[davexunit]

>The absolute star feature of docker is being able to mount a file from the host to the container.

This is a simple bind-mount and isn't special at all.

    mount("/foo", "/container/foo", "none", MS_BIND);

Also, virtual machines have had things like 9p that allow the same thing.

[alextgordon]

I don't think there is enough RAM in my laptop to run five VMs simultaneously :)

[davexunit]

Yeah, containers are much slimmer.