I initially reported that against Docker 1.7.0 itself as moby/moby#14092 but apparently they just fixed their own client in 1.7.1. As docker-py fixed that themselfes (docker/docker-py@f8ad2da) the correct way actually seems to be to fix that in docker-java itself. I spoke to @vdemeester on IRC and he said that it is more or less expected behaviour.

(Ping @alexec just that you know that orchestration and maven-plugin currently broken for docker 1.7.x and private registries)