Merge pull request kubernetes#80145 from Nordix/kubeadm-ds-feature-gate

Adds kubeadm feature-gate for dual-stack (IPv6DualStack)

Author: k8s-ci-robot

cmd/kubeadm/app/features/features.go

@@ -31,14 +31,17 @@ const (
 
 	// CoreDNS is GA in v1.11
 	CoreDNS = "CoreDNS"
+	// IPv6DualStack is expected to be alpha in v1.16
+	IPv6DualStack = "IPv6DualStack"
 )
 
 var coreDNSMessage = "featureGates:CoreDNS has been removed in v1.13\n" +
 	"\tUse kubeadm-config to select which DNS addon to install."
 
 // InitFeatureGates are the default feature gates for the init command
 var InitFeatureGates = FeatureList{
-	CoreDNS: {FeatureSpec: featuregate.FeatureSpec{Default: true, PreRelease: featuregate.Deprecated}, HiddenInHelpText: true, DeprecationMessage: coreDNSMessage},
+	CoreDNS:       {FeatureSpec: featuregate.FeatureSpec{Default: true, PreRelease: featuregate.Deprecated}, HiddenInHelpText: true, DeprecationMessage: coreDNSMessage},
+	IPv6DualStack: {FeatureSpec: featuregate.FeatureSpec{Default: false, PreRelease: featuregate.Alpha}},
 }
 
 // Feature represents a feature being gated