In general, the bottom layer is a small Linux distro (Ubuntu, Debian, Alpine), just enough to get you going. Ideally you choose a base image that is getting se

In general, the bottom layer is a small Linux distro (Ubuntu, Debian, Alpine), just enough to get you going. Ideally you choose a base image that is getting security updates on regular basis, and that doesn't have significant changes over time for the same tag. So e.g. `fedora` is bad base image, because one day you'll jump from Fedora 30 to Fedora 31. Likewise `ubuntu` isn't great. But `ubuntu:18.04` is the Long-Term Support release and so it'll be fairly stable. In the context of Python packaging I've written a more detailed guide to choosing a base image: https://pythonspeed.com/articles/base-image-python-docker-images/ https://pythonspeed.com/articles/base-image-python-docker-im...