apiVersion: v1
kind: Service
metadata:
  name: stateful-svc
spec:
  selector:
    app: stateful
  clusterIP: None
  ports:
    - port: 8080
      targetPort: 80

---

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: statefulset
spec: # 这部分字段类似 Deployment
  replicas: 2
  serviceName: stateful-svc # 匹配上面的 metadata.name
  updateStrategy:
    type: RollingUpdate # 默认是RollingUpdate，还支持 OnDelete
    rollingUpdate:
      partition: 0
  selector:
    matchLabels:
      app: stateful
  template:
    metadata:
      labels:
        app: stateful
    spec:
      containers:
        - name: python-svc-stateful
          image: python:3.7
          command: [ 'sh', '-c' ]
          # 先写一句包含Pod主机名的文字到 /dir/data，同样方式生成 index.html，再使用这个index.html在80端口启动一个web服务器
          args: [ 'echo "This host is $(hostname)"! >> /dir/data; echo "<p> The host is $(hostname)</p>" > index.html; python -m http.server 80' ]
          volumeMounts:
            - mountPath: /dir
              name: stateful-data
          ports:
            - containerPort: 80
  volumeClaimTemplates: # StatefulSet特有字段，配置每个Pod的卷需求（Pod创建时将自动创建一个名称包含pod序号的PVC，若已存在同名PVC则不会重复创建）
    - metadata:
        name: stateful-data
      spec:
        accessModes: [ "ReadWriteMany" ]
        storageClassName: sc-hostpath # 匹配下面的 StorageClass
        resources:
          requests:
            storage: 200Mi

---

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: sc-hostpath
provisioner: kubernetes.io/no-provisioner # 使用hostpath作为存储后端
volumeBindingMode: WaitForFirstConsumer

---

# 因为示例使用 hostpath，所以才手动创建PV。由于要启动两个Pod，所以还需要创建两个PV给两个Pod使用。

# PV0 给 pod0用

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-hostpath-0
spec:
  capacity:
    storage: 500Gi # 创建时并不会验证实际有这么多空间
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain # 手动创建本地卷时，仅支持Retain
  storageClassName: sc-hostpath # 匹配上面的metadata.name
  local:
    path: /home/host-sts-pv-dir # 必须在节点手动创建
  nodeAffinity: # 创建本地卷的必须字段，k8s会在匹配下面条件的节点上创建PV，如果没有匹配的节点，则引用的Pod和PV都会一直pending（通过describe可以查看原因）
    required:
      nodeSelectorTerms:
        - matchExpressions:
            - key: kubernetes.io/hostname
              operator: In
              values:

                - k8s-node1
---

# PV1 给 pod1用

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-hostpath-1
spec:
  capacity:
    storage: 500Gi # 创建时并不会验证实际有这么多空间
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain # 手动创建本地卷时，仅支持Retain
  storageClassName: sc-hostpath # 匹配上面的metadata.name
  local:
    path: /home/host-sts-pv-dir # 必须在节点手动创建
  nodeAffinity: # 创建本地卷的必须字段，k8s会在匹配下面条件的节点上创建PV，如果没有匹配的节点，则引用的Pod和PV都会一直pending（通过describe可以查看原因）
    required:
      nodeSelectorTerms:
        - matchExpressions:
            - key: kubernetes.io/hostname
              operator: In
              values:
                - k8s-master