Merge pull request kubernetes#90439 from SataQiu/dual-stack-node-cidr-20200424

Dual-stack: make nodeipam compatible with existing single-stack clusters when dual-stack feature gate become enabled by default

Author: k8s-ci-robot

cmd/kube-controller-manager/app/core.go

@@ -157,13 +157,13 @@ func startNodeIpamController(ctx ControllerContext) (http.Handler, bool, error)
 	}
 
 	var nodeCIDRMaskSizeIPv4, nodeCIDRMaskSizeIPv6 int
-	if utilfeature.DefaultFeatureGate.Enabled(features.IPv6DualStack) {
+	if dualStack {
 		// only --node-cidr-mask-size-ipv4 and --node-cidr-mask-size-ipv6 supported with dual stack clusters.
 		// --node-cidr-mask-size flag is incompatible with dual stack clusters.
 		nodeCIDRMaskSizeIPv4, nodeCIDRMaskSizeIPv6, err = setNodeCIDRMaskSizesDualStack(ctx.ComponentConfig.NodeIPAMController)
 	} else {
 		// only --node-cidr-mask-size supported with single stack clusters.
-		// --node-cidr-mask-size-ipv4 and --node-cidr-mask-size-ipv6 flags are incompatible with dual stack clusters.
+		// --node-cidr-mask-size-ipv4 and --node-cidr-mask-size-ipv6 flags are incompatible with single stack clusters.
 		nodeCIDRMaskSizeIPv4, nodeCIDRMaskSizeIPv6, err = setNodeCIDRMaskSizes(ctx.ComponentConfig.NodeIPAMController)
 	}