reserved_percentage': 5,
+                      'reserved_snapshot_percentage': 2,
+                      'reserved_share_extend_percentage': 5,
+                      'snapshot_support': True,
+                      'create_share_from_snapshot_support': True,
+                      'timestamp': None,
+                      'storage_protocol': 'NFS_CIFS',
+                      'vendor_name': 'Dummy',
+                      },
         }
 
 
@@ -565,6 +578,9 @@ def mock_host_manager_db_calls(mock_obj, disabled=None):
         dict(id=6, host='host6', topic='share', disabled=False,
              availability_zone=FAKE_AZ_4, availability_zone_id=FAKE_AZ_4['id'],
              updated_at=timeutils.utcnow()),
+        dict(id=7, host='host7', topic='share', disabled=True,
+             availability_zone=FAKE_AZ_4, availability_zone_id=FAKE_AZ_4['id'],
+             updated_at=timeutils.utcnow()),
     ]
     if disabled is None:
         mock_obj.return_value = services

manila/tests/scheduler/test_host_manager.py

@@ -169,7 +169,7 @@ class HostManagerTestCase(test.TestCase):
                 host = share_node['host']
                 self.assertEqual(share_node, host_state_map[host].service)
             db.service_get_all_by_topic.assert_called_once_with(
-                fake_context, topic)
+                fake_context, topic, consider_disabled=False)
 
     def test_get_pools_no_pools(self):
         fake_context = context.RequestContext('user', 'project')

manila/tests/scheduler/weighers/test_capacity.py

@@ -54,7 +54,7 @@ class CapacityWeigherTestCase(test.TestCase):
                                          disabled=disabled)
         host_states = self.host_manager.get_all_host_states_share(ctxt)
         _mock_service_get_all_by_topic.assert_called_once_with(
-            ctxt, CONF.share_topic)
+            ctxt, CONF.share_topic, consider_disabled=False)
         return host_states
 
     # NOTE(xyang): If thin_provisioning = True and

manila/tests/scheduler/weighers/test_netapp_aiq.py

@@ -262,7 +262,7 @@ class NetAppAIQWeigherTestCase(test.TestCase):
                                          disabled=disabled)
         host_states = self.host_manager.get_all_host_states_share(ctxt)
         _mock_service_get_all_by_topic.assert_called_once_with(
-            ctxt, CONF.share_topic)
+            ctxt, CONF.share_topic, consider_disabled=False)
         return host_states
 
     def test_weigh_objects_netapp_only(self):

manila/tests/scheduler/weighers/test_pool.py

@@ -80,7 +80,7 @@ class PoolWeigherTestCase(test.TestCase):
         ctxt = context.get_admin_context()
         host_states = self.host_manager.get_all_host_states_share(ctxt)
         db_api.IMPL.service_get_all_by_topic.assert_called_once_with(
-            ctxt, CONF.share_topic)
+            ctxt, CONF.share_topic, consider_disabled=False)
         return host_states
 
     def test_no_server_pool_mapping(self):

releasenotes/notes/bug-2072552-allow-scheduling-to-disabled-host-82c93468ec322256.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Manila now allows OpenStack administrators to schedule shares on hosts
+    that are currently running and marked as under maintenance (`disabled`)
+    through the `only_host` scheduler hint. For more details, please refer to
+    `launchpad bug 2072552 <https://bugs.launchpad.net/manila/+bug/2072552>`_