diff --git a/api/v1alpha1/etcdcluster_types.go b/api/v1alpha1/etcdcluster_types.go
index b61352a5..f7d35577 100644
--- a/api/v1alpha1/etcdcluster_types.go
+++ b/api/v1alpha1/etcdcluster_types.go
@@ -31,7 +31,8 @@ type EtcdClusterSpec struct {
 	// Replicas is the count of etcd instances in cluster.
 	// +optional
 	// +kubebuilder:default:=3
-	Replicas uint    `json:"replicas,omitempty"`
+	// +kubebuilder:validation:Minimum:=0
+	Replicas *int32  `json:"replicas,omitempty"`
 	Storage  Storage `json:"storage,omitempty"`
 }
 
diff --git a/api/v1alpha1/etcdcluster_webhook.go b/api/v1alpha1/etcdcluster_webhook.go
index 233531a9..9d8ca02a 100644
--- a/api/v1alpha1/etcdcluster_webhook.go
+++ b/api/v1alpha1/etcdcluster_webhook.go
@@ -42,9 +42,6 @@ var _ webhook.Defaulter = &EtcdCluster{}
 // Default implements webhook.Defaulter so a webhook will be registered for the type
 func (r *EtcdCluster) Default() {
 	etcdclusterlog.Info("default", "name", r.Name)
-	if r.Spec.Replicas == 0 {
-		r.Spec.Replicas = 3
-	}
 	if r.Spec.Storage.Size.IsZero() {
 		r.Spec.Storage.Size = resource.MustParse("4Gi")
 	}
@@ -67,11 +64,7 @@ func (r *EtcdCluster) ValidateUpdate(old runtime.Object) (admission.Warnings, er
 	if old.(*EtcdCluster).Spec.Replicas != r.Spec.Replicas {
 		warnings = append(warnings, "cluster resize is not currently supported")
 	}
-
-	if len(warnings) > 0 {
-		return warnings, nil
-	}
-	return nil, nil
+	return warnings, nil
 }
 
 // ValidateDelete implements webhook.Validator so a webhook will be registered for the type
diff --git a/api/v1alpha1/etcdcluster_webhook_test.go b/api/v1alpha1/etcdcluster_webhook_test.go
index b6a88ccd..674b0304 100644
--- a/api/v1alpha1/etcdcluster_webhook_test.go
+++ b/api/v1alpha1/etcdcluster_webhook_test.go
@@ -20,6 +20,7 @@ import (
 	. "github.com/onsi/ginkgo/v2"
 	"github.com/onsi/gomega"
 	"k8s.io/apimachinery/pkg/api/resource"
+	"k8s.io/utils/ptr"
 )
 
 var _ = Describe("EtcdCluster Webhook", func() {
@@ -28,14 +29,14 @@ var _ = Describe("EtcdCluster Webhook", func() {
 		It("Should fill in the default value if a required field is empty", func() {
 			etcdCluster := &EtcdCluster{}
 			etcdCluster.Default()
-			gomega.Expect(etcdCluster.Spec.Replicas).To(gomega.Equal(uint(3)))
+			gomega.Expect(etcdCluster.Spec.Replicas).To(gomega.BeNil(), "User should have an opportunity to create cluster with 0 replicas")
 			gomega.Expect(etcdCluster.Spec.Storage.Size).To(gomega.Equal(resource.MustParse("4Gi")))
 		})
 
 		It("Should not override fields with default values if not empty", func() {
 			etcdCluster := &EtcdCluster{
 				Spec: EtcdClusterSpec{
-					Replicas: 5,
+					Replicas: ptr.To(int32(5)),
 					Storage: Storage{
 						StorageClass: "local-path",
 						Size:         resource.MustParse("10Gi"),
@@ -43,25 +44,22 @@ var _ = Describe("EtcdCluster Webhook", func() {
 				},
 			}
 			etcdCluster.Default()
-			gomega.Expect(etcdCluster.Spec.Replicas).To(gomega.Equal(uint(5)))
+			gomega.Expect(*etcdCluster.Spec.Replicas).To(gomega.Equal(int32(5)))
 			gomega.Expect(etcdCluster.Spec.Storage.Size).To(gomega.Equal(resource.MustParse("10Gi")))
 		})
 	})
 
-	// Not yet applicable as currently all fields are optional.
-
-	//Context("When creating EtcdCluster under Validating Webhook", func() {
-	//	It("Should deny if a required field is empty", func() {
-	//
-	//		// TODO(user): Add your logic here
-	//
-	//	})
-	//
-	//	It("Should admit if all required fields are provided", func() {
-	//
-	//		// TODO(user): Add your logic here
-	//
-	//	})
-	//})
+	Context("When creating EtcdCluster under Validating Webhook", func() {
+		It("Should admit if all required fields are provided", func() {
+			etcdCluster := &EtcdCluster{
+				Spec: EtcdClusterSpec{
+					Replicas: ptr.To(int32(1)),
+				},
+			}
+			w, err := etcdCluster.ValidateCreate()
+			gomega.Expect(err).To(gomega.Succeed())
+			gomega.Expect(w).To(gomega.BeEmpty())
+		})
+	})
 
