Replace hardcoded nginx:alpine with nginxAlpineImage constant

Refactor test file to use the existing nginxAlpineImage constant
instead of hardcoded strings for consistency with other parts of
the codebase.

Co-authored-by: Copilot <[email protected]>

Author: katara-Jayprakash

test/e2e/controller-manager/model_serving_test.go

@@ -1383,9 +1383,9 @@ func TestModelServingPartitionBoundaryProtection(t *testing.T) {
 
 	// Trigger rolling update by changing image
 	updatedMS := initialMS.DeepCopy()
-	updatedMS.Spec.Template.Roles[0].EntryTemplate.Spec.Containers[0].Image = "nginx:alpine"
+	updatedMS.Spec.Template.Roles[0].EntryTemplate.Spec.Containers[0].Image = nginxAlpineImage
 
-	t.Log("Updating ModelServing image to nginx:alpine (partition=3 protects R-0, R-1, R-2)")
+	t.Logf("Updating ModelServing image to %s (partition=3 protects R-0, R-1, R-2)", nginxAlpineImage)
 	_, err = kthenaClient.WorkloadV1alpha1().ModelServings(testNamespace).Update(ctx, updatedMS, metav1.UpdateOptions{})
 	require.NoError(t, err, "Failed to update ModelServing")
 
@@ -1419,7 +1419,7 @@ func TestModelServingPartitionBoundaryProtection(t *testing.T) {
 	t.Log("Verifying per-ordinal revisions and images")
 	labelSelector := modelServingLabelSelector(modelServing.Name)
 	waitForPodsByLabel(t, ctx, kubeClient, labelSelector, 3*time.Minute, func(pods []corev1.Pod) bool {
-		protectedCorrect, updatedCorrect := verifyPartitionState(t, pods, int(partition), nginxImage, "nginx:alpine")
+		protectedCorrect, updatedCorrect := verifyPartitionState(t, pods, int(partition), nginxImage, nginxAlpineImage)
 		t.Logf("Protected correct: %d/3, Updated correct: %d/2", protectedCorrect, updatedCorrect)
 		return protectedCorrect == 3 && updatedCorrect == 2
 	}, "Per-ordinal revision/image verification failed")
@@ -1449,9 +1449,9 @@ func TestModelServingPartitionDeletedGroupHistoricalRevision(t *testing.T) {
 
 	// Phase 2: Trigger partitioned update (change image)
 	updatedMS := initialMS.DeepCopy()
-	updatedMS.Spec.Template.Roles[0].EntryTemplate.Spec.Containers[0].Image = "nginx:alpine"
+	updatedMS.Spec.Template.Roles[0].EntryTemplate.Spec.Containers[0].Image = nginxAlpineImage
 
-	t.Log("Phase 2: Updating image to nginx:alpine (partition=3 protects R-0, R-1, R-2)")
+	t.Logf("Phase 2: Updating image to %s (partition=3 protects R-0, R-1, R-2)", nginxAlpineImage)
 	_, err = kthenaClient.WorkloadV1alpha1().ModelServings(testNamespace).Update(ctx, updatedMS, metav1.UpdateOptions{})
 	require.NoError(t, err, "Failed to update ModelServing")
 
@@ -1472,7 +1472,7 @@ func TestModelServingPartitionDeletedGroupHistoricalRevision(t *testing.T) {
 	// Verify the partitioned state is established: R-0,R-1,R-2 have old image, R-3,R-4 have new
 	labelSelector := modelServingLabelSelector(modelServing.Name)
 	waitForPodsByLabel(t, ctx, kubeClient, labelSelector, 3*time.Minute, func(pods []corev1.Pod) bool {
-		protectedOld, updatedNew := verifyPartitionState(t, pods, int(partition), nginxImage, "nginx:alpine")
+		protectedOld, updatedNew := verifyPartitionState(t, pods, int(partition), nginxImage, nginxAlpineImage)
 		return protectedOld == 3 && updatedNew == 2
 	}, "Failed to reach partitioned state")
 
@@ -1562,7 +1562,7 @@ func TestModelServingPartitionDeletedGroupHistoricalRevision(t *testing.T) {
 	// Also verify the overall state is still correct: 3 protected + 2 updated
 	t.Log("Verifying overall partition state is preserved after pod recreation")
 	waitForPodsByLabel(t, ctx, kubeClient, labelSelector, 3*time.Minute, func(pods []corev1.Pod) bool {
-		protectedOld, updatedNew := verifyPartitionState(t, pods, int(partition), nginxImage, "nginx:alpine")
+		protectedOld, updatedNew := verifyPartitionState(t, pods, int(partition), nginxImage, nginxAlpineImage)
 		t.Logf("Protected with old image: %d/3, Updated with new image: %d/2", protectedOld, updatedNew)
 		return protectedOld == 3 && updatedNew == 2
 	}, "Overall partition state broken after pod recreation")
@@ -1591,9 +1591,9 @@ func TestModelServingRollingUpdate(t *testing.T) {
 
 	// Trigger rolling update by changing image
 	updatedMS := initialMS.DeepCopy()
-	updatedMS.Spec.Template.Roles[0].EntryTemplate.Spec.Containers[0].Image = "nginx:alpine"
+	updatedMS.Spec.Template.Roles[0].EntryTemplate.Spec.Containers[0].Image = nginxAlpineImage
 
-	t.Log("Triggering rolling update: image -> nginx:alpine (no partition, all replicas should update)")
+	t.Logf("Triggering rolling update: image -> %s (no partition, all replicas should update)", nginxAlpineImage)
 	_, err = kthenaClient.WorkloadV1alpha1().ModelServings(testNamespace).Update(ctx, updatedMS, metav1.UpdateOptions{})
 	require.NoError(t, err, "Failed to update ModelServing")
 
@@ -1622,7 +1622,7 @@ func TestModelServingRollingUpdate(t *testing.T) {
 			containerImage := getPodContainerImage(pod, "test-container")
 			podRevision := pod.Labels["modelserving.volcano.sh/revision"]
 
-			if containerImage != "nginx:alpine" {
+			if containerImage != nginxAlpineImage {
 				t.Logf("Pod %s still has old image: %s", pod.Name, containerImage)
 				allCorrect = false
 			}
@@ -1660,7 +1660,7 @@ func TestModelServingRollingUpdate(t *testing.T) {
 
 			containerImage := getPodContainerImage(pod, "test-container")
 			podRevision := pod.Labels["modelserving.volcano.sh/revision"]
-			if containerImage != "nginx:alpine" || podRevision != finalMS.Status.CurrentRevision {
+			if containerImage != nginxAlpineImage || podRevision != finalMS.Status.CurrentRevision {
 				return false
 			}
 		}