应用高可用

应用高可用的一般原则
应用遵循 The Twelve-Factor App​
使用 Service 和多副本 Pod 部署应用
多副本通过反亲和性避免单节点故障导致应用异常
使用 PodDisruptionBudget 避免驱逐导致的应用不可用
使用 preStopHook 和健康检查探针保证服务平滑更新
优雅关闭
为 Pod 配置 terminationGracePeriodSeconds，并通过 preStop 钩子延迟关闭容器应用以避免 kubectl drain 等事件发生时导致的应用中断：
restartPolicy: Always
terminationGracePeriodSeconds: 30
containers:
- image: nginx
  lifecycle:
    preStop:
      exec:
        command: [
          "sh", "-c",
          # Introduce a delay to the shutdown sequence to wait for the
          # pod eviction event to propagate. Then, gracefully shutdown
          # nginx.
          "sleep 5 && /usr/sbin/nginx -s quit",
        ]
详细的原理可以参考下面这个系列文章
​1. Zero Downtime Server Updates For Your Kubernetes Cluster​
​2. Gracefully Shutting Down Pods in a Kubernetes Cluster​
​3. Delaying Shutdown to Wait for Pod Deletion Propagation​
​4. Avoiding Outages in your Kubernetes Cluster using PodDisruptionBudgets​
参考文档
​Kubernetes Pod Lifecycle​
​Kubernetes PodDisruptionBudget​

最近更新 9mo ago