Nice first pass! I haven't looked at the final image size, but I suspect that starting with ubuntu:latest means that you'll have a pretty large resulting image

Nice first pass! I haven't looked at the final image size, but I suspect that starting with ubuntu:latest means that you'll have a pretty large resulting image with a bunch of unnecessary software installed. For your next attempt, you might want to look into creating a more slim image that contains only the required dependencies. I guess an alternate version of this would be one which has the core Phoenix dependencies but none of the asset management / Node.js stuff. I have a Phoenix API w/ no assets that could use such an image :)