Availability/Reproducibility of Ubuntu Minimal as Docker image

Question

While for Debian you find on Docker Hub "slim" distributions, it seems not the case with Ubuntu.

Now there is a "minimal Ubuntu for public clouds" distro from Canonical, but I can find just cloud VM images; is there a Dockerfile for that, as well?

Answer 1

The answer to the question "is there a Dockerfile for that, as well?"

https://github.com/tianon/docker-brew-ubuntu-core/tree/dist-amd64

Note their git branches contain the actual release build based on architecture.

Answer 2

Most Dockerfiles start from a parent image. If you need to completely control the contents of your image, you might need to create a base image instead. A base image either has no FROM line in its Dockerfile, or has FROM scratch.

Create a full image using tar

In general, start with a working machine that is running the distribution you’d like to package as a parent image, though that is not required for some tools like Debian’s Debootstrap, which you can also use to build Ubuntu images.

There are more example scripts for creating parent images in the Docker GitHub Repo:

BusyBox
CentOS / Scientific Linux CERN (SLC) on Debian/Ubuntu or on CentOS/RHEL/SLC/etc.
Debian / Ubuntu

Create a base image

I guess after creating you can export this on docker hub with Dockerfile.

Answer 3

You can walk backward in DockerFile. You can uninstall/cleanup "groups" "packages" to slim down. You can create your custom minimal image from that cloud image.It is like just a snapshot of a specific image at some point.

This is the minimal position. This is when the baby is born.

docker pull hello-world

Dockerfile-linux.template

You may want to look at kickstart/preseed if you want deep-diving.It is about being an official image or some image on which you have full control. ]2