I’m having the same problems with our public images.
If you pull down the “enonic/java8” image it eats up 5gb of disk alone, while on docker 1.6.2 it uses 1GB
Both servers are identical setup with the same cloud init file and I’m using the official ubuntu 14.04.2 LTS cloud images on a set of openstack instances to run docker on.
Docker file: https://github.com/enonic/docker-xp/blob/master/docker-java8/Dockerfile