RFC: remove devmapper driver

[kolyshkin]

It seems that no one is using devicemapper storage driver nowadays, since overlayfs is so much better.

Can it be deprecated and removed? I see that moby/moby did that recently.

[rhatdan]

Makes sense to me.
@nalind @rhvgoyal @vrothberg @giuseppe @mtrmac @saschagrunert WDYT?

[giuseppe]

yes, I agree, let's drop old unmaintained stuff

[saschagrunert]

I agree we should remove it if nobody maintains it any more.

@alicefr are you aware of anyone using devicemapper? I'm not sure if we discussed something like this in the past.

[alicefr]

@saschagrunert not that I'm aware. AFAIU, kata is relying on virtiofs, hence a filesystem storage driver will be enough. I still believe that for confidential computing use cases, we will need some block-based storage drivers, but probably not devicemapper.

[vrothberg]

SGTM 👍