boot2docker is not connected to Vagrant, it speaks directly with Virtualbox. Maybe watch out in the boot2docker github repo when they gonna update it https://github.com/boot2docker/boot2docker/issues/979 My advice also: Avoid the official docker installation. It will downgrade your Virtualbox 5.0 pretty sure!

therealmarv mentioned 1.7.3 (coming in the next few days): https://github.com/mitchellh/vagrant/issues/5572