[RayCluster] Make headpod name deterministic

kubectl-plugin/test/e2e/kubectl_ray_log_test.go

@@ -29,7 +29,7 @@ var _ = Describe("Calling ray plugin `log` command on Ray Cluster", func() {
 
 	It("succeed in retrieving all ray cluster logs", func() {
 		expectedDirPath := "./raycluster-kuberay"
-		expectedOutputStringFormat := `No output directory specified, creating dir under current directory using resource name\.\nCommand set to retrieve both head and worker node logs\.\nDownloading log for Ray Node raycluster-kuberay-head-\w+\nDownloading log for Ray Node raycluster-kuberay-workergroup-worker-\w+`
+		expectedOutputStringFormat := `No output directory specified, creating dir under current directory using resource name\.\nCommand set to retrieve both head and worker node logs\.\nDownloading log for Ray Node raycluster-kuberay-head\nDownloading log for Ray Node raycluster-kuberay-workergroup-worker-\w+`
 
 		cmd := exec.Command("kubectl", "ray", "log", "--namespace", namespace, "raycluster-kuberay", "--node-type", "all")
 		output, err := cmd.CombinedOutput()
@@ -84,7 +84,7 @@ var _ = Describe("Calling ray plugin `log` command on Ray Cluster", func() {
 
 	It("succeed in retrieving ray cluster head logs", func() {
 		expectedDirPath := "./raycluster-kuberay"
-		expectedOutputStringFormat := `No output directory specified, creating dir under current directory using resource name\.\nCommand set to retrieve only head node logs\.\nDownloading log for Ray Node raycluster-kuberay-head-\w+`
+		expectedOutputStringFormat := `No output directory specified, creating dir under current directory using resource name\.\nCommand set to retrieve only head node logs\.\nDownloading log for Ray Node raycluster-kuberay-head`
 
 		cmd := exec.Command("kubectl", "ray", "log", "--namespace", namespace, "raycluster-kuberay", "--node-type", "head")
 		output, err := cmd.CombinedOutput()
@@ -191,7 +191,7 @@ var _ = Describe("Calling ray plugin `log` command on Ray Cluster", func() {
 
 	It("succeed in retrieving ray cluster logs within designated directory", func() {
 		expectedDirPath := "./temporary-directory"
-		expectedOutputStringFormat := `Command set to retrieve both head and worker node logs\.\nDownloading log for Ray Node raycluster-kuberay-head-\w+\nDownloading log for Ray Node raycluster-kuberay-workergroup-worker-\w+`
+		expectedOutputStringFormat := `Command set to retrieve both head and worker node logs\.\nDownloading log for Ray Node raycluster-kuberay-head\nDownloading log for Ray Node raycluster-kuberay-workergroup-worker-\w+`
 
 		err := os.MkdirAll(expectedDirPath, 0o755)
 		Expect(err).NotTo(HaveOccurred())

ray-operator/controllers/ray/common/pod.go

@@ -165,7 +165,7 @@ func DefaultHeadPodTemplate(ctx context.Context, instance rayv1.RayCluster, head
 	// headPort is passed into setMissingRayStartParams but unused there for the head pod.
 	// To mitigate this awkwardness and reduce code redundancy, unify head and worker pod configuration logic.
 	podTemplate := headSpec.Template
-	podTemplate.GenerateName = podName
+	podTemplate.Name = podName
 	// Pods created by RayCluster should be restricted to the namespace of the RayCluster.
 	// This ensures privilege of KubeRay users are contained within the namespace of the RayCluster.
 	podTemplate.ObjectMeta.Namespace = instance.Namespace

