kubeadm: fix unit test requiring admin.conf and root

cmd/kubeadm/app/cmd/BUILD

@@ -87,6 +87,7 @@ go_test(
         "//cmd/kubeadm/app/constants:go_default_library",
         "//cmd/kubeadm/app/util:go_default_library",
         "//cmd/kubeadm/app/util/config:go_default_library",
+        "//cmd/kubeadm/app/util/kubeconfig:go_default_library",
         "//cmd/kubeadm/app/util/output:go_default_library",
         "//cmd/kubeadm/app/util/runtime:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",

cmd/kubeadm/app/cmd/join.go

@@ -213,7 +213,7 @@ func NewCmdJoin(out io.Writer, joinOptions *joinOptions) *cobra.Command {
 	// sets the data builder function, that will be used by the runner
 	// both when running the entire workflow or single phases
 	joinRunner.SetDataInitializer(func(cmd *cobra.Command, args []string) (workflow.RunData, error) {
-		return newJoinData(cmd, args, joinOptions, out)
+		return newJoinData(cmd, args, joinOptions, out, kubeadmconstants.GetAdminKubeConfigPath())
 	})
 
 	// binds the Runner to kubeadm join command by altering
@@ -315,7 +315,7 @@ func newJoinOptions() *joinOptions {
 // newJoinData returns a new joinData struct to be used for the execution of the kubeadm join workflow.
 // This func takes care of validating joinOptions passed to the command, and then it converts
 // options into the internal JoinConfiguration type that is used as input all the phases in the kubeadm join workflow
-func newJoinData(cmd *cobra.Command, args []string, opt *joinOptions, out io.Writer) (*joinData, error) {
+func newJoinData(cmd *cobra.Command, args []string, opt *joinOptions, out io.Writer, adminKubeConfigPath string) (*joinData, error) {
 
 	// Validate the mixed arguments with --config and return early on errors
 	if err := validation.ValidateMixedArguments(cmd.Flags()); err != nil {
@@ -379,7 +379,6 @@ func newJoinData(cmd *cobra.Command, args []string, opt *joinOptions, out io.Wri
 
 	// if the admin.conf file already exists, use it for skipping the discovery process.
 	// NB. this case can happen when we are joining a control-plane node only (and phases are invoked atomically)
-	var adminKubeConfigPath = kubeadmconstants.GetAdminKubeConfigPath()
 	var tlsBootstrapCfg *clientcmdapi.Config
 	if _, err := os.Stat(adminKubeConfigPath); err == nil && opt.controlPlane {
 		// use the admin.conf as tlsBootstrapCfg, that is the kubeconfig file used for reading the kubeadm-config during discovery

cmd/kubeadm/app/cmd/join_test.go

@@ -24,6 +24,7 @@ import (
 
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
+	kubeconfigutil "k8s.io/kubernetes/cmd/kubeadm/app/util/kubeconfig"
 )
 
 const (
@@ -51,6 +52,11 @@ func TestNewJoinData(t *testing.T) {
 	}
 	defer os.RemoveAll(tmpDir)
 
+	// create kubeconfig
+	kubeconfigFilePath := filepath.Join(tmpDir, "test-kubeconfig-file")
+	kubeconfig := kubeconfigutil.CreateBasic("", "", "", []byte{})
+	kubeconfigutil.WriteToDisk(kubeconfigFilePath, kubeconfig)
+
 	// create config file
 	configFilePath := filepath.Join(tmpDir, "test-config-file")
 	cfgFile, err := os.Create(configFilePath)
@@ -257,7 +263,7 @@ func TestNewJoinData(t *testing.T) {
 			}
 
 			// test newJoinData method
-			data, err := newJoinData(cmd, tc.args, joinOptions, nil)
+			data, err := newJoinData(cmd, tc.args, joinOptions, nil, kubeconfigFilePath)
 			if err != nil && !tc.expectError {
 				t.Fatalf("newJoinData returned unexpected error: %v", err)
 			}