diff --git a/pkg/promlib/admission_handler.go b/pkg/promlib/admission_handler.go
index 4cfa68b1d53..fb8511373b5 100644
--- a/pkg/promlib/admission_handler.go
+++ b/pkg/promlib/admission_handler.go
@@ -48,8 +48,8 @@ func (s *Service) MutateAdmission(ctx context.Context, req *backend.AdmissionReq
 	default:
 		return getBadRequest(fmt.Sprintf("expected apiVersion: v0alpha1, found: %s", settings.APIVersion)), nil
 	}
-	if settings.URL != "" {
-		return getBadRequest("unsupported URL value"), nil
+	if settings.URL == "" {
+		return getBadRequest("missing URL value"), nil
 	}
 
 	pb, err := backend.DataSourceInstanceSettingsToProtoBytes(settings)
diff --git a/pkg/tsdb/graphite/admission_handler.go b/pkg/tsdb/graphite/admission_handler.go
index 829324d844b..8580c6ed1d3 100644
--- a/pkg/tsdb/graphite/admission_handler.go
+++ b/pkg/tsdb/graphite/admission_handler.go
@@ -48,8 +48,8 @@ func (s *Service) MutateAdmission(ctx context.Context, req *backend.AdmissionReq
 	default:
 		return getBadRequest(fmt.Sprintf("expected apiVersion: v0alpha1, found: %s", settings.APIVersion)), nil
 	}
-	if settings.URL != "" {
-		return getBadRequest("unsupported URL value"), nil
+	if settings.URL == "" {
+		return getBadRequest("missing URL value"), nil
 	}
 
 	pb, err := backend.DataSourceInstanceSettingsToProtoBytes(settings)
diff --git a/pkg/tsdb/prometheus/prometheus.go b/pkg/tsdb/prometheus/prometheus.go
index ef4e1df3105..123e0689103 100644
--- a/pkg/tsdb/prometheus/prometheus.go
+++ b/pkg/tsdb/prometheus/prometheus.go
@@ -45,6 +45,17 @@ func (s *Service) CheckHealth(ctx context.Context, req *backend.CheckHealthReque
 	return s.lib.CheckHealth(ctx, req)
 }
 
+func (s *Service) ValidateAdmission(ctx context.Context, req *backend.AdmissionRequest) (*backend.ValidationResponse, error) {
+	return s.lib.ValidateAdmission(ctx, req)
+}
+
+func (s *Service) MutateAdmission(ctx context.Context, req *backend.AdmissionRequest) (*backend.MutationResponse, error) {
+	return s.lib.MutateAdmission(ctx, req)
+}
+func (s *Service) ConvertObject(ctx context.Context, req *backend.ConversionRequest) (*backend.ConversionResponse, error) {
+	return s.lib.ConvertObject(ctx, req)
+}
+
 func extendClientOpts(ctx context.Context, settings backend.DataSourceInstanceSettings, clientOpts *sdkhttpclient.Options) error {
 	// Set SigV4 service namespace
 	if clientOpts.SigV4 != nil {