Currently most docker images at https://registry.hub.docker.com/ are ubuntu based. I would like however to run a somewhat leaner base image, i.e. CoreOS. Und than build custom packages/images on top of it, i.e. erlang and yaws. Is there some easy or standart way to do this? Using the cros_sdk I could modify an image, but I'm not sure if I could just build few additional gentoo packages and package them as a parent image.
I guess I could somehow put the upstream portage tree into the CoreOS dev env/chroot, emerge the packages I need and import the binary packages into a new parent image. Are there instructions of how this could be done?