Add toggle for nova input host safety measure

Author: PhilippMatthes

cmd/main.go

@@ -322,7 +322,8 @@ func main() {
 			setupLog.Error(err, "unable to create controller", "controller", "nova FilterWeigherPipelineController")
 			os.Exit(1)
 		}
-		nova.NewAPI(filterWeigherController).Init(mux)
+		novaAPIConfig := conf.GetConfigOrDie[nova.HTTPAPIConfig]()
+		nova.NewAPI(novaAPIConfig, filterWeigherController).Init(mux)
 
 		// Initialize commitments API for LIQUID interface
 		commitmentsAPI := commitments.NewAPI(multiclusterClient)

helm/bundles/cortex-nova/values.yaml

@@ -138,6 +138,9 @@ cortex-scheduling-controllers:
       - failover-reservations-controller
     enabledTasks:
       - nova-history-cleanup-task
+    # If true, the external scheduler API will limit the list of hosts in its
+    # response to those included in the scheduling request.
+    novaLimitHostsToRequest: true
     # CommittedResourceFlavorGroupPipelines maps flavor group IDs to pipeline names for CR reservations
     # This allows different scheduling strategies per flavor group (e.g., HANA vs GP)
     committedResourceFlavorGroupPipelines:

internal/scheduling/nova/external_scheduler_api.go

@@ -34,15 +34,23 @@ type HTTPAPI interface {
 	Init(*http.ServeMux)
 }
 
+type HTTPAPIConfig struct {
+	// NovaLimitHostsToRequest, if true, will filter the Nova scheduler response
+	// to only include hosts that were in the original request.
+	NovaLimitHostsToRequest bool `json:"novaLimitHostsToRequest,omitempty"`
+}
+
 type httpAPI struct {
 	monitor  scheduling.APIMonitor
 	delegate HTTPAPIDelegate
+	config   HTTPAPIConfig
 }
 
-func NewAPI(delegate HTTPAPIDelegate) HTTPAPI {
+func NewAPI(config HTTPAPIConfig, delegate HTTPAPIDelegate) HTTPAPI {
 	return &httpAPI{
 		monitor:  scheduling.NewSchedulerMonitor(),
 		delegate: delegate,
+		config:   config,
 	}
 }
 
@@ -222,7 +230,11 @@ func (httpAPI *httpAPI) NovaExternalScheduler(w http.ResponseWriter, r *http.Req
 		return
 	}
 	hosts := decision.Status.Result.OrderedHosts
-	hosts = limitHostsToRequest(requestData, hosts)
+	if httpAPI.config.NovaLimitHostsToRequest {
+		hosts = limitHostsToRequest(requestData, hosts)
+		slog.Info("limited hosts to request",
+			"hosts", hosts, "originalHosts", decision.Status.Result.OrderedHosts)
+	}
 	response := api.ExternalSchedulerResponse{Hosts: hosts}
 	w.Header().Set("Content-Type", "application/json")
 	if err = json.NewEncoder(w).Encode(response); err != nil {

internal/scheduling/nova/external_scheduler_api_test.go

@@ -33,7 +33,7 @@ func (m *mockHTTPAPIDelegate) ProcessNewDecisionFromAPI(ctx context.Context, dec
 func TestNewAPI(t *testing.T) {
 	delegate := &mockHTTPAPIDelegate{}
 
-	api := NewAPI(delegate)
+	api := NewAPI(HTTPAPIConfig{}, delegate)
 
 	if api == nil {
 		t.Fatal("NewAPI returned nil")
@@ -55,7 +55,7 @@ func TestNewAPI(t *testing.T) {
 
 func TestHTTPAPI_Init(t *testing.T) {
 	delegate := &mockHTTPAPIDelegate{}
-	api := NewAPI(delegate)
+	api := NewAPI(HTTPAPIConfig{}, delegate)
 
 	mux := http.NewServeMux()
 	api.Init(mux)
@@ -73,7 +73,7 @@ func TestHTTPAPI_Init(t *testing.T) {
 
 func TestHTTPAPI_canRunScheduler(t *testing.T) {
 	delegate := &mockHTTPAPIDelegate{}
-	api := NewAPI(delegate).(*httpAPI)
+	api := NewAPI(HTTPAPIConfig{}, delegate).(*httpAPI)
 
 	tests := []struct {
 		name        string
@@ -276,7 +276,7 @@ func TestHTTPAPI_NovaExternalScheduler(t *testing.T) {
 				},
 			}
 
-			api := NewAPI(delegate).(*httpAPI)
+			api := NewAPI(HTTPAPIConfig{}, delegate).(*httpAPI)
 
 			var body *strings.Reader
 			if tt.body != "" {
@@ -327,7 +327,7 @@ func TestHTTPAPI_NovaExternalScheduler_DecisionCreation(t *testing.T) {
 		},
 	}
 
-	api := NewAPI(delegate).(*httpAPI)
+	api := NewAPI(HTTPAPIConfig{}, delegate).(*httpAPI)
 
 	requestData := novaapi.ExternalSchedulerRequest{
 		Spec: novaapi.NovaObject[novaapi.NovaSpec]{
@@ -508,7 +508,7 @@ func TestLimitHostsToRequest(t *testing.T) {
 
 func TestHTTPAPI_inferPipelineName(t *testing.T) {
 	delegate := &mockHTTPAPIDelegate{}
-	api := NewAPI(delegate).(*httpAPI)
+	api := NewAPI(HTTPAPIConfig{}, delegate).(*httpAPI)
 
 	tests := []struct {
 		name           string