kubeadm: fix reset error logging.

cmd/kubeadm/app/cmd/reset.go

@@ -144,7 +144,6 @@ func (r *Reset) Run(out io.Writer) error {
 }
 
 func drainAndRemoveNode(removeNode bool) error {
-
 	hostname, err := os.Hostname()
 	if err != nil {
 		return fmt.Errorf("failed to detect node hostname")
@@ -156,24 +155,26 @@ func drainAndRemoveNode(removeNode bool) error {
 
 	getNodesCmd := fmt.Sprintf("kubectl --kubeconfig %s get nodes | grep %s", kubeConfigPath, hostname)
 	output, err := exec.Command("sh", "-c", getNodesCmd).Output()
-	if err != nil || len(output) == 0 {
+	if err != nil {
 		// kubeadm shouldn't drain and/or remove the node when it doesn't exist anymore
-		return nil
+		return fmt.Errorf("failed to list nodes: %v", err)
+	}
+	if len(output) == 0 {
+		return fmt.Errorf("list nodes request returned zero entries")
 	}
 
 	fmt.Printf("[reset] Draining node: %q\n", hostname)
 
-	output, err = exec.Command("kubectl", "--kubeconfig", kubeConfigPath, "drain", hostname, "--delete-local-data", "--force", "--ignore-daemonsets").Output()
+	_, err = exec.Command("kubectl", "--kubeconfig", kubeConfigPath, "drain", hostname, "--delete-local-data", "--force", "--ignore-daemonsets").Output()
 	if err != nil {
-		return fmt.Errorf("failed to drain node %q [%s]", hostname, output)
+		return fmt.Errorf("failed to drain node %q: %v", hostname, err)
 	}
 
 	if removeNode {
 		fmt.Printf("[reset] Removing node: %q\n", hostname)
-
-		output, err = exec.Command("kubectl", "--kubeconfig", kubeConfigPath, "delete", "node", hostname).Output()
+		_, err = exec.Command("kubectl", "--kubeconfig", kubeConfigPath, "delete", "node", hostname).Output()
 		if err != nil {
-			return fmt.Errorf("failed to remove node %q [%s]", hostname, output)
+			return fmt.Errorf("failed to remove node %q: %v", hostname, err)
 		}
 	}