Setting the TTL for discarding task pods on Kubernetes.

I'm experimenting with running Flink 1.10.0 on native Kubernetes (version 1.17).

After a job ends the task pods that were used to run it are discarded quite quickly.

I found that if my job goes wrong I have too little time to look at all of the logs.

I propose having a new config setting that allows me to run Flink on k8s where I can set the minimum time before an idle task pod is discarded.

That way I can start Flink with a pod ttl of an hour (or something like that) so I have enough time to go through the logs and figure out what I did wrong.