apiserver: use the identity value in the apiserver identity hash

Signed-off-by: Andrew Sy Kim <andrewsy@google.com>

test/e2e/apimachinery/apiserver_identity.go

@@ -27,6 +27,8 @@ import (
 	"time"
 
 	"github.com/onsi/ginkgo/v2"
+	"golang.org/x/crypto/cryptobyte"
+
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/wait"
@@ -124,7 +126,17 @@ var _ = SIGDescribe("kube-apiserver identity [Feature:APIServerIdentity]", func(
 			hostname, err := getControlPlaneHostname(ctx, &node)
 			framework.ExpectNoError(err)
 
-			hash := sha256.Sum256([]byte(hostname))
+			b := cryptobyte.NewBuilder(nil)
+			b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
+				b.AddBytes([]byte(hostname))
+			})
+			b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
+				b.AddBytes([]byte("kube-apiserver"))
+			})
+
+			hashData, err := b.Bytes()
+			framework.ExpectNoError(err)
+			hash := sha256.Sum256(hashData)
 			leaseName := "apiserver-" + strings.ToLower(base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(hash[:16]))
 
 			lease, err := client.CoordinationV1().Leases(metav1.NamespaceSystem).Get(context.TODO(), leaseName, metav1.GetOptions{})