diff --git a/ray-operator/apis/ray/v1/constant.go b/ray-operator/apis/ray/v1/constant.go
new file mode 100644
index 00000000000..fedf81a91f3
--- /dev/null
+++ b/ray-operator/apis/ray/v1/constant.go
@@ -0,0 +1,10 @@
+package v1
+
+// In KubeRay, the Ray container must be the first application container in a head or worker Pod.
+const RayContainerIndex = 0
+
+// Use as container env variable
+const RAY_REDIS_ADDRESS = "RAY_REDIS_ADDRESS"
+
+// Ray GCS FT related annotations
+const RayFTEnabledAnnotationKey = "ray.io/ft-enabled"
diff --git a/ray-operator/apis/ray/v1/raycluster_webhook.go b/ray-operator/apis/ray/v1/raycluster_webhook.go
index 1f9ac2f9022..37c663136a0 100644
--- a/ray-operator/apis/ray/v1/raycluster_webhook.go
+++ b/ray-operator/apis/ray/v1/raycluster_webhook.go
@@ -1,6 +1,7 @@
 package v1
 
 import (
+	"fmt"
 	"regexp"
 
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -19,8 +20,6 @@ var (
 	nameRegex, _  = regexp.Compile("^[a-z]([-a-z0-9]*[a-z0-9])?$")
 )
 
-const RayFTEnabledAnnotationKey = "ray.io/ft-enabled"
-
 func (r *RayCluster) SetupWebhookWithManager(mgr ctrl.Manager) error {
 	return ctrl.NewWebhookManagedBy(mgr).
 		For(r).
@@ -96,13 +95,22 @@ func (r *RayCluster) validateWorkerGroups() *field.Error {
 
 func (r *RayCluster) ValidateRayClusterSpec() *field.Error {
 	if r.Annotations[RayFTEnabledAnnotationKey] == "false" && r.Spec.GcsFaultToleranceOptions != nil {
-		return field.Invalid(field.NewPath("spec").Child("gcsFaultToleranceOptions"), r.Spec.GcsFaultToleranceOptions, "GcsFaultToleranceOptions should be nil when ray.io/ft-enabled is disabled")
+		return field.Invalid(
+			field.NewPath("spec").Child("gcsFaultToleranceOptions"),
+			r.Spec.GcsFaultToleranceOptions,
+			fmt.Sprintf("GcsFaultToleranceOptions should be nil when %s is disabled", RayFTEnabledAnnotationKey),
+		)
 	}
-	if r.Annotations[RayFTEnabledAnnotationKey] != "true" && r.Spec.HeadGroupSpec.Template.Spec.Containers[0].Env != nil {
-		for _, env := range r.Spec.HeadGroupSpec.Template.Spec.Containers[0].Env {
-			if env.Name == "RAY_REDIS_ADDRESS" {
-				return field.Invalid(field.NewPath("spec").Child("headGroupSpec").Child("template").Child("spec").Child("containers").Index(0).Child("env"), env.Name, "RAY_REDIS_ADDRESS should not be set when ray.io/ft-enabled is disabled")
-			}
+	if r.Annotations[RayFTEnabledAnnotationKey] != "true" &&
+		len(r.Spec.HeadGroupSpec.Template.Spec.Containers) > 0 &&
+		r.Spec.HeadGroupSpec.Template.Spec.Containers[RayContainerIndex].Env != nil {
+
+		if EnvVarExists(RAY_REDIS_ADDRESS, r.Spec.HeadGroupSpec.Template.Spec.Containers[RayContainerIndex].Env) {
+			return field.Invalid(
+				field.NewPath("spec").Child("headGroupSpec").Child("template").Child("spec").Child("containers").Index(0).Child("env"),
+				RAY_REDIS_ADDRESS,
+				fmt.Sprintf("%s should not be set when %s is disabled", RAY_REDIS_ADDRESS, RayFTEnabledAnnotationKey),
+			)
 		}
 	}
 	return nil
diff --git a/ray-operator/apis/ray/v1/raycluster_webhook_test.go b/ray-operator/apis/ray/v1/raycluster_webhook_test.go
index c30f62dba9f..f6150bc9166 100644
--- a/ray-operator/apis/ray/v1/raycluster_webhook_test.go
+++ b/ray-operator/apis/ray/v1/raycluster_webhook_test.go
@@ -1,6 +1,7 @@
 package v1
 
