head-less请求的例子如下：

apiVersion: apps/v1
kind: StatefulSet
metadata:
  labels:
    app: swm
  name: swm
spec:
  replicas: 2
  selector:
    matchLabels:
      app: swm
  serviceName: swm-headless
  template:
    metadata:
      labels:
        app: swm
      name: swm
    spec:
      containers:
      - env:
        image: gpdb-6
        imagePullPolicy: IfNotPresent
        name: postgresql
        ports:
        - name: ssh
          containerPort: 22
        - name: pg
          containerPort: 5432
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: swm
  name: swm
spec:
  ports:
  - name: ssh
    port: 22
    protocol: TCP
    targetPort: 22
  - name: pg
    port: 5432
    protocol: TCP
    targetPort: 5432
  selector:
    app: swm
  type: ClusterIP
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: swm
  name: swm-headless
spec:
  clusterIP: None
  ports:
  - name: ssh
    port: 22
    protocol: TCP
    targetPort: 22
  - name: pg
    port: 5432
    protocol: TCP
    targetPort: 5432
  selector:
    app: swm
  type: ClusterIP
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: swm
  name: swm-svc
spec:
  ports:
  - containerPort: 5432
    hostPort: 5432
    name: pg
    protocol: TCP
  - containerPort: 22
    hostPort: 22
    name: ssh
    protocol: TCP
  selector:
    app: swm
  sessionAffinity: None
  type: ClusterIP

启用head-less服务之后，同一个服务的不同pod之间就可以通过head-less方式查询到对方