kubeadm: Make kubeadm use the right CSR approver for the right version

cmd/kubeadm/app/cmd/BUILD

@@ -45,8 +45,8 @@ go_library(
         "//pkg/printers:go_default_library",
         "//pkg/util/i18n:go_default_library",
         "//pkg/util/initsystem:go_default_library",
+        "//pkg/util/version:go_default_library",
         "//pkg/version:go_default_library",
-        "//vendor/github.com/blang/semver:go_default_library",
         "//vendor/github.com/ghodss/yaml:go_default_library",
         "//vendor/github.com/renstrom/dedent:go_default_library",
         "//vendor/github.com/spf13/cobra:go_default_library",

cmd/kubeadm/app/cmd/defaults.go

@@ -25,12 +25,9 @@ import (
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	tokenutil "k8s.io/kubernetes/cmd/kubeadm/app/util/token"
-
-	"github.com/blang/semver"
+	"k8s.io/kubernetes/pkg/util/version"
 )
 
-var minK8sVersion = semver.MustParse(kubeadmconstants.MinimumControlPlaneVersion)
-
 func setInitDynamicDefaults(cfg *kubeadmapi.MasterConfiguration) error {
 
 	// Choose the right address for the API Server to advertise. If the advertise address is localhost or 0.0.0.0, the default interface's IP address is used
@@ -48,13 +45,13 @@ func setInitDynamicDefaults(cfg *kubeadmapi.MasterConfiguration) error {
 	}
 	cfg.KubernetesVersion = ver
 
-	// Omit the "v" in the beginning, otherwise semver will fail
-	k8sVersion, err := semver.Parse(cfg.KubernetesVersion[1:])
+	// Parse the given kubernetes version and make sure it's higher than the lowest supported
+	k8sVersion, err := version.ParseSemantic(cfg.KubernetesVersion)
 	if err != nil {
 		return fmt.Errorf("couldn't parse kubernetes version %q: %v", cfg.KubernetesVersion, err)
 	}
-	if k8sVersion.LT(minK8sVersion) {
-		return fmt.Errorf("this version of kubeadm only supports deploying clusters with the control plane version >= v%s. Current version: %s", kubeadmconstants.MinimumControlPlaneVersion, cfg.KubernetesVersion)
+	if k8sVersion.LessThan(kubeadmconstants.MinimumControlPlaneVersion) {
+		return fmt.Errorf("this version of kubeadm only supports deploying clusters with the control plane version >= %s. Current version: %s", kubeadmconstants.MinimumControlPlaneVersion.String(), cfg.KubernetesVersion)
 	}
 
 	fmt.Printf("[init] Using Kubernetes version: %s\n", cfg.KubernetesVersion)

cmd/kubeadm/app/constants/BUILD

@@ -11,7 +11,10 @@ go_library(
     name = "go_default_library",
     srcs = ["constants.go"],
     tags = ["automanaged"],
-    deps = ["//vendor/k8s.io/client-go/pkg/api/v1:go_default_library"],
+    deps = [
+        "//pkg/util/version:go_default_library",
+        "//vendor/k8s.io/client-go/pkg/api/v1:go_default_library",
+    ],
 )
 
 filegroup(

cmd/kubeadm/app/constants/constants.go

@@ -21,6 +21,7 @@ import (
 	"time"
 
 	"k8s.io/client-go/pkg/api/v1"
+	"k8s.io/kubernetes/pkg/util/version"
 )
 
 const (
@@ -58,9 +59,6 @@ const (
 	ControllerManagerKubeConfigFileName = "controller-manager.conf"
 	SchedulerKubeConfigFileName         = "scheduler.conf"
 
-	// Important: a "v"-prefix shouldn't exist here; semver doesn't allow that
-	MinimumControlPlaneVersion = "1.6.0-beta.3"
-
 	// Some well-known users and groups in the core Kubernetes authorization system
 
 	ControllerManagerUser = "system:kube-controller-manager"
@@ -109,4 +107,13 @@ var (
 
 	// DefaultTokenUsages specifies the default functions a token will get
 	DefaultTokenUsages = []string{"signing", "authentication"}
+
+	// MinimumControlPlaneVersion specifies the minimum control plane version kubeadm can deploy
+	MinimumControlPlaneVersion = version.MustParseSemantic("v1.6.0")
+
+	// MinimumCSRSARApproverVersion specifies the minimum kubernetes version that can be used for enabling the new-in-v1.7 CSR approver based on a SubjectAccessReview
+	MinimumCSRSARApproverVersion = version.MustParseSemantic("v1.7.0-beta.0")
+
+	// MinimumAPIAggregationVersion specifies the minimum kubernetes version that can be used enabling the API aggregation in the apiserver and the front proxy flags
+	MinimumAPIAggregationVersion = version.MustParseSemantic("v1.7.0-alpha.1")
 )

