Docker images for GitLab Kubernetes Agent

What are the requirements for Docker images that we run as part of GitLab Chart? Is it documented somewhere? I know they are built in https://gitlab.com/gitlab-org/build/CNG but this repository just contains Docker files so it's not clear what is expected/needed, the requirements.

GitLab Kubernetes Agent consists of two programs, two docker images. One runs "next to GitLab" (Kubernetes Agent Server - kas) and another one (Kubernetes Agent - agentk) - in a Kubernetes cluster. I can imagine that at least agentk may need to be not only x86_64, but maybe ARM too in the future.

Currently both images use the following images as base:

• gcr.io/distroless/static for normal builds
• gcr.io/distroless/cc for builds with race detector enabled (to satisfy dependency on libstdc++.so.6, see https://github.com/golang/go/issues/14481).

Both of the base images are based on packages from Debian 9 (stretch).

The resulting images are 9-40 MiB in size, which is very nice.

We've discussed this a bit on Slack, but I'd like to have a conversation that is visible, so that anyone can contribute, and is recorded properly in an issue.

@ggillies @twk3 @WarheadsSE