Add feature gate for enabling fallback strategy

Author: lhp-nemlig

internal/manifests/targetallocator/configmap.go

@@ -90,6 +90,11 @@ func ConfigMap(params Params) (*corev1.ConfigMap, error) {
 	} else {
 		taConfig["allocation_strategy"] = v1beta1.TargetAllocatorAllocationStrategyConsistentHashing
 	}
+
+	if featuregate.EnableTargetAllocatorFallbackStrategy.IsEnabled() {
+		taConfig["allocation_fallback_strategy"] = v1beta1.TargetAllocatorAllocationStrategyConsistentHashing
+	}
+
 	taConfig["filter_strategy"] = taSpec.FilterStrategy
 
 	if taSpec.PrometheusCR.Enabled {

pkg/featuregate/featuregate.go

@@ -67,6 +67,14 @@ var (
 		featuregate.WithRegisterDescription("enables mTLS between the target allocator and the collector"),
 		featuregate.WithRegisterFromVersion("v0.111.0"),
 	)
+	// EnableTargetAllocatorFallbackStrategy is the feature gate that enables consistent-hashing as the fallback
+	// strategy for allocation strategies that might not assign all jobs (per-node).
+	EnableTargetAllocatorFallbackStrategy = featuregate.GlobalRegistry().MustRegister(
+		"operator.targetallocator.mtls",
+		featuregate.StageAlpha,
+		featuregate.WithRegisterDescription("enables fallback allocation strategy for the target allocator"),
+		featuregate.WithRegisterFromVersion("v0.114.0"),
+	)
 	// EnableConfigDefaulting is the feature gate that enables the operator to default the endpoint for known components.
 	EnableConfigDefaulting = featuregate.GlobalRegistry().MustRegister(
 		"operator.collector.default.config",