diff --git a/aodh/api/controllers/v2/alarm_rules/gnocchi.py b/aodh/api/controllers/v2/alarm_rules/gnocchi.py
index fafdc02bb..e2b5be52c 100644
--- a/aodh/api/controllers/v2/alarm_rules/gnocchi.py
+++ b/aodh/api/controllers/v2/alarm_rules/gnocchi.py
@@ -34,6 +34,10 @@ GNOCCHI_OPTS = [
                default="service",
                help='Project name of resources creator in Gnocchi. '
                '(For example the Ceilometer project name'),
+    cfg.StrOpt('gnocchi_external_domain_name',
+               default="Default",
+               help='Domain name of resources creator in Gnocchi. '
+               '(For example, default or service_domain'),
 ]
 
 
@@ -139,8 +143,12 @@ class AggregationMetricByResourcesLookupRule(AlarmGnocchiThresholdRule):
     def get_external_project_owner():
         kc = keystone_client.get_client(pecan.request.cfg)
         project_name = pecan.request.cfg.api.gnocchi_external_project_owner
+        domain_name = pecan.request.cfg.api.gnocchi_external_domain_name
+        domains = kc.domains.list(name=domain_name)
         try:
-            project = kc.projects.find(name=project_name)
+            project = kc.projects.find(
+                name=project_name,
+                domain_id=domains[0].id)
             return project.id
         except ka_exceptions.NotFound:
             return None
diff --git a/aodh/tests/functional/api/v2/test_alarm_scenarios.py b/aodh/tests/functional/api/v2/test_alarm_scenarios.py
index 02c04c869..1bbf6d54f 100644
--- a/aodh/tests/functional/api/v2/test_alarm_scenarios.py
+++ b/aodh/tests/functional/api/v2/test_alarm_scenarios.py
@@ -2370,6 +2370,9 @@ class TestAlarmsRuleGnocchi(TestAlarmsBase):
         ]}
 
         ks_client = mock.Mock()
+        ks_client.domains.list.return_value = [mock.Mock(
+            id='<my-uuid>',
+            name='Default')]
         ks_client.projects.find.return_value = mock.Mock(id='<my-uuid>')
         get_client.return_value = ks_client