Merge pull request #48594 from GheRivero/kubeadm_nodename

Automatic merge from submit-queue

Add node-name flag to `init` phase

**What this PR does / why we need it**: Allow to specify a node-name instead of relaying in `os.Hostname()`
This is useful where kubelet use the name given by the cloud-provider to
register the node.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: Partially fix: kubernetes/kubeadm#64

**Release note**:
```release-note
Added new flag to `kubeadm init`: --node-name, that lets you specify the name of the Node object that will be created
```

cmd/kubeadm/app/apis/kubeadm/types.go

@@ -37,6 +37,7 @@ type MasterConfiguration struct {
 	Networking         Networking
 	KubernetesVersion  string
 	CloudProvider      string
+	NodeName           string
 	AuthorizationModes []string
 
 	Token    string

cmd/kubeadm/app/apis/kubeadm/v1alpha1/types.go

@@ -30,6 +30,7 @@ type MasterConfiguration struct {
 	Networking         Networking `json:"networking"`
 	KubernetesVersion  string     `json:"kubernetesVersion"`
 	CloudProvider      string     `json:"cloudProvider"`
+	NodeName           string     `json:"nodeName"`
 	AuthorizationModes []string   `json:"authorizationModes"`
 
 	Token    string        `json:"token"`

cmd/kubeadm/app/apis/kubeadm/validation/BUILD

@@ -31,6 +31,7 @@ go_library(
         "//pkg/api/validation:go_default_library",
         "//pkg/kubeapiserver/authorizer/modes:go_default_library",
         "//pkg/registry/core/service/ipallocator:go_default_library",
+        "//pkg/util/node:go_default_library",
         "//vendor/github.com/spf13/pflag:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/validation:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/validation/field:go_default_library",

cmd/kubeadm/app/apis/kubeadm/validation/validation.go

@@ -34,6 +34,7 @@ import (
 	apivalidation "k8s.io/kubernetes/pkg/api/validation"
 	authzmodes "k8s.io/kubernetes/pkg/kubeapiserver/authorizer/modes"
 	"k8s.io/kubernetes/pkg/registry/core/service/ipallocator"
+	"k8s.io/kubernetes/pkg/util/node"
 )
 
 // TODO: Break out the cloudprovider functionality out of core and only support the new flow
@@ -63,6 +64,7 @@ func ValidateMasterConfiguration(c *kubeadm.MasterConfiguration) field.ErrorList
 	allErrs = append(allErrs, ValidateNetworking(&c.Networking, field.NewPath("networking"))...)
 	allErrs = append(allErrs, ValidateAPIServerCertSANs(c.APIServerCertSANs, field.NewPath("cert-altnames"))...)
 	allErrs = append(allErrs, ValidateAbsolutePath(c.CertificatesDir, field.NewPath("certificates-dir"))...)
+	allErrs = append(allErrs, ValidateNodeName(c.NodeName, field.NewPath("node-name"))...)
 	allErrs = append(allErrs, ValidateToken(c.Token, field.NewPath("token"))...)
 	return allErrs
 }
@@ -237,6 +239,14 @@ func ValidateAbsolutePath(path string, fldPath *field.Path) field.ErrorList {
 	return allErrs
 }
 
+func ValidateNodeName(nodename string, fldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+	if node.GetHostname(nodename) != nodename {
+		allErrs = append(allErrs, field.Invalid(fldPath, nodename, "nodename is not valid, must be lower case"))
+	}
+	return allErrs
+}
+
 func ValidateCloudProvider(provider string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 	if len(provider) == 0 {

cmd/kubeadm/app/apis/kubeadm/validation/validation_test.go

@@ -78,6 +78,29 @@ func TestValidateAuthorizationModes(t *testing.T) {
 	}
 }
 
+func TestValidateNodeName(t *testing.T) {
+	var tests = []struct {
+		s        string
+		f        *field.Path
+		expected bool
+	}{
+		{"", nil, false},                 // ok if not provided
+		{"1234", nil, true},              // supported
+		{"valid-nodename", nil, true},    // supported
+		{"INVALID-NODENAME", nil, false}, // Upper cases is invalid
+	}
+	for _, rt := range tests {
+		actual := ValidateNodeName(rt.s, rt.f)
+		if (len(actual) == 0) != rt.expected {
+			t.Errorf(
+				"failed ValidateNodeName:\n\texpected: %t\n\t  actual: %t",
+				rt.expected,
+				(len(actual) == 0),
+			)
+		}
+	}
+}
+
 func TestValidateCloudProvider(t *testing.T) {
 	var tests = []struct {
 		s        string
@@ -177,6 +200,7 @@ func TestValidateIPNetFromString(t *testing.T) {
 }
 
 func TestValidateMasterConfiguration(t *testing.T) {
+	nodename := "valid-nodename"
 	var tests = []struct {
 		s        *kubeadm.MasterConfiguration
 		expected bool
@@ -189,6 +213,7 @@ func TestValidateMasterConfiguration(t *testing.T) {
 				DNSDomain:     "cluster.local",
 			},
 			CertificatesDir: "/some/cert/dir",
+			NodeName:        nodename,
 		}, false},
 		{&kubeadm.MasterConfiguration{
 			AuthorizationModes: []string{"Node", "RBAC"},
@@ -198,6 +223,7 @@ func TestValidateMasterConfiguration(t *testing.T) {
 			},
 			CertificatesDir: "/some/other/cert/dir",
 			Token:           "abcdef.0123456789abcdef",
+			NodeName:        nodename,
 		}, true},
 		{&kubeadm.MasterConfiguration{
 			AuthorizationModes: []string{"Node", "RBAC"},
@@ -206,6 +232,7 @@ func TestValidateMasterConfiguration(t *testing.T) {
 				DNSDomain:     "cluster.local",
 			},
 			CertificatesDir: "/some/cert/dir",
+			NodeName:        nodename,
 		}, false},
 		{&kubeadm.MasterConfiguration{
 			AuthorizationModes: []string{"Node", "RBAC"},
@@ -215,6 +242,7 @@ func TestValidateMasterConfiguration(t *testing.T) {
 			},
 			CertificatesDir: "/some/other/cert/dir",
 			Token:           "abcdef.0123456789abcdef",
+			NodeName:        nodename,
 		}, true},
 	}
 	for _, rt := range tests {

cmd/kubeadm/app/cmd/BUILD

@@ -45,6 +45,7 @@ go_library(
         "//pkg/printers:go_default_library",
         "//pkg/util/i18n:go_default_library",
         "//pkg/util/initsystem:go_default_library",
+        "//pkg/util/node:go_default_library",
         "//pkg/util/version:go_default_library",
         "//pkg/version:go_default_library",
         "//vendor/github.com/ghodss/yaml:go_default_library",

cmd/kubeadm/app/cmd/init.go

@@ -123,6 +123,10 @@ func NewCmdInit(out io.Writer) *cobra.Command {
 		&cfg.APIServerCertSANs, "apiserver-cert-extra-sans", cfg.APIServerCertSANs,
 		`Optional extra altnames to use for the API Server serving cert. Can be both IP addresses and dns names.`,
 	)
+	cmd.PersistentFlags().StringVar(
+		&cfg.NodeName, "node-name", cfg.NodeName,
+		`Specify the node name`,
+	)
 
 	cmd.PersistentFlags().StringVar(&cfgPath, "config", cfgPath, "Path to kubeadm config file (WARNING: Usage of a configuration file is experimental)")
 
@@ -220,7 +224,7 @@ func (i *Init) Run(out io.Writer) error {
 	// PHASE 2: Generate kubeconfig files for the admin and the kubelet
 
 	masterEndpoint := fmt.Sprintf("https://%s:%d", i.cfg.API.AdvertiseAddress, i.cfg.API.BindPort)
-	err = kubeconfigphase.CreateInitKubeConfigFiles(masterEndpoint, i.cfg.CertificatesDir, kubeadmapi.GlobalEnvParams.KubernetesDir)
+	err = kubeconfigphase.CreateInitKubeConfigFiles(masterEndpoint, i.cfg.CertificatesDir, kubeadmapi.GlobalEnvParams.KubernetesDir, i.cfg.NodeName)
 	if err != nil {
 		return err
 	}
@@ -236,7 +240,7 @@ func (i *Init) Run(out io.Writer) error {
 		return err
 	}
 
-	if err := apiconfigphase.UpdateMasterRoleLabelsAndTaints(client); err != nil {
+	if err := apiconfigphase.UpdateMasterRoleLabelsAndTaints(client, i.cfg.NodeName); err != nil {
 		return err
 	}
 

cmd/kubeadm/app/cmd/join.go

@@ -20,7 +20,6 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"os"
 	"path/filepath"
 