ray-operator/controllers/ray/raycluster_controller.go

@@ -733,24 +733,18 @@ func (r *RayClusterReconciler) reconcilePods(ctx context.Context, instance *rayv
 			return errstd.Join(utils.ErrFailedCreateHeadPod, err)
 		}
 		common.SuccessfulClustersCounterInc(instance.Namespace)
-	} else if len(headPods.Items) > 1 {
-		logger.Info("reconcilePods: Found more than one head Pods; deleting extra head Pods.", "nHeadPods", len(headPods.Items))
-		// TODO (kevin85421): In-place update may not be a good idea.
-		itemLength := len(headPods.Items)
-		for index := 0; index < itemLength; index++ {
-			if headPods.Items[index].Status.Phase == corev1.PodRunning || headPods.Items[index].Status.Phase == corev1.PodPending {
-				headPods.Items[index] = headPods.Items[len(headPods.Items)-1] // Replace healthy pod at index i with the last element from the list of pods to delete.
-				headPods.Items = headPods.Items[:len(headPods.Items)-1]       // Truncate slice.
-				itemLength--
-			}
-		}
-		// delete all the extra head pod pods
-		for _, extraHeadPodToDelete := range headPods.Items {
-			if err := r.Delete(ctx, &extraHeadPodToDelete); err != nil {
-				return errstd.Join(utils.ErrFailedDeleteHeadPod, err)
-			}
-			r.rayClusterScaleExpectation.ExpectScalePod(extraHeadPodToDelete.Namespace, instance.Name, expectations.HeadGroup, extraHeadPodToDelete.Name, expectations.Delete)
+	} else if len(headPods.Items) > 1 { // This should never happen. This protects against the case that users manually create headpod.
+		correctHeadPodName := instance.Name + "-head"
+		headPodNames := make([]string, len(headPods.Items))
+		for i, pod := range headPods.Items {
+			headPodNames[i] = pod.Name
 		}
+
+		logger.Info("Multiple head pods found, it should only exist one head pod. Please delete extra head pods.",
+			"found pods", headPodNames,
+			"should only leave", correctHeadPodName,
+		)
+		return fmt.Errorf("%d head pods found %v. Please delete extra head pods and leave only the head pod with name %s", len(headPods.Items), headPodNames, correctHeadPodName)
 	}
 
 	// Reconcile worker pods now
@@ -1092,7 +1086,7 @@ func (r *RayClusterReconciler) createWorkerPod(ctx context.Context, instance ray
 // Build head instance pod(s).
 func (r *RayClusterReconciler) buildHeadPod(ctx context.Context, instance rayv1.RayCluster) corev1.Pod {
 	logger := ctrl.LoggerFrom(ctx)
-	podName := utils.PodGenerateName(instance.Name, rayv1.HeadNode)
+	podName := utils.PodName(instance.Name, rayv1.HeadNode, false)
 	fqdnRayIP := utils.GenerateFQDNServiceName(ctx, instance, instance.Namespace) // Fully Qualified Domain Name
 	// The Ray head port used by workers to connect to the cluster (GCS server port for Ray >= 1.11.0, Redis port for older Ray.)
 	headPort := common.GetHeadPort(instance.Spec.HeadGroupSpec.RayStartParams)
@@ -1119,7 +1113,7 @@ func getCreatorCRDType(instance rayv1.RayCluster) utils.CRDType {
 // Build worker instance pods.
 func (r *RayClusterReconciler) buildWorkerPod(ctx context.Context, instance rayv1.RayCluster, worker rayv1.WorkerGroupSpec) corev1.Pod {
 	logger := ctrl.LoggerFrom(ctx)
-	podName := utils.PodGenerateName(fmt.Sprintf("%s-%s", instance.Name, worker.GroupName), rayv1.WorkerNode)
+	podName := utils.PodName(fmt.Sprintf("%s-%s", instance.Name, worker.GroupName), rayv1.WorkerNode, true)
 	fqdnRayIP := utils.GenerateFQDNServiceName(ctx, instance, instance.Namespace) // Fully Qualified Domain Name
 
 	// The Ray head port used by workers to connect to the cluster (GCS server port for Ray >= 1.11.0, Redis port for older Ray.)

ray-operator/controllers/ray/utils/util.go

@@ -165,10 +165,10 @@ func CheckRouteName(ctx context.Context, s string, n string) string {
 	return CheckName(s)
 }
 
-// PodGenerateName returns the value that should be used for a Pod's generateName
+// PodName returns the value that should be used for a Pod's Name or GenerateName
 // based on the RayCluster name and node type (head or worker).
-func PodGenerateName(prefix string, nodeType rayv1.RayNodeType) string {
-	maxPrefixLength := 50 // 63 - (max(8,6) + 5 ) // 6 to 8 char are consumed at the end with "-head-" or -worker- + 5 generated.
+func PodName(prefix string, nodeType rayv1.RayNodeType, isGenerateName bool) string {
+	maxPrefixLength := 50 // 63 - ( 8 + 5 ) // 8 char are consumed at the end with "-worker-" + 5 generated.
 
 	var podPrefix string
 	if len(prefix) <= maxPrefixLength {
@@ -177,7 +177,11 @@ func PodGenerateName(prefix string, nodeType rayv1.RayNodeType) string {
 		podPrefix = prefix[:maxPrefixLength]
 	}
 
