Some of the discussions in #831 brought this out:

I need reboot save volumes used to store mysql databases or webspace content. So lifetime needed is forever (not dependent on service / pod / host uptime). Changes should be saved directly.

Most docker containers today run as root, so you should be able to write to
a hostPath mount. If you are running your containers as non-root (good for
you!) I would be amenable to some different tweak on the model that gave
you what you wanted. For example, something like

"hostPath": { "path": "/tmp/mypod", "uid": 93, "gid": 76, "mode": 0700 }

...with well-defined semantics (e.g. only applies if the path does not
exist or already exists in the exact same config). or even something
higher level to abstract the real host path away.