io/ioutil has already been deprecated in golang 1.16, so replace all ioutil with io and os

test/e2e_node/e2e_node_suite_test.go

@@ -27,7 +27,6 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"io/ioutil"
 
 	"math/rand"
 	"os"
@@ -260,7 +259,7 @@ func validateSystem() error {
 }
 
 func maskLocksmithdOnCoreos() {
-	data, err := ioutil.ReadFile("/etc/os-release")
+	data, err := os.ReadFile("/etc/os-release")
 	if err != nil {
 		// Not all distros contain this file.
 		klog.Infof("Could not read /etc/os-release: %v", err)
@@ -350,7 +349,7 @@ func getAPIServerClient() (*clientset.Clientset, error) {
 // loadSystemSpecFromFile returns the system spec from the file with the
 // filename.
 func loadSystemSpecFromFile(filename string) (*system.SysSpec, error) {
-	b, err := ioutil.ReadFile(filename)
+	b, err := os.ReadFile(filename)
 	if err != nil {
 		return nil, err
 	}