Fix bug: [karmadactl init] can not read KUBECONFIG environment variable

Signed-off-by: lonelyCZ <531187475@qq.com>

pkg/karmadactl/cmdinit/kubernetes/deploy.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"os"
 	"path"
 	"strings"
 	"time"
@@ -70,10 +71,6 @@ type CommandInitOption struct {
 
 // Validate Check that there are enough flags to run the command.
 func (i *CommandInitOption) Validate(parentCommand string) error {
-	if !utils.PathIsExist(i.KubeConfig) {
-		return fmt.Errorf("kubeconfig file does not exist.absolute path to the kubeconfig file")
-	}
-
 	if i.EtcdStorageMode == "hostPath" && i.EtcdHostDataPath == "" {
 		return fmt.Errorf("when etcd storage mode is hostPath, dataPath is not empty. See '%s init --help'", parentCommand)
 	}
@@ -95,6 +92,16 @@ func (i *CommandInitOption) Validate(parentCommand string) error {
 
 // Complete Initialize k8s client
 func (i *CommandInitOption) Complete() error {
+	// check config path of host kubernetes cluster
+	env := os.Getenv("KUBECONFIG")
+	if env != "" {
+		i.KubeConfig = env
+	}
+
+	if !utils.PathIsExist(i.KubeConfig) {
+		return fmt.Errorf("kubeconfig file does not exist.absolute path to the kubeconfig file")
+	}
+
 	restConfig, err := utils.RestConfig(i.KubeConfig)
 	if err != nil {
 		return err