I am a big fan of these nano-images and really want to support them better in Docker's builder. See "nested builds" and "image squashing". Basically, you should

I am a big fan of these nano-images and really want to support them better in Docker's builder. See "nested builds" and "image squashing". Basically, you should be able to define a Dockerfile for the build environment, then within that define how to produce the final image. Then you need squashing to avoid carrying the build layers. I personally played with aboriginal Linux, but I believe it's the same idea :)