cmd/kubeadm/app/master/BUILD

@@ -22,6 +22,7 @@ go_library(
         "//cmd/kubeadm/app/constants:go_default_library",
         "//cmd/kubeadm/app/images:go_default_library",
         "//cmd/kubeadm/app/util/kubeconfig:go_default_library",
+        "//pkg/bootstrap/api:go_default_library",
         "//pkg/kubeapiserver/authorizer/modes:go_default_library",
         "//pkg/kubectl/cmd/util:go_default_library",
         "//pkg/util/version:go_default_library",

cmd/kubeadm/app/master/manifests.go

@@ -33,6 +33,7 @@ import (
 	kubeadmapiext "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha1"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/images"
+	bootstrapapi "k8s.io/kubernetes/pkg/bootstrap/api"
 	authzmodes "k8s.io/kubernetes/pkg/kubeapiserver/authorizer/modes"
 	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 	"k8s.io/kubernetes/pkg/util/version"
@@ -53,10 +54,6 @@ const (
 	kubeProxy             = "kube-proxy"
 )
 
-var (
-	v170 = version.MustParseSemantic("v1.7.0-alpha.0")
-)
-
 // WriteStaticPodManifests builds manifest objects based on user provided configuration and then dumps it to disk
 // where kubelet will pick and schedule them.
 func WriteStaticPodManifests(cfg *kubeadmapi.MasterConfiguration) error {
@@ -97,7 +94,7 @@ func WriteStaticPodManifests(cfg *kubeadmapi.MasterConfiguration) error {
 		kubeControllerManager: componentPod(api.Container{
 			Name:          kubeControllerManager,
 			Image:         images.GetCoreImage(images.KubeControllerManagerImage, cfg, kubeadmapi.GlobalEnvParams.HyperkubeImage),
-			Command:       getControllerManagerCommand(cfg, false),
+			Command:       getControllerManagerCommand(cfg, false, k8sVersion),
 			VolumeMounts:  volumeMounts,
 			LivenessProbe: componentProbe(10252, "/healthz", api.URISchemeHTTP),
 			Resources:     componentResources("200m"),
@@ -349,7 +346,7 @@ func getAPIServerCommand(cfg *kubeadmapi.MasterConfiguration, selfHosted bool, k
 		"requestheader-client-ca-file":       filepath.Join(cfg.CertificatesDir, kubeadmconstants.FrontProxyCACertName),
 		"requestheader-allowed-names":        "front-proxy-client",
 	}
-	if k8sVersion.AtLeast(v170) {
+	if k8sVersion.AtLeast(kubeadmconstants.MinimumAPIAggregationVersion) {
 		// add options which allow the kube-apiserver to act as a front-proxy to aggregated API servers
 		defaultArguments["proxy-client-cert-file"] = filepath.Join(cfg.CertificatesDir, kubeadmconstants.FrontProxyClientCertName)
 		defaultArguments["proxy-client-key-file"] = filepath.Join(cfg.CertificatesDir, kubeadmconstants.FrontProxyClientKeyName)
@@ -409,7 +406,7 @@ func getEtcdCommand(cfg *kubeadmapi.MasterConfiguration) []string {
 	return command
 }
 
-func getControllerManagerCommand(cfg *kubeadmapi.MasterConfiguration, selfHosted bool) []string {
+func getControllerManagerCommand(cfg *kubeadmapi.MasterConfiguration, selfHosted bool, k8sVersion *version.Version) []string {
 	var command []string
 
 	// self-hosted controller-manager needs to wait on a lock
@@ -428,6 +425,11 @@ func getControllerManagerCommand(cfg *kubeadmapi.MasterConfiguration, selfHosted
 		"use-service-account-credentials":  "true",
 		"controllers":                      "*,bootstrapsigner,tokencleaner",
 	}
+	if k8sVersion.LessThan(kubeadmconstants.MinimumCSRSARApproverVersion) {
+		// enable the former CSR group approver for v1.6 clusters.
+		// TODO(luxas): Remove this once we're targeting v1.8 at HEAD
+		defaultArguments["insecure-experimental-approve-all-kubelet-csrs-for-group"] = bootstrapapi.BootstrapGroup
+	}
 
 	command = getComponentBaseCommand(controllerManager)
 	command = append(command, getExtraParameters(cfg.ControllerManagerExtraArgs, defaultArguments)...)

