Merge pull request #50887 from netroby/patch-1

Automatic merge from submit-queue (batch tested with PRs 55016, 50887). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

If command.Execute() return err, print to stdErr

The current kube-proxy not print error if (execute() failed) . not so good and not so friendly to user.
If print err to stdError, will show us why it failed.

cmd/kube-proxy/proxy.go

@@ -18,6 +18,7 @@ package main
 
 import (
 	goflag "flag"
+	"fmt"
 	"os"
 
 	"github.com/spf13/pflag"
@@ -42,6 +43,7 @@ func main() {
 	defer logs.FlushLogs()
 
 	if err := command.Execute(); err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v\n", err)
 		os.Exit(1)
 	}
 }

cmd/kubeadm/kubeadm.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main
 
 import (
+	"fmt"
 	"os"
 
 	"k8s.io/kubernetes/cmd/kubeadm/app"
@@ -24,6 +25,7 @@ import (
 
 func main() {
 	if err := app.Run(); err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v\n", err)
 		os.Exit(1)
 	}
 	os.Exit(0)

cmd/kubectl/kubectl.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main
 
 import (
+	"fmt"
 	"os"
 
 	"k8s.io/kubernetes/cmd/kubectl/app"
@@ -24,6 +25,7 @@ import (
 
 func main() {
 	if err := app.Run(); err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v\n", err)
 		os.Exit(1)
 	}
 	os.Exit(0)