If your container has mapped its port on the VM 12008 port, you would need to make sure you have port forwarded 12008 in your VirtualBox connection settings, as I mention in “How to connect mysql workbench to running mysql inside docker?“
VBoxManage controlvm "boot2docker-vm" --natpf1 "tcp-port12008 ,tcp,,12008,,12008"
VBoxManage controlvm "boot2docker-vm" --natpf1 "udp-port12008 ,udp,,12008,,12008"