 	"github.com/renstrom/dedent"
@@ -33,11 +32,12 @@ import (
 	"k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/validation"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/discovery"
-	kubenode "k8s.io/kubernetes/cmd/kubeadm/app/node"
+	kubeadmnode "k8s.io/kubernetes/cmd/kubeadm/app/node"
 	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	kubeconfigutil "k8s.io/kubernetes/cmd/kubeadm/app/util/kubeconfig"
 	"k8s.io/kubernetes/pkg/api"
+	nodeutil "k8s.io/kubernetes/pkg/util/node"
 )
 
 var (
@@ -178,21 +178,16 @@ func (j *Join) Run(out io.Writer) error {
 		return err
 	}
 
-	hostname := j.cfg.NodeName
+	hostname := nodeutil.GetHostname(j.cfg.NodeName)
-	if hostname == "" {
+
-		hostname, err = os.Hostname()
-		if err != nil {
-			return err
-		}
-	}
 	client, err := kubeconfigutil.KubeConfigToClientSet(cfg)
 	if err != nil {
 		return err
 	}
-	if err := kubenode.ValidateAPIServer(client); err != nil {
+	if err := kubeadmnode.ValidateAPIServer(client); err != nil {
 		return err
 	}
-	if err := kubenode.PerformTLSBootstrap(cfg, hostname); err != nil {
+	if err := kubeadmnode.PerformTLSBootstrap(cfg, hostname); err != nil {
 		return err
 	}
 

cmd/kubeadm/app/phases/apiconfig/BUILD

@@ -45,7 +45,6 @@ go_library(
         "//pkg/apis/rbac/v1beta1:go_default_library",
         "//pkg/bootstrap/api:go_default_library",
         "//pkg/kubelet/apis:go_default_library",
-        "//pkg/util/node:go_default_library",
         "//pkg/util/version:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",
         "//vendor/k8s.io/api/rbac/v1beta1:go_default_library",

cmd/kubeadm/app/phases/apiconfig/setupmaster.go

@@ -30,20 +30,19 @@ import (
 	clientset "k8s.io/client-go/kubernetes"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	kubeletapis "k8s.io/kubernetes/pkg/kubelet/apis"
-	"k8s.io/kubernetes/pkg/util/node"
 )
 
 const apiCallRetryInterval = 500 * time.Millisecond
 
 // TODO: Can we think of any unit tests here? Or should this code just be covered through integration/e2e tests?
 
-func attemptToUpdateMasterRoleLabelsAndTaints(client *clientset.Clientset) error {
+func attemptToUpdateMasterRoleLabelsAndTaints(client *clientset.Clientset, nodeName string) error {
 	var n *v1.Node
 
 	// Wait for current node registration
 	wait.PollInfinite(kubeadmconstants.APICallRetryInterval, func() (bool, error) {
 		var err error
-		if n, err = client.Nodes().Get(node.GetHostname(""), metav1.GetOptions{}); err != nil {
+		if n, err = client.Nodes().Get(nodeName, metav1.GetOptions{}); err != nil {
 			return false, nil
 		}
 		// The node may appear to have no labels at first,
@@ -75,7 +74,7 @@ func attemptToUpdateMasterRoleLabelsAndTaints(client *clientset.Clientset) error
 		if apierrs.IsConflict(err) {
 			fmt.Println("[apiclient] Temporarily unable to update master node metadata due to conflict (will retry)")
 			time.Sleep(apiCallRetryInterval)
-			attemptToUpdateMasterRoleLabelsAndTaints(client)
+			attemptToUpdateMasterRoleLabelsAndTaints(client, nodeName)
 		} else {
 			return err
 		}
@@ -95,9 +94,9 @@ func addTaintIfNotExists(n *v1.Node, t v1.Taint) {
 }
 
 // UpdateMasterRoleLabelsAndTaints taints the master and sets the master label
-func UpdateMasterRoleLabelsAndTaints(client *clientset.Clientset) error {
+func UpdateMasterRoleLabelsAndTaints(client *clientset.Clientset, nodeName string) error {
 	// TODO: Use iterate instead of recursion
-	err := attemptToUpdateMasterRoleLabelsAndTaints(client)
+	err := attemptToUpdateMasterRoleLabelsAndTaints(client, nodeName)
 	if err != nil {
 		return fmt.Errorf("failed to update master node - [%v]", err)
 	}

cmd/kubeadm/app/phases/apiconfig/setupmaster_test.go

@@ -130,7 +130,7 @@ func TestUpdateMasterRoleLabelsAndTaints(t *testing.T) {
 			t.Fatalf("UpdateMasterRoleLabelsAndTaints(%s): unexpected error building clientset: %v", tc.name, err)
 		}
 
