Fix DRA enablement logic

The DRA scheduler plugin is enabled by default since 1.34. We have to
hack it to be disabled if the CA DRA logic is disabled via the flag.
Without this, the DRA scheduler plugin is enabled but not set up
properly, and panics.

Author: towca

cluster-autoscaler/main.go

@@ -349,12 +349,13 @@ func main() {
 
 	autoscalingOpts := flags.AutoscalingOptions()
 
-	// If the DRA flag is passed, we need to set the DRA feature gate as well. The selection of scheduler plugins for the default
-	// scheduling profile depends on feature gates, and the DRA plugin is only included if the DRA feature gate is enabled. The DRA
-	// plugin itself also checks the DRA feature gate and doesn't do anything if it's not enabled.
-	if autoscalingOpts.DynamicResourceAllocationEnabled && !featureGate.Enabled(features.DynamicResourceAllocation) {
-		if err := featureGate.SetFromMap(map[string]bool{string(features.DynamicResourceAllocation): true}); err != nil {
-			klog.Fatalf("couldn't enable the DRA feature gate: %v", err)
+	// The DRA feature controls whether the DRA scheduler plugin is selected in scheduler framework. The local DRA flag controls whether
+	// DRA logic is enabled in Cluster Autoscaler. The 2 values should be in sync - enabling DRA logic in CA without selecting the DRA scheduler
+	// plugin doesn't actually do anything, and selecting the DRA scheduler plugin without enabling DRA logic in CA means the plugin is not set up
+	// correctly and can panic.
+	if autoscalingOpts.DynamicResourceAllocationEnabled != featureGate.Enabled(features.DynamicResourceAllocation) {
+		if err := featureGate.SetFromMap(map[string]bool{string(features.DynamicResourceAllocation): autoscalingOpts.DynamicResourceAllocationEnabled}); err != nil {
+			klog.Fatalf("couldn't set the DRA feature gate to %v: %v", autoscalingOpts.DynamicResourceAllocationEnabled, err)
 		}
 	}