Add feature gates support for Kubeadm

cmd/minikube/cmd/start.go

@@ -65,6 +65,7 @@ const (
 	keepContext           = "keep-context"
 	createMount           = "mount"
 	featureGates          = "feature-gates"
+	kubeadmFeatureGates   = "kubeadm-feature-gates"
 	apiServerName         = "apiserver-name"
 	dnsDomain             = "dns-domain"
 	mountString           = "mount-string"
@@ -223,6 +224,7 @@ func runStart(cmd *cobra.Command, args []string) {
 		APIServerIPs:           apiServerIPs,
 		DNSDomain:              viper.GetString(dnsDomain),
 		FeatureGates:           viper.GetString(featureGates),
+		KubeadmFeatureGates:    viper.GetString(kubeadmFeatureGates),
 		ContainerRuntime:       viper.GetString(containerRuntime),
 		NetworkPlugin:          viper.GetString(networkPlugin),
 		ServiceCIDR:            pkgutil.DefaultServiceCIDR,
@@ -417,6 +419,7 @@ func init() {
 	startCmd.Flags().String(containerRuntime, "", "The container runtime to be used")
 	startCmd.Flags().String(networkPlugin, "", "The name of the network plugin")
 	startCmd.Flags().String(featureGates, "", "A set of key=value pairs that describe feature gates for alpha/experimental features.")
+	startCmd.Flags().String(kubeadmFeatureGates, "", "A set of key=value pairs that describe feature gates for kubeadm alpha/experimental features.")
 	startCmd.Flags().Bool(cacheImages, false, "If true, cache docker images for the current bootstrapper and load them into the machine.")
 	startCmd.Flags().Var(&extraOptions, "extra-config",
 		`A set of key=value pairs that describe configuration that may be passed to different components.

pkg/minikube/bootstrapper/kubeadm/kubeadm.go

@@ -340,6 +340,12 @@ func generateConfig(k8s config.KubernetesConfig) (string, error) {
 		return "", errors.Wrap(err, "generating extra component config for kubeadm")
 	}
 
+	// generates a map of the feature gates for kubeadm
+	kubeadmFeatureArgs, err := ParseKubeadmFeatureArgs(k8s.KubeadmFeatureGates)
+	if err != nil {
+		return "", errors.Wrap(err, "generating feature gate config for kubeadm")
+	}
+
 	opts := struct {
 		CertDir           string
 		ServiceCIDR       string
@@ -349,6 +355,7 @@ func generateConfig(k8s config.KubernetesConfig) (string, error) {
 		EtcdDataDir       string
 		NodeName          string
 		ExtraArgs         []ComponentExtraArgs
+		FeatureArgs       FeatureArgs
 	}{
 		CertDir:           util.DefaultCertPath,
 		ServiceCIDR:       util.DefaultServiceCIDR,
@@ -358,6 +365,7 @@ func generateConfig(k8s config.KubernetesConfig) (string, error) {
 		EtcdDataDir:       "/data/minikube", //TODO(r2d4): change to something else persisted
 		NodeName:          k8s.NodeName,
 		ExtraArgs:         extraComponentConfig,
+		FeatureArgs:       kubeadmFeatureArgs,
 	}
 
 	b := bytes.Buffer{}

pkg/minikube/bootstrapper/kubeadm/templates.go

@@ -38,7 +38,9 @@ etcd:
   dataDir: {{.EtcdDataDir}}
 nodeName: {{.NodeName}}
 {{range .ExtraArgs}}{{.Component}}:{{range $i, $val := printMapInOrder .Options ": " }}
-  {{$val}}{{end}}
+  {{$val}}{{end}}{{end}}
+{{if .FeatureArgs}}featureGates: {{range $i, $val := .FeatureArgs}}
+  {{$i}}: {{$val}}{{end}}
 {{end}}`))
 
 var kubeletSystemdTemplate = template.Must(template.New("kubeletSystemdTemplate").Parse(`

pkg/minikube/bootstrapper/kubeadm/versions.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"path"
 	"sort"
+	"strconv"
 	"strings"
 
 	"github.com/blang/semver"
@@ -63,6 +64,8 @@ type ComponentExtraArgs struct {
 	Options   map[string]string
 }
 
+type FeatureArgs map[string]bool
+
 var componentToKubeadmConfigKey = map[string]string{
 	Apiserver:         "apiServerExtraArgs",
 	ControllerManager: "controllerManagerExtraArgs",
@@ -108,6 +111,30 @@ func NewComponentExtraArgs(opts util.ExtraOptionSlice, version semver.Version, f
 	return kubeadmExtraArgs, nil
 }
 
+func ParseKubeadmFeatureArgs(featureGates string) (FeatureArgs, error) {
+	featureArgs := map[string]bool{}
+	for _, s := range strings.Split(featureGates, ",") {
+		if len(s) == 0 {
+			continue
+		}
+
+		fg := strings.SplitN(s, "=", 2)
+		if len(fg) != 2 {
+			return nil, fmt.Errorf("missing value for key \"%v\"", s)
+		}
+
+		k := strings.TrimSpace(fg[0])
+		v := strings.TrimSpace(fg[1])
+
+		boolValue, err := strconv.ParseBool(v)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to convert bool value \"%v\"", v)
+		}
+		featureArgs[k] = boolValue
+	}
+	return featureArgs, nil
+}
+
 func ParseKubernetesVersion(version string) (semver.Version, error) {
 	// Strip leading 'v' prefix from version for semver parsing
 	v, err := semver.Make(version[1:])

pkg/minikube/config/types.go

@@ -55,18 +55,19 @@ type MachineConfig struct {
 
 // KubernetesConfig contains the parameters used to configure the VM Kubernetes.
 type KubernetesConfig struct {
-	KubernetesVersion string
-	NodeIP            string
-	NodeName          string
-	APIServerName     string
-	APIServerNames    []string
-	APIServerIPs      []net.IP
-	DNSDomain         string
-	ContainerRuntime  string
-	NetworkPlugin     string
-	FeatureGates      string
-	ServiceCIDR       string
-	ExtraOptions      util.ExtraOptionSlice
+	KubernetesVersion   string
+	NodeIP              string
+	NodeName            string
+	APIServerName       string
+	APIServerNames      []string
+	APIServerIPs        []net.IP
+	DNSDomain           string
+	ContainerRuntime    string
+	NetworkPlugin       string
+	FeatureGates        string
+	KubeadmFeatureGates string
+	ServiceCIDR         string
+	ExtraOptions        util.ExtraOptionSlice
 
 	ShouldLoadCachedImages bool
 }