sbates130272/batesste-ci-images-ubuntu-base repository overview

⁠ubuntu-base

Shared Ubuntu foundation for every image in this collection.

⁠Overview

Every other batesste-ci-images image is built FROM this one. It exists so the things they all need are installed, configured and cached exactly once:

• a C/C++ toolchain and the build tools shared across the collection (build-essential, cmake, ninja-build, ccache, pkg-config)
• git, curl and wget, tuned for large clones and downloads through a corporate proxy
• CA certificates, including AMD's root CA when the build context provides it
• unattended-upgrades removed and the periodic apt timers disabled, so an automatic update can never take the apt lock mid-build

The bar for adding to this image is deliberately high: everything here is paid for by all ten downstream images, so it holds only what at least three of them already installed.

⁠Base image

• ubuntu:24.04

The FROM line is a literal rather than an ARG. ci-images-tool.py parses it to derive the Ubuntu version in the tag, and turning it into a build arg would change the first instruction of the image and invalidate every layer below it on every build.

⁠apt caching

This image hands .deb retention to BuildKit cache mounts: it deletes /etc/apt/apt.conf.d/docker-clean and sets Keep-Downloaded-Packages "true".

That has a consequence for anything built on top. Every apt step in a downstream image must mount both cache directories, or the downloaded packages land in the image layer instead of the cache:

RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
    --mount=type=cache,target=/var/lib/apt/lists,sharing=locked \
    apt-get update && apt-get install -y --no-install-recommends ...

⁠Usage

Rarely run directly -- it is a base layer -- but it is a usable Ubuntu shell with a working toolchain:

docker run --rm -it \
  docker.io/sbates130272/batesste-ci-images-ubuntu-base:latest

To layer on it, take the published tag as a build arg:

ARG BASE_IMAGE=docker.io/sbates130272/batesste-ci-images-ubuntu-base:latest
FROM ${BASE_IMAGE}

ci-images-tool.py fills BASE_IMAGE in automatically for any image that declares base: ubuntu-base in images.yml⁠.

⁠Tags

The tag variant for this image is the Ubuntu release it was built from, for example ubuntu24.04. See the repository README⁠ for the full tag scheme.