Kubernetes scale down specific pods

You can annotation specific pod with controller.kubernetes.io/pod-deletion-cost: -999 and enable PodDeletionCost featuregate. This feature is implement alpha in 1.21 and beta in 1.22.

controller.kubernetes.io/pod-deletion-cost annotation can be set to offer a hint on the cost of deleting a pod compared to other pods belonging to the same ReplicaSet. Pods with lower deletion cost are deleted first.

https://github.com/kubernetes/kubernetes/pull/99163 https://github.com/kubernetes/kubernetes/pull/101080

This isn't currently possible. When you scale down the number of replicas, the system will choose one to remove; there isn't a way to "hint" at which one you'd like it to remove.

One thing you can do is you can change the labels on running pods which can affect their membership in the replication controller. This can be used to quarantine pods that you want to debug (so that they won't be part of a service or removed by a scaling event) but might also be possible to use for your use case.