Enhance controller setup based on available CRDs

This enhances the setup of the InferenceService controller and the InferenceGraph controller. Instead of relying on the `defaultDeploymentMode` configuration to determine what CRDs to watch, the setup now checks whether KNative Services and Istio VirtualServices are available in the cluster and setup the watches (invoke `Owns`) accordingly.

This enhancement has the following advantages:
* A crashloop is prevented if the CRDs are missing in the cluster. The user would still be able to create InferenceServices by taking care of annotating the ISVC for RawDeployment mode.
* If RawDeployment mode is configured as the default mode, the controllers would still watch for KNative and Istio resources if these components are available. This will let the controller watch for changes for the dependent resources if the user uses Serverless mode for some of the InferenceServices.
* In the InferenceService controller, the watch for the VirtualServices is still conditioned to the value of the `disableVirtualHost` configuration.

Signed-off-by: Edgar Hernández <23639005+israel-hdez@users.noreply.github.com>

pkg/controller/v1alpha1/inferencegraph/controller.go

@@ -31,6 +31,7 @@ import (
 	v1beta1api "github.com/kserve/kserve/pkg/apis/serving/v1beta1"
 	"github.com/kserve/kserve/pkg/constants"
 	isvcutils "github.com/kserve/kserve/pkg/controller/v1beta1/inferenceservice/utils"
+	"github.com/kserve/kserve/pkg/utils"
 	"github.com/pkg/errors"
 	appsv1 "k8s.io/api/apps/v1"
 	v1 "k8s.io/api/core/v1"
@@ -266,15 +267,20 @@ func inferenceGraphReadiness(status v1alpha1api.InferenceGraphStatus) bool {
 }
 
 func (r *InferenceGraphReconciler) SetupWithManager(mgr ctrl.Manager, deployConfig *v1beta1api.DeployConfig) error {
-	if deployConfig.DefaultDeploymentMode == string(constants.RawDeployment) {
-		return ctrl.NewControllerManagedBy(mgr).
-			For(&v1alpha1api.InferenceGraph{}).
-			Owns(&appsv1.Deployment{}).
-			Complete(r)
+	ksvcFound, err := utils.IsCrdAvailable(mgr.GetConfig(), "serving.knative.dev/v1", "Service")
+	if err != nil {
+		return err
+	}
+
+	ctrlBuilder := ctrl.NewControllerManagedBy(mgr).
+		For(&v1alpha1api.InferenceGraph{}).
+		Owns(&appsv1.Deployment{})
+
+	if ksvcFound {
+		ctrlBuilder = ctrlBuilder.Owns(&knservingv1.Service{})
 	} else {
-		return ctrl.NewControllerManagedBy(mgr).
-			For(&v1alpha1api.InferenceGraph{}).
-			Owns(&knservingv1.Service{}).
-			Complete(r)
+		r.Log.Info("The InferenceGraph controller won't watch serving.knative.dev/v1/Service resources because the CRD is not available.")
 	}
+
+	return ctrlBuilder.Complete(r)
 }

pkg/controller/v1beta1/inferenceservice/controller.go

@@ -296,26 +296,33 @@ func inferenceServiceStatusEqual(s1, s2 v1beta1api.InferenceServiceStatus, deplo
 }
 
