kubernetes - 保持kubernetes pod运行，直到最后一个用户断开连接

Question

我在kubernetes上运行了一个node.js容器，该容器处理websocket连接，这些连接通常保持打开状态，直到用户退出为止。现在，当我进行滚动更新或按比例缩小部署时，是否有办法阻止Pod被杀死，直到最后一个用户断开连接为止？

Answer 1

目前，Kubernetes不支持优雅的连接关闭。
terminationGracePeriodSeconds仅在Pod终止之前定义计时器。它不会处理Pod连接。

处理滚动更新的唯一方法是调整您的应用程序，使其能够透明地将客户端切换到其他Pod。

您可能还想看看Disruption Budget。在某些情况下，进行更可靠的设置可能会有所帮助。

A PDB specifies the number of replicas that an application can tolerate having, relative to how many it is intended to have. For example, a Deployment which has a .spec.replicas: 5 is supposed to have 5 pods at any given time. If its PDB allows for there to be 4 at a time, then the Eviction API will allow voluntary disruption of one, but not two pods, at a time.

PDBs cannot prevent involuntary disruptions from occurring, but they do count against the budget.

Pods which are deleted or unavailable due to a rolling upgrade to an application do count against the disruption budget, but controllers (like deployment and stateful-set) are not limited by PDBs when doing rolling upgrades – the handling of failures during application updates is configured in the controller spec. (Learn about updating a deployment.)

When a pod is evicted using the eviction API, it is gracefully terminated (see terminationGracePeriodSeconds in PodSpec.)