diff --git a/ray-operator/test/e2e/rayservice_ha_test.go b/ray-operator/test/e2e/rayservice_ha_test.go
index 140a93bedd..21583d68f6 100644
--- a/ray-operator/test/e2e/rayservice_ha_test.go
+++ b/ray-operator/test/e2e/rayservice_ha_test.go
@@ -2,9 +2,12 @@ package e2e
 
 import (
 	"testing"
+	"time"
 
 	. "github.com/onsi/gomega"
 
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
 	rayv1 "github.com/ray-project/kuberay/ray-operator/apis/ray/v1"
 	"github.com/ray-project/kuberay/ray-operator/controllers/ray/common"
 	. "github.com/ray-project/kuberay/ray-operator/test/support"
@@ -127,3 +130,73 @@ func TestAutoscalingRayService(t *testing.T) {
 	// Check the number of worker pods is correct when RayService is steady
 	g.Eventually(WorkerPods(test, rayServiceUnderlyingRayCluster), TestTimeoutLong).Should(HaveLen(numberOfPodsWhenSteady))
 }
+
+func TestRayServiceZeroDowntimeUpgrade(t *testing.T) {
+	rayserviceYamlFile := "testdata/rayservice.static.yaml"
+	locustYamlFile := "testdata/locust-cluster.const-rate.yaml"
+
+	test := With(t)
+	g := NewWithT(t)
+
+	// Create a namespace
+	namespace := test.NewTestNamespace()
+	test.StreamKubeRayOperatorLogs()
+
+	// Create a ConfigMap with Locust runner script
+	configMapAC := newConfigMap(namespace.Name, "locust-runner-script", files(test, "locust_runner.py"))
+	configMap, err := test.Client().Core().CoreV1().ConfigMaps(namespace.Name).Apply(test.Ctx(), configMapAC, TestApplyOptions)
+	g.Expect(err).NotTo(HaveOccurred())
+	test.T().Logf("Created ConfigMap %s/%s successfully", configMap.Namespace, configMap.Name)
+
+	// Create the RayService for testing
+	KubectlApplyYAML(test, rayserviceYamlFile, namespace.Name)
+	rayService, err := GetRayService(test, namespace.Name, "test-rayservice")
+	g.Expect(err).NotTo(HaveOccurred())
+	test.T().Logf("Created RayService %s/%s successfully", rayService.Namespace, rayService.Name)
+
+	test.T().Logf("Waiting for RayService %s/%s to running", rayService.Namespace, rayService.Name)
+	g.Eventually(RayService(test, rayService.Namespace, rayService.Name), TestTimeoutMedium).
+		Should(WithTransform(RayServiceStatus, Equal(rayv1.Running)))
+
+	// Create Locust RayCluster
+	KubectlApplyYAML(test, locustYamlFile, namespace.Name)
+	locustCluster, err := GetRayCluster(test, namespace.Name, "locust-cluster")
+	g.Expect(err).NotTo(HaveOccurred())
+	test.T().Logf("Created Locust RayCluster %s/%s successfully", locustCluster.Namespace, locustCluster.Name)
+
+	g.Eventually(RayCluster(test, locustCluster.Namespace, locustCluster.Name), TestTimeoutMedium).
+		Should(WithTransform(RayClusterState, Equal(rayv1.Ready)))
+	g.Expect(GetRayCluster(test, locustCluster.Namespace, locustCluster.Name)).To(WithTransform(RayClusterDesiredWorkerReplicas, Equal(int32(0))))
+
+	headPod, err := GetHeadPod(test, locustCluster)
+	g.Expect(err).NotTo(HaveOccurred())
+	test.T().Logf("Found head pod %s/%s", headPod.Namespace, headPod.Name)
+
+	// Install Locust in the head Pod
+	ExecPodCmd(test, headPod, common.RayHeadContainer, []string{"pip", "install", "locust"})
+
+	// Start a goroutine to perform zero-downtime upgrade
+	go func() {
+		test.T().Logf("Waiting several seconds before updating RayService")
+		time.Sleep(30 * time.Second)
+
+		test.T().Logf("Updating RayService")
+		rayService, err := GetRayService(test, namespace.Name, "test-rayservice")
+		g.Expect(err).NotTo(HaveOccurred())
+		rayClusterName := rayService.Status.ActiveServiceStatus.RayClusterName
+
+		newRayService := rayService.DeepCopy()
+		newRayService.Spec.RayClusterSpec.RayVersion = ""
+		newRayService, err = test.Client().Ray().RayV1().RayServices(newRayService.Namespace).Update(test.Ctx(), newRayService, metav1.UpdateOptions{})
+		g.Expect(err).NotTo(HaveOccurred())
+		// Assert that the active RayCluster is eventually different
+		g.Eventually(RayService(test, newRayService.Namespace, newRayService.Name), TestTimeoutShort).Should(WithTransform(func(rayService *rayv1.RayService) string {
+			return rayService.Status.ActiveServiceStatus.RayClusterName
+		}, Not(Equal(rayClusterName))))
+	}()
+
+	// Run Locust test
+	ExecPodCmd(test, headPod, common.RayHeadContainer, []string{
+		"python", "/locust-runner/locust_runner.py", "-f", "/locustfile/locustfile.py", "--host", "http://test-rayservice-serve-svc:8000",
+	})
+}
diff --git a/ray-operator/test/e2e/testdata/locust-cluster.const-rate.yaml b/ray-operator/test/e2e/testdata/locust-cluster.const-rate.yaml
index 12c99cb5e4..b4db382126 100644
--- a/ray-operator/test/e2e/testdata/locust-cluster.const-rate.yaml
+++ b/ray-operator/test/e2e/testdata/locust-cluster.const-rate.yaml
@@ -58,7 +58,7 @@ data:
 
     class StagesShape(LoadTestShape):
         stages = [
-            {"duration": 60, "users": 10, "spawn_rate": 10},
+            {"duration": 150, "users": 10, "spawn_rate": 10},
         ]
 
         def tick(self):