You can try the following steps:
You can find which process is hogging file descriptors by running the following command:
lsof | awk '{print $2}' | sort | uniq -c | sort -n
You will get a sorted list of open FD counts with the pid of the process. Then you can look up each process w/
ps -p <pid>
If the main hogs are docker/kubernetes, then I would recommend following along on the issue th caesarxuchao reference.
I think it would be helpful for you.