cmd/kubeadm/app/master/manifests_test.go

@@ -667,7 +667,8 @@ func TestGetControllerManagerCommand(t *testing.T) {
 	}{
 		{
 			cfg: &kubeadmapi.MasterConfiguration{
-				CertificatesDir: testCertsDir,
+				CertificatesDir:   testCertsDir,
+				KubernetesVersion: "v1.7.0",
 			},
 			expected: []string{
 				"kube-controller-manager",
@@ -684,8 +685,28 @@ func TestGetControllerManagerCommand(t *testing.T) {
 		},
 		{
 			cfg: &kubeadmapi.MasterConfiguration{
-				CloudProvider:   "foo",
-				CertificatesDir: testCertsDir,
+				CertificatesDir:   testCertsDir,
+				KubernetesVersion: "v1.6.4",
+			},
+			expected: []string{
+				"kube-controller-manager",
+				"--address=127.0.0.1",
+				"--leader-elect=true",
+				"--kubeconfig=" + kubeadmapi.GlobalEnvParams.KubernetesDir + "/controller-manager.conf",
+				"--root-ca-file=" + testCertsDir + "/ca.crt",
+				"--service-account-private-key-file=" + testCertsDir + "/sa.key",
+				"--cluster-signing-cert-file=" + testCertsDir + "/ca.crt",
+				"--cluster-signing-key-file=" + testCertsDir + "/ca.key",
+				"--use-service-account-credentials=true",
+				"--controllers=*,bootstrapsigner,tokencleaner",
+				"--insecure-experimental-approve-all-kubelet-csrs-for-group=system:bootstrappers",
+			},
+		},
+		{
+			cfg: &kubeadmapi.MasterConfiguration{
+				CloudProvider:     "foo",
+				CertificatesDir:   testCertsDir,
+				KubernetesVersion: "v1.7.0",
 			},
 			expected: []string{
 				"kube-controller-manager",
@@ -703,8 +724,9 @@ func TestGetControllerManagerCommand(t *testing.T) {
 		},
 		{
 			cfg: &kubeadmapi.MasterConfiguration{
-				Networking:      kubeadm.Networking{PodSubnet: "bar"},
-				CertificatesDir: testCertsDir,
+				Networking:        kubeadm.Networking{PodSubnet: "bar"},
+				CertificatesDir:   testCertsDir,
+				KubernetesVersion: "v1.7.0",
 			},
 			expected: []string{
 				"kube-controller-manager",
@@ -724,7 +746,7 @@ func TestGetControllerManagerCommand(t *testing.T) {
 	}
 
 	for _, rt := range tests {
-		actual := getControllerManagerCommand(rt.cfg, false)
+		actual := getControllerManagerCommand(rt.cfg, false, version.MustParseSemantic(rt.cfg.KubernetesVersion))
 		sort.Strings(actual)
 		sort.Strings(rt.expected)
 		if !reflect.DeepEqual(actual, rt.expected) {
@@ -935,7 +957,7 @@ func TestVersionCompare(t *testing.T) {
 		"v1.7.1",
 	}
 	for _, v := range versions {
-		if !version.MustParseSemantic(v).AtLeast(v170) {
+		if !version.MustParseSemantic(v).AtLeast(kubeadmconstants.MinimumAPIAggregationVersion) {
 			t.Errorf("err")
 		}
 	}

cmd/kubeadm/app/master/selfhosted.go

@@ -124,7 +124,12 @@ func launchSelfHostedAPIServer(cfg *kubeadmapi.MasterConfiguration, client *clie
 func launchSelfHostedControllerManager(cfg *kubeadmapi.MasterConfiguration, client *clientset.Clientset, volumes []v1.Volume, volumeMounts []v1.VolumeMount) error {
 	start := time.Now()
 
-	ctrlMgr := getControllerManagerDeployment(cfg, volumes, volumeMounts)
+	kubeVersion, err := version.ParseSemantic(cfg.KubernetesVersion)
+	if err != nil {
+		return err
+	}
+
+	ctrlMgr := getControllerManagerDeployment(cfg, volumes, volumeMounts, kubeVersion)
 	if _, err := client.Extensions().Deployments(metav1.NamespaceSystem).Create(&ctrlMgr); err != nil {
 		return fmt.Errorf("failed to create self-hosted %q deployment [%v]", kubeControllerManager, err)
 	}
@@ -232,7 +237,7 @@ func getAPIServerDS(cfg *kubeadmapi.MasterConfiguration, volumes []v1.Volume, vo
 	return ds
 }
 
-func getControllerManagerDeployment(cfg *kubeadmapi.MasterConfiguration, volumes []v1.Volume, volumeMounts []v1.VolumeMount) ext.Deployment {
+func getControllerManagerDeployment(cfg *kubeadmapi.MasterConfiguration, volumes []v1.Volume, volumeMounts []v1.VolumeMount, kubeVersion *version.Version) ext.Deployment {
 	d := ext.Deployment{
 		TypeMeta: metav1.TypeMeta{
 			APIVersion: "extensions/v1beta1",
@@ -268,7 +273,7 @@ func getControllerManagerDeployment(cfg *kubeadmapi.MasterConfiguration, volumes
 						{
 							Name:          "self-hosted-" + kubeControllerManager,
 							Image:         images.GetCoreImage(images.KubeControllerManagerImage, cfg, kubeadmapi.GlobalEnvParams.HyperkubeImage),
-							Command:       getControllerManagerCommand(cfg, true),
+							Command:       getControllerManagerCommand(cfg, true, kubeVersion),
 							VolumeMounts:  volumeMounts,
 							LivenessProbe: componentProbe(10252, "/healthz", v1.URISchemeHTTP),
 							Resources:     componentResources("200m"),