Kubernetes statefulset podAntiAffinity

bellow works fine, k8s runs one pod each node, but issue when one of nodes fails, k8s creates 2 pods in a node. Is it possible only one pod in a node?

apiVersion: apps/v1
kind: StatefulSet
metadata:
name: testpod
spec:
replicas: 3
selector:
matchLabels:
app: testpod
serviceName: “srv”
template:
metadata:
labels:
app: testpod
spec:
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: “app”
operator: In
values:
- testpod
topologyKey: “kubernetes.io/hostname
containers: