kubernetes: PodTopologySpreadConstraints doesn't work

What happened: The kubernetes cluster have three worker nodes and a master one, their labels as follows:

[root@master-3 yaml]# kubectl get node -l'zone' --show-labels
NAME          STATUS   ROLES    AGE    VERSION   LABELS
master        Ready    worker   4d3h   v1.18.6   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=master,kubernetes.io/os=linux,node-role.kubernetes.io/worker=,zone=1
slave-3.146   Ready    worker   15d    v1.18.6   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=slave-3.146,kubernetes.io/os=linux,node-role.kubernetes.io/worker=,zone=2
zbw-0.211     Ready    worker   15d    v1.18.6   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=zbw-0.211,kubernetes.io/os=linux,node-role.kubernetes.io/worker=,role=proxy,zone=3
[root@master-3 yaml]#

When i tried to use statefulset to verify podSpreadConstraints, the result was not expected.

[root@master-3 yaml]# kubectl get pod -ntest -owide -l'foo=bar'
NAME      READY   STATUS    RESTARTS   AGE     IP               NODE        NOMINATED NODE   READINESS GATES
pause-0   1/1     Running   0          5m5s    172.31.126.231   zbw-0.211   <none>           <none>
pause-1   1/1     Running   0          4m54s   172.31.126.224   zbw-0.211   <none>           <none>
pause-2   1/1     Running   0          4m37s   172.31.126.246   zbw-0.211   <none>           <none>

What you expected to happen: What i expected is all pods would be distributed on different worker nodes, but all of them were on the same one. How to reproduce it (as minimally and precisely as possible): Here is my yaml file

apiVersion: v1
kind: Service
metadata:
  name: pause
  namespace: test
spec:
  clusterIP: None
  selector:
    foo: bar
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: pause
  namespace: test
  labels:
    foo: bar
spec:
  # podManagementPolicy: Parallel
  selector:
    matchLabels:
      foo: bar
  serviceName: pause
  replicas: 3
  template:
    metadata:
      name: pause
      labels:
        foo: bar
    spec:
      topologySpreadConstraints:
      - maxSkew: 1
        topologyKey: zone
        whenUnsatisfiable: DoNotSchedule
        labelSelector:
          matchLabels:
            foo: bar
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: zone
                operator: Exists
      containers:
      - name: pause
        image: lenhattan86/pause:3.1
        imagePullPolicy: Always

Anything else we need to know?: This issue 91152 is also seen. Here are some references advance-usage pod-topology-spread-constraints

Environment:

• Kubernetes version (use kubectl version): Client Version: version.Info{Major:“1”, Minor:“18”, GitVersion:“v1.18.6”, GitCommit:“e56f0e6297981b70192ae06db03f6c92301eb704”, GitTreeState:“clean”, BuildDate:“2020-07-17T05:36:26Z”, GoVersion:“go1.13.9”, Compiler:“gc”, Platform:“linux/amd64”} Server Version: version.Info{Major:“1”, Minor:“18”, GitVersion:“v1.18.6”, GitCommit:“dff82dc0de47299ab66c83c626e08b245ab19037”, GitTreeState:“clean”, BuildDate:“2020-07-15T16:51:04Z”, GoVersion:“go1.13.9”, Compiler:“gc”, Platform:“linux/amd64”}

• Cloud provider or hardware configuration:

• OS (e.g: cat /etc/os-release): NAME=“CentOS Linux” VERSION=“7 (Core)” ID=“centos” ID_LIKE=“rhel fedora” VERSION_ID=“7” PRETTY_NAME=“CentOS Linux 7 (Core)” ANSI_COLOR=“0;31” CPE_NAME=“cpe:/o:centos:centos:7” HOME_URL=“https://www.centos.org/” BUG_REPORT_URL=“https://bugs.centos.org/” CENTOS_MANTISBT_PROJECT=“CentOS-7” CENTOS_MANTISBT_PROJECT_VERSION=“7” REDHAT_SUPPORT_PRODUCT=“centos” REDHAT_SUPPORT_PRODUCT_VERSION=“7”

• Kernel (e.g. uname -a): Linux master-3.145 3.10.0-957.el7.x86_64 #1 SMP Thu Nov 8 23:39:32 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

• Install tools: kubeadm

• Network plugin and version (if this is a network-related bug):

• Others: