feat: make planner use DGD Scaling Adapters (#4825)

Signed-off-by: Julien Mancuso <jmancuso@nvidia.com>

components/src/dynamo/planner/kube.py

@@ -78,11 +78,48 @@ class KubernetesAPI:
                 )
             raise
 
-    def update_graph_replicas(
-        self, graph_deployment_name: str, component_name: str, replicas: int
+    def update_service_replicas(
+        self, graph_deployment_name: str, service_name: str, replicas: int
+    ) -> None:
+        """
+        Update replicas for a service using Scale subresource when DGDSA exists.
+        Falls back to DGD patch for backward compatibility with older operators.
+
+        Args:
+            graph_deployment_name: Name of the DynamoGraphDeployment
+            service_name: Name of the service in DGD.spec.services
+            replicas: Desired number of replicas
+        """
+        # DGDSA naming convention: <dgd-name>-<lowercase-service-name>
+        adapter_name = f"{graph_deployment_name}-{service_name.lower()}"
+
+        try:
+            # Try to scale via DGDSA Scale subresource
+            self.custom_api.patch_namespaced_custom_object_scale(
+                group="nvidia.com",
+                version="v1alpha1",
+                namespace=self.current_namespace,
+                plural="dynamographdeploymentscalingadapters",
+                name=adapter_name,
+                body={"spec": {"replicas": replicas}},
+            )
+            logger.info(f"Scaled DGDSA {adapter_name} to {replicas} replicas")
+
+        except client.ApiException as e:
+            if e.status == 404:
+                # DGDSA doesn't exist - fall back to DGD patch (old operator)
+                logger.info(
+                    f"DGDSA {adapter_name} not found, falling back to DGD update"
+                )
+                self._update_dgd_replicas(graph_deployment_name, service_name, replicas)
+            else:
+                raise
+
+    def _update_dgd_replicas(
+        self, graph_deployment_name: str, service_name: str, replicas: int
     ) -> None:
-        """Update the replicas count for a component in a DynamoGraphDeployment"""
-        patch = {"spec": {"services": {component_name: {"replicas": replicas}}}}
+        """Update replicas directly in DGD (fallback for old operators)"""
+        patch = {"spec": {"services": {service_name: {"replicas": replicas}}}}
         self.custom_api.patch_namespaced_custom_object(
             group="nvidia.com",
             version="v1alpha1",
@@ -91,6 +128,20 @@ class KubernetesAPI:
             name=graph_deployment_name,
             body=patch,
         )
+        logger.info(
+            f"Updated DGD {graph_deployment_name} service {service_name} to {replicas} replicas"
+        )
+
+    def update_graph_replicas(
+        self, graph_deployment_name: str, component_name: str, replicas: int
+    ) -> None:
+        """
+        Update replicas for a service. Now uses DGDSA when available.
+
+        Deprecated: Use update_service_replicas() instead for clarity.
+        This method is kept for backward compatibility.
+        """
+        self.update_service_replicas(graph_deployment_name, component_name, replicas)
 
     def is_deployment_ready(self, deployment: dict) -> bool:
         """Check if a graph deployment is ready"""

deploy/cloud/helm/platform/components/operator/templates/planner.yaml

@@ -39,6 +39,9 @@ rules:
 - apiGroups: ["nvidia.com"]
   resources: ["dynamocomponentdeployments", "dynamographdeployments"]
   verbs: ["get", "list", "create", "update", "patch"]
+- apiGroups: ["nvidia.com"]
+  resources: ["dynamographdeploymentscalingadapters/scale"]
+  verbs: ["patch"]
 ---
 apiVersion: rbac.authorization.k8s.io/v1
 kind: RoleBinding
@@ -68,4 +71,7 @@ rules:
 - apiGroups: ["nvidia.com"]
   resources: ["dynamocomponentdeployments", "dynamographdeployments"]
   verbs: ["get", "list", "create", "update", "patch"]
+- apiGroups: ["nvidia.com"]
+  resources: ["dynamographdeploymentscalingadapters/scale"]
+  verbs: ["patch"]
 {{- end }}

tests/planner/unit/kube.py

@@ -76,11 +76,87 @@ def test_get_graph_deployment_from_name(k8s_api, mock_custom_api):
     )
 
 
-def test_update_graph_replicas(k8s_api, mock_custom_api):
+def test_update_service_replicas_uses_dgdsa_scale(k8s_api, mock_custom_api):
+    """Test that update_service_replicas uses DGDSA Scale API when available"""
+    mock_custom_api.patch_namespaced_custom_object_scale.return_value = None
+
+    k8s_api.update_service_replicas("test-deployment", "Frontend", 3)
+
+    # Should use Scale subresource with lowercase adapter name
+    mock_custom_api.patch_namespaced_custom_object_scale.assert_called_once_with(
+        group="nvidia.com",
+        version="v1alpha1",
+        namespace=k8s_api.current_namespace,
+        plural="dynamographdeploymentscalingadapters",
+        name="test-deployment-frontend",  # lowercase service name
+        body={"spec": {"replicas": 3}},
+    )
+    # Should NOT fall back to DGD patch
+    mock_custom_api.patch_namespaced_custom_object.assert_not_called()
+
+
+def test_update_service_replicas_fallback_to_dgd(k8s_api, mock_custom_api):
+    """Test that update_service_replicas falls back to DGD when DGDSA not found"""
+    # DGDSA doesn't exist (404)
+    mock_custom_api.patch_namespaced_custom_object_scale.side_effect = (
+        client.ApiException(status=404)
+    )
     mock_custom_api.patch_namespaced_custom_object.return_value = None
 
+    k8s_api.update_service_replicas("test-deployment", "test-component", 1)
+
+    # Should have tried DGDSA first
+    mock_custom_api.patch_namespaced_custom_object_scale.assert_called_once()
+
+    # Should fall back to DGD patch
+    mock_custom_api.patch_namespaced_custom_object.assert_called_once_with(
+        group="nvidia.com",
+        version="v1alpha1",
+        namespace=k8s_api.current_namespace,
+        plural="dynamographdeployments",
+        name="test-deployment",
+        body={"spec": {"services": {"test-component": {"replicas": 1}}}},
+    )
+
+
+def test_update_service_replicas_propagates_other_errors(k8s_api, mock_custom_api):
+    """Test that update_service_replicas propagates non-404 errors"""
+    mock_custom_api.patch_namespaced_custom_object_scale.side_effect = (
+        client.ApiException(status=500, reason="Internal Server Error")
+    )
+
+    with pytest.raises(client.ApiException) as exc_info:
+        k8s_api.update_service_replicas("test-deployment", "test-component", 1)
+
+    assert exc_info.value.status == 500
+    # Should NOT fall back to DGD
+    mock_custom_api.patch_namespaced_custom_object.assert_not_called()
+
+
+def test_update_graph_replicas_calls_update_service_replicas(k8s_api, mock_custom_api):
+    """Test that deprecated update_graph_replicas calls update_service_replicas"""
+    mock_custom_api.patch_namespaced_custom_object_scale.return_value = None
+
+    # Use the deprecated method
     k8s_api.update_graph_replicas("test-deployment", "test-component", 1)
 
+    # Should delegate to update_service_replicas which uses Scale API
+    mock_custom_api.patch_namespaced_custom_object_scale.assert_called_once_with(
+        group="nvidia.com",
+        version="v1alpha1",
+        namespace=k8s_api.current_namespace,
+        plural="dynamographdeploymentscalingadapters",
+        name="test-deployment-test-component",
+        body={"spec": {"replicas": 1}},
+    )
+
+
+def test_update_dgd_replicas_directly(k8s_api, mock_custom_api):
+    """Test the internal _update_dgd_replicas method"""
+    mock_custom_api.patch_namespaced_custom_object.return_value = None
+
+    k8s_api._update_dgd_replicas("test-deployment", "test-component", 1)
+
     mock_custom_api.patch_namespaced_custom_object.assert_called_once_with(
         group="nvidia.com",
         version="v1alpha1",