Say I use a Dockerfile to build an image from ubuntu:14.04, then install some things, add some code, then push to a repo where the image will be deployed for testing and eventually production.
My image works out to be > 2gbs. Most of that is the underlying and unchanging ubuntu:14.04 image layer.
Instead of shipping around my bloated image containing the ubuntu:14.04 base layer - theoretically i should be able to ensure my target systems already have this image - and i'd ship around just my higher level changes which would be applied on top.
(of course if the underlying image changed, i'd have to ensure the latest version was available on the target systems also)
Can we do this?
There is a tool called 'bub' which can split images into chunks and recognize only the differences. Check it out