 import (
+	"fmt"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -26,7 +27,7 @@ func TestValidateRayClusterSpec(t *testing.T) {
 			},
 			gcsFaultToleranceOptions: &GcsFaultToleranceOptions{},
 			expectError:              true,
-			errorMessage:             "GcsFaultToleranceOptions should be nil when ray.io/ft-enabled is disabled",
+			errorMessage:             fmt.Sprintf("GcsFaultToleranceOptions should be nil when %s is disabled", RayFTEnabledAnnotationKey),
 		},
 		{
 			name: "FT disabled with RAY_REDIS_ADDRESS set",
@@ -35,24 +36,24 @@ func TestValidateRayClusterSpec(t *testing.T) {
 			},
 			envVars: []corev1.EnvVar{
 				{
-					Name:  "RAY_REDIS_ADDRESS",
+					Name:  RAY_REDIS_ADDRESS,
 					Value: "redis://127.0.0.1:6379",
 				},
 			},
 			expectError:  true,
-			errorMessage: "RAY_REDIS_ADDRESS should not be set when ray.io/ft-enabled is disabled",
+			errorMessage: fmt.Sprintf("%s should not be set when %s is disabled", RAY_REDIS_ADDRESS, RayFTEnabledAnnotationKey),
 		},
 		{
 			name:        "FT not set with RAY_REDIS_ADDRESS set",
 			annotations: map[string]string{},
 			envVars: []corev1.EnvVar{
 				{
-					Name:  "RAY_REDIS_ADDRESS",
+					Name:  RAY_REDIS_ADDRESS,
 					Value: "redis://127.0.0.1:6379",
 				},
 			},
 			expectError:  true,
-			errorMessage: "RAY_REDIS_ADDRESS should not be set when ray.io/ft-enabled is disabled",
+			errorMessage: fmt.Sprintf("%s should not be set when %s is disabled", RAY_REDIS_ADDRESS, RayFTEnabledAnnotationKey),
 		},
 		{
 			name: "FT disabled with other environment variables set",
@@ -104,7 +105,7 @@ func TestValidateRayClusterSpec(t *testing.T) {
 			},
 			envVars: []corev1.EnvVar{
 				{
-					Name:  "RAY_REDIS_ADDRESS",
+					Name:  RAY_REDIS_ADDRESS,
 					Value: "redis://127.0.0.1:6379",
 				},
 			},
@@ -196,7 +197,7 @@ func TestValidateRayCluster(t *testing.T) {
 			},
 			GcsFaultToleranceOptions: &GcsFaultToleranceOptions{},
 			expectError:              true,
-			errorMessage:             "GcsFaultToleranceOptions should be nil when ray.io/ft-enabled is disabled",
+			errorMessage:             fmt.Sprintf("GcsFaultToleranceOptions should be nil when %s is disabled", RayFTEnabledAnnotationKey),
 		},
 		{
 			name: "Valid RayCluster",
diff --git a/ray-operator/apis/ray/v1/utils.go b/ray-operator/apis/ray/v1/utils.go
new file mode 100644
index 00000000000..59dff801249
--- /dev/null
+++ b/ray-operator/apis/ray/v1/utils.go
@@ -0,0 +1,12 @@
+package v1
+
+import corev1 "k8s.io/api/core/v1"
+
+func EnvVarExists(envName string, envVars []corev1.EnvVar) bool {
+	for _, env := range envVars {
+		if env.Name == envName {
+			return true
+		}
+	}
+	return false
+}