fix: introduce ValidateFailoverReservationIntent to silence noisy filter_external_customer errors on failover validation

api/external/nova/messages.go

@@ -241,6 +241,10 @@ const (
 	ReserveForCommittedResourceIntent v1alpha1.SchedulingIntent = "reserve_for_committed_resource"
 	// CapacityProbeIntent indicates that the request is a synthetic capacity probe (not a real VM placement).
 	CapacityProbeIntent v1alpha1.SchedulingIntent = "capacity_probe"
+	// ValidateFailoverReservationIntent indicates that cortex is validating whether a VM
+	// can use a specific failover reservation host. Uses EvacuateIntent semantics in
+	// filter_has_enough_capacity to unlock reservation resources for the VM.
+	ValidateFailoverReservationIntent v1alpha1.SchedulingIntent = "validate_failover_reservation"
 
 	// HintKeyResourceGroup is the scheduler hint key used to pass the resource group
 	// (e.g., flavor group name) for failover reservation scheduling.
@@ -289,6 +293,9 @@ func (req ExternalSchedulerRequest) GetIntent() (v1alpha1.SchedulingIntent, erro
 	// Used by cortex capacity probe controller
 	case "capacity_probe":
 		return CapacityProbeIntent, nil
+	// Used by cortex failover reservation controller (host validation check)
+	case "validate_failover_reservation":
+		return ValidateFailoverReservationIntent, nil
 	default:
 		return CreateIntent, nil
 	}

internal/scheduling/nova/e2e_checks.go

@@ -340,6 +340,26 @@ func randomRequest(dc datacenter, seed int) api.ExternalSchedulerRequest {
 		Hosts:   hosts,
 		Weights: weights,
 	}
+	// Synthesize image properties from flavor extra specs so filter_image_properties
+	// can determine the hypervisor type. Mirrors imagePropertiesFromFlavor in reservation_scheduling.go.
+	switch strings.ToLower(extraSpecs["capabilities:hypervisor_type"]) {
+	case "qemu", "ch":
+		request.Spec.Data.Image = api.NovaObject[api.NovaImageMeta]{
+			Data: api.NovaImageMeta{
+				Properties: api.NovaObject[map[string]any]{
+					Data: map[string]any{"img_hv_type": string(api.NovaImageMetaHVTypeKVM)},
+				},
+			},
+		}
+	case "vmware vcenter server":
+		request.Spec.Data.Image = api.NovaObject[api.NovaImageMeta]{
+			Data: api.NovaImageMeta{
+				Properties: api.NovaObject[map[string]any]{
+					Data: map[string]any{"hypervisor_type": string(api.NovaImageMetaHVTypeVMware)},
+				},
+			},
+		}
+	}
 	// Force to use the pipeline with all filters enabled for kvm flavors.
 	hvType, err := request.GetHypervisorType()
 	if err != nil {

internal/scheduling/nova/plugins/filters/filter_external_customer.go

@@ -43,6 +43,7 @@ func (s *FilterExternalCustomerStep) Run(traceLog logr.Logger, request api.Exter
 	if intent, err := request.GetIntent(); err == nil && slices.Contains([]v1alpha1.SchedulingIntent{
 		api.ReserveForFailoverIntent,
 		api.ReuseFailoverReservationIntent,
+		api.ValidateFailoverReservationIntent,
 		api.CapacityProbeIntent,
 	}, intent) {
 		traceLog.V(1).Info("skipping external customer filter for non-placement intent", "intent", intent)

internal/scheduling/nova/plugins/filters/filter_external_customer_test.go

@@ -380,6 +380,27 @@ func TestFilterExternalCustomerStep_Run(t *testing.T) {
 			expectedHosts: []string{"host1", "host3"},
 			filteredHosts: []string{},
 		},
+		{
+			name: "ValidateFailoverReservationIntent - skips filter, all hosts pass (no domain_name hint)",
+			opts: FilterExternalCustomerStepOpts{
+				CustomerDomainNamePrefixes: []string{"ext-"},
+			},
+			request: api.ExternalSchedulerRequest{
+				Spec: api.NovaObject[api.NovaSpec]{
+					Data: api.NovaSpec{
+						SchedulerHints: map[string]any{
+							"_nova_check_type": string(api.ValidateFailoverReservationIntent),
+						},
+					},
+				},
+				Hosts: []api.ExternalSchedulerHost{
+					{ComputeHost: "host1"},
+					{ComputeHost: "host3"},
+				},
+			},
+			expectedHosts: []string{"host1", "host3"},
+			filteredHosts: []string{},
+		},
 		{
 			name: "ReserveForCommittedResourceIntent - domain filter applies (no domain_name hint → all hosts pass)",
 			opts: FilterExternalCustomerStepOpts{

internal/scheduling/nova/plugins/filters/filter_has_enough_capacity.go

@@ -187,7 +187,7 @@ func (s *FilterHasEnoughCapacity) Run(traceLog logr.Logger, request api.External
 				intent, err := request.GetIntent()
 				if err == nil {
 					switch intent {
-					case api.EvacuateIntent:
+					case api.EvacuateIntent, api.ValidateFailoverReservationIntent:
 						if reservation.Status.FailoverReservation != nil {
 							if _, contained := reservation.Status.FailoverReservation.Allocations[request.Spec.Data.InstanceUUID]; contained {
 								traceLog.V(1).Info("unlocking resources reserved by failover reservation for VM in allocations (evacuation)",

internal/scheduling/nova/plugins/filters/filter_quota_enforcement.go

@@ -92,7 +92,7 @@ func (s *FilterQuotaEnforcement) Run(traceLog logr.Logger, request api.ExternalS
 			traceLog.V(1).Info("skipping quota enforcement for non-consuming intent", "intent", intent)
 			QuotaEnforcementMetricsSingleton.RecordDecision(mode, "accept_skipped_intent_migration", "", "", "")
 			return result, nil
-		case api.ReserveForFailoverIntent, api.ReuseFailoverReservationIntent:
+		case api.ReserveForFailoverIntent, api.ReuseFailoverReservationIntent, api.ValidateFailoverReservationIntent:
 			traceLog.V(1).Info("skipping quota enforcement for failover reservation intent")
 			QuotaEnforcementMetricsSingleton.RecordDecision(mode, "accept_skipped_intent_internal", "", "", "")
 			return result, nil

internal/scheduling/reservations/failover/reservation_scheduling.go

@@ -257,7 +257,7 @@ func (c *FailoverReservationController) validateVMViaSchedulerEvacuation(
 		IgnoreHosts:      []string{vm.CurrentHypervisor},
 		Pipeline:         inferFailoverPipeline(flavorExtraSpecs),
 		AvailabilityZone: vm.AvailabilityZone,
-		SchedulerHints:   map[string]any{"_nova_check_type": string(api.EvacuateIntent)},
+		SchedulerHints:   map[string]any{"_nova_check_type": string(api.ValidateFailoverReservationIntent)},
 		ImageProperties:  imagePropertiesFromFlavor(flavorExtraSpecs),
 	}