apiVersion: v1
kind: Service
metadata:
  name: mysql-slave-external-service
  namespace: default
spec:
  type: NodePort # NodePort 或 LoadBalancer（根据环境选择）
  selector:
    app: mysql
    role: slave
  ports:
    - protocol: TCP
      port: 3306
      targetPort: 3306
      nodePort: 30307 # 可选，指定 NodePort(30000 - 32767)