 })
diff --git a/api/v1alpha1/zz_generated.deepcopy.go b/api/v1alpha1/zz_generated.deepcopy.go
index e19f556d..e8f87f2b 100644
--- a/api/v1alpha1/zz_generated.deepcopy.go
+++ b/api/v1alpha1/zz_generated.deepcopy.go
@@ -87,6 +87,11 @@ func (in *EtcdClusterList) DeepCopyObject() runtime.Object {
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *EtcdClusterSpec) DeepCopyInto(out *EtcdClusterSpec) {
 	*out = *in
+	if in.Replicas != nil {
+		in, out := &in.Replicas, &out.Replicas
+		*out = new(int32)
+		**out = **in
+	}
 	in.Storage.DeepCopyInto(&out.Storage)
 }
 
diff --git a/config/crd/bases/etcd.aenix.io_etcdclusters.yaml b/config/crd/bases/etcd.aenix.io_etcdclusters.yaml
index 0f0a39ad..07cfb934 100644
--- a/config/crd/bases/etcd.aenix.io_etcdclusters.yaml
+++ b/config/crd/bases/etcd.aenix.io_etcdclusters.yaml
@@ -42,6 +42,8 @@ spec:
               replicas:
                 default: 3
                 description: Replicas is the count of etcd instances in cluster.
+                format: int32
+                minimum: 0
                 type: integer
               storage:
                 properties:
diff --git a/internal/controller/etcdcluster_controller.go b/internal/controller/etcdcluster_controller.go
index 112bdfc6..7732ac26 100644
--- a/internal/controller/etcdcluster_controller.go
+++ b/internal/controller/etcdcluster_controller.go
@@ -268,7 +268,7 @@ func (r *EtcdClusterReconciler) ensureClusterStateConfigMap(
 	// configmap does not exist, create with cluster state "new"
 	if errors.IsNotFound(err) {
 		initialCluster := ""
-		for i := uint(0); i < cluster.Spec.Replicas; i++ {
+		for i := int32(0); i < *cluster.Spec.Replicas; i++ {
 			if i > 0 {
 				initialCluster += ","
 			}
@@ -322,7 +322,7 @@ func (r *EtcdClusterReconciler) ensureClusterStatefulSet(
 			},
 			Spec: appsv1.StatefulSetSpec{
 				// initialize static fields that cannot be changed across updates.
-				Replicas:            new(int32),
+				Replicas:            cluster.Spec.Replicas,
 				ServiceName:         cluster.Name,
 				PodManagementPolicy: appsv1.ParallelPodManagement,
 				Selector: &metav1.LabelSelector{
@@ -442,7 +442,6 @@ func (r *EtcdClusterReconciler) ensureClusterStatefulSet(
 				},
 			},
 		}
-		*statefulSet.Spec.Replicas = int32(cluster.Spec.Replicas)
 		if err := ctrl.SetControllerReference(cluster, statefulSet, r.Scheme); err != nil {
 			return fmt.Errorf("cannot set controller reference: %w", err)
 		}
diff --git a/internal/controller/etcdcluster_controller_test.go b/internal/controller/etcdcluster_controller_test.go
index daf4cbaf..767e127a 100644
--- a/internal/controller/etcdcluster_controller_test.go
+++ b/internal/controller/etcdcluster_controller_test.go
@@ -19,6 +19,8 @@ package controller
 import (
 	"context"
 
+	"k8s.io/utils/ptr"
+
 	appsv1 "k8s.io/api/apps/v1"
 	v1 "k8s.io/api/core/v1"
 	resource2 "k8s.io/apimachinery/pkg/api/resource"
@@ -56,7 +58,7 @@ var _ = Describe("EtcdCluster Controller", func() {
 						Namespace: "default",
 					},
 					Spec: etcdaenixiov1alpha1.EtcdClusterSpec{
-						Replicas: 3,
+						Replicas: ptr.To(int32(3)),
 						Storage: etcdaenixiov1alpha1.Storage{
 							Size: resource2.MustParse("1Gi"),
 						},
@@ -142,8 +144,8 @@ var _ = Describe("EtcdCluster Controller", func() {
 			err = k8sClient.Get(ctx, typeNamespacedName, sts)
 			Expect(err).NotTo(HaveOccurred(), "cluster statefulset should exist")
 			// mark sts as ready
-			sts.Status.ReadyReplicas = int32(etcdcluster.Spec.Replicas)
-			sts.Status.Replicas = int32(etcdcluster.Spec.Replicas)
+			sts.Status.ReadyReplicas = *etcdcluster.Spec.Replicas
+			sts.Status.Replicas = *etcdcluster.Spec.Replicas
 			Expect(k8sClient.Status().Update(ctx, sts)).To(Succeed())
 			// reconcile and check EtcdCluster status
 			_, err = controllerReconciler.Reconcile(ctx, reconcile.Request{