Boot2Docker
Linux distribution made specifically to run Docker containers
... leverages VirtualBox's VBoxManage to initialise, start, stop and delete the VM right from the command line. Docker Machine auto logs in using the generated SSH key, but if you want to SSH into the machine manually (or you're not using a Docker Machine managed VM), you can do so. Boot2docker uses Tiny Core Linux, which runs from RAM and so does not persist filesystem changes by default.