5.6 深入理解 StatefulSet (一): 拓扑状态

StatefulSet 将应用状态抽象成两种情况:

• 拓扑状态
  • 启动顺序
  • 网络标识
• 存储状态
  • 绑定同一数据

Service 原理:

• 请求 -> VIP -> Pod IP
• 请求 -> Service DNS
  • Normal Service: Service DNS -> VIP -> Pod IP
  • Headless Service: Service DNS -> Pod IP

定义 Headless Service:

• clusterIP: Node
• <pod-name>.<svc-name>.<namespace>.svc.cluster.local

apiVersion: v1
kind: Service
metadata:
    name: nginx
  labels:
      app: nginx
spec:
    ports:
      - port: 80
        name: web
  clusterIP: None
  selector:
      app: nginx

StatefulSet yaml 示例:

• serviceName

StatefulSet 通过 Headless 来保留网络标识, 通过编号来保留启动顺序.