 func (r *InferenceServiceReconciler) SetupWithManager(mgr ctrl.Manager, deployConfig *v1beta1api.DeployConfig, ingressConfig *v1beta1api.IngressConfig) error {
-	if deployConfig.DefaultDeploymentMode == string(constants.RawDeployment) {
-		return ctrl.NewControllerManagedBy(mgr).
-			For(&v1beta1api.InferenceService{}).
-			Owns(&appsv1.Deployment{}).
-			Complete(r)
-	} else if ingressConfig.DisableIstioVirtualHost == false {
-		return ctrl.NewControllerManagedBy(mgr).
-			For(&v1beta1api.InferenceService{}).
-			Owns(&knservingv1.Service{}).
-			Owns(&istioclientv1beta1.VirtualService{}).
-			Owns(&appsv1.Deployment{}).
-			Complete(r)
+	ksvcFound, err := utils.IsCrdAvailable(mgr.GetConfig(), "serving.knative.dev/v1", "Service")
+	if err != nil {
+		return err
+	}
+
+	vsFound, err := utils.IsCrdAvailable(mgr.GetConfig(), "networking.istio.io/v1beta1", "VirtualService")
+	if err != nil {
+		return err
+	}
+
+	ctrlBuilder := ctrl.NewControllerManagedBy(mgr).
+		For(&v1beta1api.InferenceService{}).
+		Owns(&appsv1.Deployment{})
+
+	if ksvcFound {
+		ctrlBuilder = ctrlBuilder.Owns(&knservingv1.Service{})
+	} else {
+		r.Log.Info("The InferenceService controller won't watch serving.knative.dev/v1/Service resources because the CRD is not available.")
+	}
+
+	if vsFound && ingressConfig.DisableIstioVirtualHost == false {
+		ctrlBuilder = ctrlBuilder.Owns(&istioclientv1beta1.VirtualService{})
 	} else {
-		return ctrl.NewControllerManagedBy(mgr).
-			For(&v1beta1api.InferenceService{}).
-			Owns(&knservingv1.Service{}).
-			Owns(&appsv1.Deployment{}).
-			Complete(r)
+		r.Log.Info("The InferenceService controller won't watch networking.istio.io/v1beta1/VirtualService resources because the CRD is not available.")
 	}
 
+	return ctrlBuilder.Complete(r)
 }
 
 func (r *InferenceServiceReconciler) deleteExternalResources(isvc *v1beta1api.InferenceService) error {

pkg/utils/utils.go

@@ -21,6 +21,10 @@ import (
 
 	"github.com/kserve/kserve/pkg/constants"
 	v1 "k8s.io/api/core/v1"
+	apierr "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/discovery"
+	"k8s.io/client-go/rest"
 )
 
 /* NOTE TO AUTHORS:
@@ -29,6 +33,8 @@ import (
  * Please add functional style container operations sparingly and intentionally.
  */
 
+var gvResourcesCache map[string]*metav1.APIResourceList
+
 func Filter(origin map[string]string, predicate func(string) bool) map[string]string {
 	result := make(map[string]string)
 	for k, v := range origin {
@@ -169,3 +175,41 @@ func AppendPortIfNotExists(slice []v1.ContainerPort, elems ...v1.ContainerPort)
 	}
 	return slice
 }
+
+// IsCrdAvailable checks if a given CRD is present in the cluster by verifying the
+// existence of its API.
+func IsCrdAvailable(config *rest.Config, groupVersion, kind string) (bool, error) {
+	var gvResources *metav1.APIResourceList
+	var ok bool
+
+	if gvResourcesCache == nil {
+		gvResourcesCache = make(map[string]*metav1.APIResourceList)
+	}
+
+	if gvResources, ok = gvResourcesCache[groupVersion]; !ok {
+		discoveryClient, newClientErr := discovery.NewDiscoveryClientForConfig(config)
+		if newClientErr != nil {
+			return false, newClientErr
+		}
+
+		var getGvResourcesErr error
+		gvResources, getGvResourcesErr = discoveryClient.ServerResourcesForGroupVersion(groupVersion)
+		if getGvResourcesErr != nil && !apierr.IsNotFound(getGvResourcesErr) {
+			return false, getGvResourcesErr
+		}
+
+		gvResourcesCache[groupVersion] = gvResources
+	}
+
+	found := false
+	if gvResources != nil {
+		for _, crd := range gvResources.APIResources {
+			if crd.Kind == kind {
+				found = true
+				break
+			}
+		}
+	}
+
+	return found, nil
+}