A small note that you need gpg installed for this to work. If you have homebrew installed, this is as simple as:

$ brew update && brew install gpg

and there is a typo in the commands. The following command should read:

$ sudo ./coreos-xhyve-run

It had an extra sudo in the line originally.

Also, a space added to this command:

$ docker -H <ip-of-virtual-machine>:2375 run -it --rm busybox

between the -H and the IP/port.