-	return strings.ToLower(podPrefix + DashSymbol + string(nodeType) + DashSymbol)
+	result := strings.ToLower(podPrefix + DashSymbol + string(nodeType))
+	if isGenerateName {
+		result += DashSymbol
+	}
+	return result
 }
 
 // CheckName makes sure the name does not start with a numeric value and the total length is < 63 char

ray-operator/controllers/ray/utils/util_test.go

@@ -103,7 +103,7 @@ func TestCheckAllPodsRunning(t *testing.T) {
 	}
 }
 
-func TestPodGenerateName(t *testing.T) {
+func TestPodName(t *testing.T) {
 	tests := []struct {
 		name     string
 		prefix   string
@@ -114,7 +114,7 @@ func TestPodGenerateName(t *testing.T) {
 			name:     "short cluster name, head pod",
 			prefix:   "ray-cluster-01",
 			nodeType: rayv1.HeadNode,
-			expected: "ray-cluster-01-head-",
+			expected: "ray-cluster-01-head",
 		},
 		{
 			name:     "short cluster name, worker pod",
@@ -126,7 +126,7 @@ func TestPodGenerateName(t *testing.T) {
 			name:     "long cluster name, head pod",
 			prefix:   "ray-cluster-0000000000000000000000011111111122222233333333333333",
 			nodeType: rayv1.HeadNode,
-			expected: "ray-cluster-00000000000000000000000111111111222222-head-",
+			expected: "ray-cluster-00000000000000000000000111111111222222-head",
 		},
 		{
 			name:     "long cluster name, worker pod",
@@ -138,11 +138,12 @@ func TestPodGenerateName(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			str := PodGenerateName(test.prefix, test.nodeType)
+			isPodNameGenerated := test.nodeType == rayv1.WorkerNode // HeadPod name is now fixed
+			str := PodName(test.prefix, test.nodeType, isPodNameGenerated)
 			if str != test.expected {
 				t.Logf("expected: %q", test.expected)
 				t.Logf("actual: %q", str)
-				t.Error("PodGenerateName returned an unexpected string")
+				t.Error("PodName returned an unexpected string")
 			}
 
 			// 63 (max pod name length) - 5 random hexadecimal characters from generateName

ray-operator/test/e2e/raycluster_gcs_ft_test.go

@@ -109,14 +109,16 @@ func TestRayClusterGCSFaultTolerence(t *testing.T) {
 		err = test.Client().Core().CoreV1().Pods(namespace.Name).Delete(test.Ctx(), headPod.Name, metav1.DeleteOptions{})
 		g.Expect(err).NotTo(HaveOccurred())
 
-		testPodNameChanged := func(p *corev1.Pod) bool { return p.Name != headPod.Name }
+		PodUID := func(p *corev1.Pod) string { return string(p.UID) }
 		g.Eventually(HeadPod(test, rayCluster), TestTimeoutMedium).
-			Should(WithTransform(testPodNameChanged, Equal(true)))
+			ShouldNot(WithTransform(PodUID, Equal(string(headPod.UID)))) // Use UID to check if the new head pod is created.
 
 		g.Eventually(HeadPod(test, rayCluster), TestTimeoutMedium).
 			Should(WithTransform(PodState, Equal("Running")))
 
-		headPod, _ = GetHeadPod(test, rayCluster)
+		headPod, err = GetHeadPod(test, rayCluster) // Replace the old head pod
+		g.Expect(err).NotTo(HaveOccurred())
+
 		expectedOutput = "4"
 
 		ExecPodCmd(test, headPod, common.RayHeadContainer, []string{"python", "samples/test_detached_actor_2.py", rayNamespace, expectedOutput})

ray-operator/test/e2erayservice/rayservice_redeploy_test.go

@@ -71,7 +71,7 @@ func TestRedeployRayServe(t *testing.T) {
 		g.Expect(err).NotTo(HaveOccurred())
 		g.Expect(endpoints.Subsets).To(HaveLen(1))
 		g.Expect(endpoints.Subsets[0].Addresses).To(HaveLen(1))
-		g.Expect(endpoints.Subsets[0].Addresses[0].TargetRef.Name).NotTo(Equal(oldHeadPod.Name))
+		g.Expect(endpoints.Subsets[0].Addresses[0].TargetRef.UID).NotTo(Equal(oldHeadPod.UID))
 	}, TestTimeoutMedium).Should(Succeed())
 
 	test.T().Logf("Waiting for RayService %s/%s to running", rayService.Namespace, rayService.Name)