DRA scheduler: fail in PreFilter when DRAPrioritizedList is disabled and used

This was previously caught during Filter by the allocator check. Doing it
sooner avoids wasting resources on a pod which ultimately cannot get scheduled.

While at it, be a bit more clear about which feature is disabled. The user
might not know that.

Author: pohly

pkg/scheduler/framework/plugins/dynamicresources/dynamicresources.go

@@ -415,6 +415,9 @@ func (pl *DynamicResources) PreFilter(ctx context.Context, state *framework.Cycl
 						return nil, status
 					}
 				} else {
+					if !pl.enablePrioritizedList {
+						return nil, statusUnschedulable(logger, fmt.Sprintf("resource claim %s, request %s: has subrequests, but the DRAPrioritizedList feature is disabled", klog.KObj(claim), request.Name))
+					}
 					for _, subRequest := range request.FirstAvailable {
 						qualRequestName := strings.Join([]string{request.Name, subRequest.Name}, "/")
 						if status := pl.validateDeviceClass(logger, subRequest.DeviceClassName, qualRequestName); status != nil {

pkg/scheduler/framework/plugins/dynamicresources/dynamicresources_test.go

@@ -861,10 +861,11 @@ func TestPlugin(t *testing.T) {
 			claims:                   []*resourceapi.ResourceClaim{claimWithPrioritzedList},
 			classes:                  []*resourceapi.DeviceClass{deviceClass},
 			want: want{
-				filter: perNodeResult{
-					workerNode.Name: {
-						status: framework.NewStatus(framework.UnschedulableAndUnresolvable, `claim default/my-pod-my-resource, request req-1: has subrequests, but the feature is disabled`),
-					},
+				prefilter: result{
+					status: framework.NewStatus(framework.UnschedulableAndUnresolvable, `claim default/my-pod-my-resource, request req-1: has subrequests, but the DRAPrioritizedList feature is disabled`),
+				},
+				postfilter: result{
+					status: framework.NewStatus(framework.Unschedulable, `no new claims to deallocate`),
 				},
 			},
 		},

staging/src/k8s.io/dynamic-resource-allocation/structured/allocator.go

@@ -171,7 +171,7 @@ func (a *Allocator) Allocate(ctx context.Context, node *v1.Node) (finalResult []
 			// Error out if the prioritizedList feature is not enabled and the request
 			// has subrequests. This is to avoid surprising behavior for users.
 			if !a.prioritizedListEnabled && hasSubRequests {
-				return nil, fmt.Errorf("claim %s, request %s: has subrequests, but the feature is disabled", klog.KObj(claim), request.Name)
+				return nil, fmt.Errorf("claim %s, request %s: has subrequests, but the DRAPrioritizedList feature is disabled", klog.KObj(claim), request.Name)
 			}
 
 			if hasSubRequests {