Docker image format

Question

I would like to build a Docker image without docker iself. I have looked at Packer, but it requiers to have Docker installed on the builder host.

I have looked at the Do

Answer 1

The Docker image format is specified here: https://github.com/docker/docker/blob/master/image/spec/v1.md

The simplest possible image is a tar file containing the following:

repositories
uniqid/VERSION
uniqid/json
uniqid/layer.tar

Where VERSION contains 1.0, layer.tar contains the chroot contents and json/repositories are JSON files as specified in the spec above.

The resulting tar can be loaded into docker via docker load < image.tar