diff --git a/cmd/e2e/upgrade_test.go b/cmd/e2e/upgrade_test.go
index da3d4b8..99663bc 100644
--- a/cmd/e2e/upgrade_test.go
+++ b/cmd/e2e/upgrade_test.go
@@ -13,7 +13,10 @@ func TestEDSUpgradingEDS(t *testing.T) {
 	eds := verifyEDS(t, edsName, edsSpec, edsSpec.Replicas)
 	eds.Spec.Template.Labels["new-label"] = "hello"
 
-	err := updateEDS(edsName, eds)
+	var err error
+	eds, err = waitForEDS(t, edsName)
+	require.NoError(t, err)
+	err = updateEDS(edsName, eds)
 	require.NoError(t, err)
 
 	verifyEDS(t, edsName, eds.Spec, eds.Spec.Replicas)
diff --git a/operator/elasticsearch.go b/operator/elasticsearch.go
index 5714a9a..1a65531 100644
--- a/operator/elasticsearch.go
+++ b/operator/elasticsearch.go
@@ -491,6 +491,33 @@ func (r *EDSResource) OnStableReplicasHook(ctx context.Context) error {
 	return r.esClient.Cleanup(ctx)
 }
 
+// UpdateStatus updates the status of the EDS to set the current replicas from
+// StatefulSet and updating the observedGeneration.
+func (r *EDSResource) UpdateStatus(sts *appsv1.StatefulSet) error {
+	observedGeneration := int64(0)
+	if r.eds.Status.ObservedGeneration != nil {
+		observedGeneration = *r.eds.Status.ObservedGeneration
+	}
+
+	replicas := int32(0)
+	if sts.Spec.Replicas != nil {
+		replicas = *sts.Spec.Replicas
+	}
+
+	if r.eds.Generation != observedGeneration ||
+		r.eds.Status.Replicas != replicas {
+		r.eds.Status.Replicas = replicas
+		r.eds.Status.ObservedGeneration = &r.eds.Generation
+		var err error
+		r.eds, err = r.kube.ZalandoV1().ElasticsearchDataSets(r.eds.Namespace).UpdateStatus(r.eds)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func (r *EDSResource) applyScalingOperation() error {
 	operation, err := edsScalingOperation(r.eds)
 	if err != nil {
@@ -781,7 +808,7 @@ func (o *ElasticsearchOperator) scaleEDS(eds *zv1.ElasticsearchDataSet, es *ESRe
 			return err
 		}
 
-		if  scalingOperation.ScalingDirection != NONE {
+		if scalingOperation.ScalingDirection != NONE {
 			eds.Annotations[esScalingOperationKey] = string(jsonBytes)
 
 			// persist changes of EDS
diff --git a/operator/operator.go b/operator/operator.go
index e015201..8258227 100644
--- a/operator/operator.go
+++ b/operator/operator.go
@@ -68,6 +68,11 @@ type StatefulResource interface {
 	// EnsureResources
 	EnsureResources() error
 
+	// UpdateStatus updates the status of the StatefulResource. The
+	// statefulset is parsed to provide additional information like
+	// replicas to the status.
+	UpdateStatus(sts *appsv1.StatefulSet) error
+
 	// PreScaleDownHook is triggered when a scaledown is to be performed.
 	// It's ensured that the hook will be triggered at least once, but it
 	// may trigger multiple times e.g. if the scaledown fails at a later
@@ -127,6 +132,11 @@ func (o *Operator) operate(ctx context.Context, sr StatefulResource) error {
 		return fmt.Errorf("failed to reconcile StatefulSet: %v", err)
 	}
 
+	err = sr.UpdateStatus(sts)
+	if err != nil {
+		return fmt.Errorf("failed to update status: %v", err)
+	}
+
 	err = o.operateNextPod(ctx, sts, sr)
 	return err
 }
diff --git a/operator/operator_test.go b/operator/operator_test.go
index de58bce..1a51db6 100644
--- a/operator/operator_test.go
+++ b/operator/operator_test.go
@@ -45,6 +45,7 @@ func (r *mockResource) VolumeClaimTemplates() []v1.PersistentVolumeClaim {
 }
 func (r *mockResource) Self() runtime.Object                           { return r.eds }
 func (r *mockResource) EnsureResources() error                         { return nil }
+func (r *mockResource) UpdateStatus(sts *appsv1.StatefulSet) error     { return nil }
 func (r *mockResource) PreScaleDownHook(ctx context.Context) error     { return nil }
 func (r *mockResource) OnStableReplicasHook(ctx context.Context) error { return nil }
 func (r *mockResource) Drain(ctx context.Context, pod *v1.Pod) error   { return nil }
diff --git a/pkg/apis/zalando.org/v1/types.go b/pkg/apis/zalando.org/v1/types.go
index 32af039..d203cfd 100644
--- a/pkg/apis/zalando.org/v1/types.go
+++ b/pkg/apis/zalando.org/v1/types.go
@@ -73,6 +73,8 @@ type ElasticsearchDataSetStatus struct {
 	// generation, which is updated on mutation by the API Server.
 	// +optional
 	ObservedGeneration *int64 `json:"observedGeneration,omitempty" protobuf:"varint,1,opt,name=observedGeneration"`
+	// Replicas is the number of Pods by the underlying StatefulSet.
+	Replicas int32 `json:"replicas" protobuf:"varint,2,opt,name=replicas"`
 
 	LastScaleUpStarted   *metav1.Time `json:"lastScaleUpStarted,omitempty"`
 	LastScaleUpEnded     *metav1.Time `json:"lastScaleUpEnded,omitempty"`