Add a feature gate for alpha dynamic volume provisioning

Enabled by default to avoid breaking people, since this was
turned on in 1.3.

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

@@ -34,6 +34,7 @@ import (
 	"k8s.io/kubernetes/pkg/cloudprovider/providers/gce"
 	"k8s.io/kubernetes/pkg/cloudprovider/providers/openstack"
 	"k8s.io/kubernetes/pkg/cloudprovider/providers/vsphere"
+	utilconfig "k8s.io/kubernetes/pkg/util/config"
 	"k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/volume"
 	"k8s.io/kubernetes/pkg/volume/aws_ebs"
@@ -125,6 +126,8 @@ func ProbeControllerVolumePlugins(cloud cloudprovider.Interface, config componen
 // TODO: remove in Kubernetes 1.5
 func NewAlphaVolumeProvisioner(cloud cloudprovider.Interface, config componentconfig.VolumeConfiguration) (volume.ProvisionableVolumePlugin, error) {
 	switch {
+	case !utilconfig.DefaultFeatureGate.DynamicVolumeProvisioning():
+		return nil, nil
 	case cloud == nil && config.EnableHostPathProvisioning:
 		return getProvisionablePluginFromVolumePlugins(host_path.ProbeVolumePlugins(
 			volume.VolumeConfig{

pkg/util/config/feature_gate.go

@@ -38,18 +38,20 @@ const (
 	// specification of gates. Examples:
 	//   AllAlpha=false,NewFeature=true  will result in newFeature=true
 	//   AllAlpha=true,NewFeature=false  will result in newFeature=false
-	allAlphaGate             = "AllAlpha"
-	externalTrafficLocalOnly = "AllowExtTrafficLocalEndpoints"
-	dynamicKubeletConfig     = "DynamicKubeletConfig"
+	allAlphaGate              = "AllAlpha"
+	externalTrafficLocalOnly  = "AllowExtTrafficLocalEndpoints"
+	dynamicKubeletConfig      = "DynamicKubeletConfig"
+	dynamicVolumeProvisioning = "DynamicVolumeProvisioning"
 )
 
 var (
 	// Default values for recorded features.  Every new feature gate should be
 	// represented here.
 	knownFeatures = map[string]featureSpec{
-		allAlphaGate:             {false, alpha},
-		externalTrafficLocalOnly: {false, alpha},
-		dynamicKubeletConfig:     {false, alpha},
+		allAlphaGate:              {false, alpha},
+		externalTrafficLocalOnly:  {false, alpha},
+		dynamicKubeletConfig:      {false, alpha},
+		dynamicVolumeProvisioning: {true, alpha},
 	}
 
 	// Special handling for a few gates.
@@ -93,6 +95,10 @@ type FeatureGate interface {
 	// alpha: v1.4
 	ExternalTrafficLocalOnly() bool
 
+	// owner: @saad-ali
+	// alpha: v1.3
+	DynamicVolumeProvisioning() bool
+
 	// TODO: Define accessors for each non-API alpha feature.
 	DynamicKubeletConfig() bool
 }
@@ -173,6 +179,11 @@ func (f *featureGate) DynamicKubeletConfig() bool {
 	return f.lookup(dynamicKubeletConfig)
 }
 
+// DynamicVolumeProvisioning returns value for dynamicVolumeProvisioning
+func (f *featureGate) DynamicVolumeProvisioning() bool {
+	return f.lookup(dynamicVolumeProvisioning)
+}
+
 func (f *featureGate) lookup(key string) bool {
 	defaultValue := f.known[key].enabled
 	if f.enabled != nil {