k8s中设置弹性副本缩容的策略

Question

k8s中设置了弹性副本，达到缩容的条件后，删除副本时，是根据副本创建的时间倒序删除，还是随机删除啊，有什么机制吗

Answer 1

Controller 中有相关的机制，源代码请查阅： https://github.com/kubernetes/kubernetes/blob/c9c6901303cd83fc0941c2c9964771404bf9cf9f/pkg/controller/controller_utils.go#L731

这里复述一下源代码中描述的优先删除哪些pod：

1. Unassigned < assigned
2. PodPending < PodUnknown < PodRunning
3. Not ready < ready
4. Been ready for empty time < less time < more time
5. Pods with containers with higher restart counts < lower restart counts
6. Empty creation time pods < newer pods < older pods

简而言之，未分配、未运行的优先删除，运行时间短、重启次数多的优先删除。