Fix: return error instead of os.Exit when something goes wrong

cmd/kube-scheduler/app/server.go

@@ -79,15 +79,14 @@ suitable Node. Multiple different schedulers may be used within a cluster;
 kube-scheduler is the reference implementation.
 See [scheduling](https://kubernetes.io/docs/concepts/scheduling-eviction/)
 for more information about scheduling and the kube-scheduler component.`,
-		Run: func(cmd *cobra.Command, args []string) {
+		RunE: func(cmd *cobra.Command, args []string) error {
 			if err := opts.Complete(&namedFlagSets); err != nil {
-				fmt.Fprintf(os.Stderr, "%v\n", err)
-				os.Exit(1)
+				return fmt.Errorf("completes the remaining instantiation of the options: %w", err)
 			}
 			if err := runCommand(cmd, opts, registryOptions...); err != nil {
-				fmt.Fprintf(os.Stderr, "%v\n", err)
-				os.Exit(1)
+				return fmt.Errorf("run command: %w", err)
 			}
+			return nil
 		},
 		Args: func(cmd *cobra.Command, args []string) error {
 			for _, arg := range args {

cmd/kube-scheduler/scheduler.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main
 
 import (
+	"fmt"
 	"math/rand"
 	"os"
 	"time"
@@ -32,6 +33,13 @@ import (
 )
 
 func main() {
+	if err := runSchedulerCmd(); err != nil {
+		fmt.Fprintf(os.Stderr, "failed to run scheduler command: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func runSchedulerCmd() error {
 	rand.Seed(time.Now().UnixNano())
 
 	pflag.CommandLine.SetNormalizeFunc(cliflag.WordSepNormalizeFunc)
@@ -42,6 +50,8 @@ func main() {
 	defer logs.FlushLogs()
 
 	if err := command.Execute(); err != nil {
-		os.Exit(1)
+		return fmt.Errorf("execute command: %w", err)
 	}
+
+	return nil
 }