-		err = UpdateMasterRoleLabelsAndTaints(cs)
+		err = UpdateMasterRoleLabelsAndTaints(cs, hostname)
 		if err != nil {
 			t.Errorf("UpdateMasterRoleLabelsAndTaints(%s) returned unexpected error: %v", tc.name, err)
 		}

cmd/kubeadm/app/phases/certs/certs.go

@@ -21,7 +21,6 @@ import (
 	"crypto/x509"
 	"fmt"
 	"net"
-	"os"
 
 	"k8s.io/apimachinery/pkg/util/validation"
 	certutil "k8s.io/client-go/util/cert"
@@ -124,12 +123,6 @@ func NewFrontProxyClientCertAndKey(frontProxyCACert *x509.Certificate, frontProx
 // getAltNames builds an AltNames object for to be used when generating apiserver certificate
 func getAltNames(cfg *kubeadmapi.MasterConfiguration) (*certutil.AltNames, error) {
 
-	// host name
-	hostname, err := os.Hostname()
-	if err != nil {
-		return nil, fmt.Errorf("couldn't get the hostname: %v", err)
-	}
-
 	// advertise address
 	advertiseAddress := net.ParseIP(cfg.API.AdvertiseAddress)
 	if advertiseAddress == nil {
@@ -150,7 +143,7 @@ func getAltNames(cfg *kubeadmapi.MasterConfiguration) (*certutil.AltNames, error
 	// create AltNames with defaults DNSNames/IPs
 	altNames := &certutil.AltNames{
 		DNSNames: []string{
-			hostname,
+			cfg.NodeName,
 			"kubernetes",
 			"kubernetes.default",
 			"kubernetes.default.svc",

cmd/kubeadm/app/phases/certs/certs_test.go

@@ -19,7 +19,6 @@ package certs
 import (
 	"crypto/x509"
 	"net"
-	"os"
 	"testing"
 
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
@@ -36,14 +35,13 @@ func TestNewCACertAndKey(t *testing.T) {
 }
 
 func TestNewAPIServerCertAndKey(t *testing.T) {
-	hostname, err := os.Hostname()
+	hostname := "valid-hostname"
-	if err != nil {
+
-		t.Errorf("couldn't get the hostname: %v", err)
-	}
 	advertiseIP := "1.2.3.4"
 	cfg := &kubeadmapi.MasterConfiguration{
 		API:        kubeadmapi.API{AdvertiseAddress: advertiseIP},
 		Networking: kubeadmapi.Networking{ServiceSubnet: "10.96.0.0/12", DNSDomain: "cluster.local"},
+		NodeName:   "valid-hostname",
 	}
 	caCert, caKey, err := NewCACertAndKey()
 

cmd/kubeadm/app/phases/kubeconfig/BUILD

@@ -18,7 +18,6 @@ go_library(
         "//cmd/kubeadm/app/constants:go_default_library",
         "//cmd/kubeadm/app/phases/certs/pkiutil:go_default_library",
         "//cmd/kubeadm/app/util/kubeconfig:go_default_library",
-        "//pkg/util/node:go_default_library",
         "//vendor/k8s.io/client-go/tools/clientcmd:go_default_library",
         "//vendor/k8s.io/client-go/tools/clientcmd/api:go_default_library",
         "//vendor/k8s.io/client-go/util/cert:go_default_library",

cmd/kubeadm/app/phases/kubeconfig/kubeconfig.go

@@ -29,7 +29,6 @@ import (
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/phases/certs/pkiutil"
 	kubeconfigutil "k8s.io/kubernetes/cmd/kubeadm/app/util/kubeconfig"
-	"k8s.io/kubernetes/pkg/util/node"
 )
 
 // BuildConfigProperties holds some simple information about how this phase should build the KubeConfig object
@@ -53,12 +52,7 @@ type BuildConfigProperties struct {
 // /etc/kubernetes/{admin,kubelet}.conf exist but not certs => certs will be generated and conflict with the kubeconfig files => error
 
 // CreateInitKubeConfigFiles is called from the main init and does the work for the default phase behaviour
-func CreateInitKubeConfigFiles(masterEndpoint, pkiDir, outDir string) error {
+func CreateInitKubeConfigFiles(masterEndpoint, pkiDir, outDir, nodeName string) error {
-
-	nodeName := node.GetHostname("")
-	if len(nodeName) == 0 {
-		return fmt.Errorf("unable to get hostname for master node")
-	}
 
