On a mac system, I start the register following the deploy document:
docker run -d -p 5000:5000 --restart=always --name registry registry:2
If you are using docker-machine, see "Port forwarding in docker-machine?"
either port forward the 5000 port on the VirtualBox level (meaning localhost:5000 will work)
localhost:5000
VBoxManage controlvm "boot2docker-vm" natpf1 "tcp-port5000,tcp,,5000,,5000";
or use the ip returned by $(docker-machine ip )
$(docker-machine ip )