This involves the registry, docker pull/run/create option for disabling content trust verification.
More info here:
overview - http://blog.docker.com/2015/08/content-trust-docker-1-8/?mkt_tok=3RkMMJWWfF9wsRonuqTMZKXonjHpfsX57e0rXaW0lMI%2F0ER3fOvrPUfGjI4ATsZnI%2BSLDwEYGJlv6SgFQ7LMMaZq1rgMXBk%3D
tutorial - https://gist.github.com/diogomonica/7445950971b2d3a7c13f