You can almost always go back to mainframe for inspiration - back in the day they pretty much solved every problem you can think of. It has just taken 40-60 years to be able to do the same thing on consumer class hardware.
Last I checked there was still no mechanism where I could bill back resource usage in a multi-tenant kubernetes cluster so I think there is still work to do.
> bill back resource usage in a multi-tenant kubernetes cluster
I feel a bit dumb for asking, but what about process accounting? I'm not sure if it can deal with RAM and I/O, but it's better than nothing. (https://linux.die.net/man/8/sa)
Last I checked there was still no mechanism where I could bill back resource usage in a multi-tenant kubernetes cluster so I think there is still work to do.