### Summary The current base image is `FROM ubuntu:16.04` which is already a few years old. ### Proposal I propose to upgrade the base image to one of the following: #### `ubuntu:18.04` This is the most obvious variant, has upstream support and does not require that many changes. #### `debian:buster-slim` This base image (especially the `slim` variant) is slightly smaller that the current Ubuntu image (https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1712#note_20515578). Most other container in the Docker library are based on Debian. Since the layers can be cached and shared across different images, this could save additional resources on hosts where multiple containers are running in parallel.