Merge pull request #75762 from SataQiu/fix-kubeadm-gates-20190327

cmd/kubeadm/app/cmd/config.go

@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"strings"
 
 	"github.com/lithammer/dedent"
 	"github.com/pkg/errors"
@@ -519,7 +518,6 @@ func AddImagesCommonConfigFlags(flagSet *flag.FlagSet, cfg *kubeadmapiv1beta1.In
 		&cfg.ClusterConfiguration.KubernetesVersion, "kubernetes-version", cfg.ClusterConfiguration.KubernetesVersion,
 		`Choose a specific Kubernetes version for the control plane.`,
 	)
-	flagSet.StringVar(featureGatesString, "feature-gates", *featureGatesString, "A set of key=value pairs that describe feature gates for various features. "+
-		"Options are:\n"+strings.Join(features.KnownFeatures(&features.InitFeatureGates), "\n"))
+	options.AddFeatureGatesStringFlag(flagSet, featureGatesString)
 	flagSet.StringVar(cfgPath, "config", *cfgPath, "Path to kubeadm config file.")
 }

cmd/kubeadm/app/cmd/init.go

@@ -21,7 +21,6 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"strings"
 	"text/template"
 
 	"github.com/lithammer/dedent"
@@ -235,8 +234,7 @@ func AddInitConfigFlags(flagSet *flag.FlagSet, cfg *kubeadmapiv1beta1.InitConfig
 		`Specify the node name.`,
 	)
 	cmdutil.AddCRISocketFlag(flagSet, &cfg.NodeRegistration.CRISocket)
-	flagSet.StringVar(featureGatesString, options.FeatureGatesString, *featureGatesString, "A set of key=value pairs that describe feature gates for various features. "+
-		"Options are:\n"+strings.Join(features.KnownFeatures(&features.InitFeatureGates), "\n"))
+	options.AddFeatureGatesStringFlag(flagSet, featureGatesString)
 }
 
 // AddInitOtherFlags adds init flags that are not bound to a configuration file to the given flagset

cmd/kubeadm/app/cmd/options/BUILD

@@ -14,6 +14,7 @@ go_library(
     deps = [
         "//cmd/kubeadm/app/apis/kubeadm/v1beta1:go_default_library",
         "//cmd/kubeadm/app/constants:go_default_library",
+        "//cmd/kubeadm/app/features:go_default_library",
         "//staging/src/k8s.io/cluster-bootstrap/token/api:go_default_library",
         "//staging/src/k8s.io/component-base/cli/flag:go_default_library",
         "//vendor/github.com/spf13/pflag:go_default_library",

cmd/kubeadm/app/cmd/options/generic.go

@@ -17,9 +17,12 @@ limitations under the License.
 package options
 
 import (
+	"strings"
+
 	"github.com/spf13/pflag"
 	cliflag "k8s.io/component-base/cli/flag"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
+	"k8s.io/kubernetes/cmd/kubeadm/app/features"
 )
 
 // AddKubeConfigFlag adds the --kubeconfig flag to the given flagset
@@ -58,3 +61,14 @@ func AddControlPlanExtraArgsFlags(fs *pflag.FlagSet, apiServerExtraArgs, control
 func AddImageMetaFlags(fs *pflag.FlagSet, imageRepository *string) {
 	fs.StringVar(imageRepository, ImageRepository, *imageRepository, "Choose a container registry to pull control plane images from")
 }
+
+// AddFeatureGatesStringFlag adds the --feature-gates flag to the given flagset
+func AddFeatureGatesStringFlag(fs *pflag.FlagSet, featureGatesString *string) {
+	if knownFeatures := features.KnownFeatures(&features.InitFeatureGates); len(knownFeatures) > 0 {
+		fs.StringVar(featureGatesString, FeatureGatesString, *featureGatesString, "A set of key=value pairs that describe feature gates for various features. "+
+			"Options are:\n"+strings.Join(knownFeatures, "\n"))
+	} else {
+		fs.StringVar(featureGatesString, FeatureGatesString, *featureGatesString, "A set of key=value pairs that describe feature gates for various features. "+
+			"No feature gates are available in this release.")
+	}
+}

cmd/kubeadm/app/cmd/upgrade/upgrade.go

@@ -18,7 +18,6 @@ package upgrade
 
 import (
 	"io"
-	"strings"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
@@ -26,7 +25,6 @@ import (
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
 	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
-	"k8s.io/kubernetes/cmd/kubeadm/app/features"
 )
 
 // applyPlanFlags holds the values for the common flags in `kubeadm upgrade apply` and `kubeadm upgrade plan`
@@ -73,7 +71,6 @@ func addApplyPlanFlags(fs *pflag.FlagSet, flags *applyPlanFlags) {
 	fs.BoolVar(&flags.allowExperimentalUpgrades, "allow-experimental-upgrades", flags.allowExperimentalUpgrades, "Show unstable versions of Kubernetes as an upgrade alternative and allow upgrading to an alpha/beta/release candidate versions of Kubernetes.")
 	fs.BoolVar(&flags.allowRCUpgrades, "allow-release-candidate-upgrades", flags.allowRCUpgrades, "Show release candidate versions of Kubernetes as an upgrade alternative and allow upgrading to a release candidate versions of Kubernetes.")
 	fs.BoolVar(&flags.printConfig, "print-config", flags.printConfig, "Specifies whether the configuration file that will be used in the upgrade should be printed or not.")
-	fs.StringVar(&flags.featureGatesString, "feature-gates", flags.featureGatesString, "A set of key=value pairs that describe feature gates for various features. "+
-		"Options are:\n"+strings.Join(features.KnownFeatures(&features.InitFeatureGates), "\n"))
+	options.AddFeatureGatesStringFlag(fs, &flags.featureGatesString)
 	options.AddIgnorePreflightErrorsFlag(fs, &flags.ignorePreflightErrors)
 }