 	// Create a lightweight specification for what the files should look like
 	filesToCreateFromSpec := map[string]BuildConfigProperties{

cmd/kubeadm/app/preflight/BUILD

@@ -20,7 +20,6 @@ go_library(
         "//pkg/api/validation:go_default_library",
         "//pkg/kubeapiserver/authorizer/modes:go_default_library",
         "//pkg/util/initsystem:go_default_library",
-        "//pkg/util/node:go_default_library",
         "//plugin/cmd/kube-scheduler/app/options:go_default_library",
         "//test/e2e_node/system:go_default_library",
         "//vendor/github.com/PuerkitoBio/purell:go_default_library",

cmd/kubeadm/app/preflight/checks.go

@@ -46,7 +46,6 @@ import (
 	"k8s.io/kubernetes/pkg/api/validation"
 	authzmodes "k8s.io/kubernetes/pkg/kubeapiserver/authorizer/modes"
 	"k8s.io/kubernetes/pkg/util/initsystem"
-	"k8s.io/kubernetes/pkg/util/node"
 	schoptions "k8s.io/kubernetes/plugin/cmd/kube-scheduler/app/options"
 	"k8s.io/kubernetes/test/e2e_node/system"
 )
@@ -271,21 +270,22 @@ func (ipc InPathCheck) Check() (warnings, errors []error) {
 
 // HostnameCheck checks if hostname match dns sub domain regex.
 // If hostname doesn't match this regex, kubelet will not launch static pods like kube-apiserver/kube-controller-manager and so on.
-type HostnameCheck struct{}
+type HostnameCheck struct {
+	nodeName string
+}
 
 func (hc HostnameCheck) Check() (warnings, errors []error) {
 	errors = []error{}
 	warnings = []error{}
-	hostname := node.GetHostname("")
+	for _, msg := range validation.ValidateNodeName(hc.nodeName, false) {
-	for _, msg := range validation.ValidateNodeName(hostname, false) {
+		errors = append(errors, fmt.Errorf("hostname \"%s\" %s", hc.nodeName, msg))
-		errors = append(errors, fmt.Errorf("hostname \"%s\" %s", hostname, msg))
 	}
-	addr, err := net.LookupHost(hostname)
+	addr, err := net.LookupHost(hc.nodeName)
 	if addr == nil {
-		warnings = append(warnings, fmt.Errorf("hostname \"%s\" could not be reached", hostname))
+		warnings = append(warnings, fmt.Errorf("hostname \"%s\" could not be reached", hc.nodeName))
 	}
 	if err != nil {
-		warnings = append(warnings, fmt.Errorf("hostname \"%s\" %s", hostname, err))
+		warnings = append(warnings, fmt.Errorf("hostname \"%s\" %s", hc.nodeName, err))
 	}
 	return warnings, errors
 }
@@ -537,7 +537,7 @@ func RunInitMasterChecks(cfg *kubeadmapi.MasterConfiguration) error {
 	checks := []Checker{
 		SystemVerificationCheck{},
 		IsRootCheck{},
-		HostnameCheck{},
+		HostnameCheck{nodeName: cfg.NodeName},
 		ServiceCheck{Service: "kubelet", CheckIfActive: false},
 		ServiceCheck{Service: "docker", CheckIfActive: true},
 		FirewalldCheck{ports: []int{int(cfg.API.BindPort), 10250}},

cmd/kubeadm/app/util/config/BUILD

@@ -18,6 +18,7 @@ go_library(
         "//cmd/kubeadm/app/util:go_default_library",
         "//cmd/kubeadm/app/util/token:go_default_library",
         "//pkg/api:go_default_library",
+        "//pkg/util/node:go_default_library",
         "//pkg/util/version:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/net:go_default_library",

cmd/kubeadm/app/util/config/masterconfig.go

@@ -28,6 +28,7 @@ import (
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	tokenutil "k8s.io/kubernetes/cmd/kubeadm/app/util/token"
 	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/util/node"
 	"k8s.io/kubernetes/pkg/util/version"
 )
 
@@ -65,6 +66,8 @@ func SetInitDynamicDefaults(cfg *kubeadmapi.MasterConfiguration) error {
 		}
 	}
 
+	cfg.NodeName = node.GetHostname(cfg.NodeName)
+
 	return nil
 }