overthinkos/ubuntu

ubuntu

Base Ubuntu 24.04 (noble) image. Distinguished from /charly-distros:debian by adopt mode: the upstream ubuntu:24.04 base image ships a pre-existing ubuntu:ubuntu account at uid 1000, and the embedded distro.ubuntu vocabulary declares base_user: so the charly generator honors that account rather than creating a new one.

The Ubuntu family lives in its own overthinkos/ubuntu repo (git submodule at box/ubuntu) — a SEPARATE repo from overthinkos/debian (Debian and Ubuntu each have their own repo). The ubuntu base is owned there and composes the main repo's candies by git reference plus the embedded build vocabulary. Because distro.ubuntu is inherits: debian, the embedded build vocabulary (which carries BOTH distro configs) resolves the inheritance — overthinkos/ubuntu needs no reference to overthinkos/debian. Build from the submodule: charly -C box/ubuntu box build ubuntu (or charly --repo overthinkos/ubuntu box build ubuntu). Nothing in main consumes any Ubuntu box, so there is no main ↔ ubuntu coupling.

Box Properties

| Property | Value | |----------|-------| | Base | ubuntu:24.04 | | Pkg | deb | | Distro tags | ["ubuntu:24.04", "ubuntu"] (symmetric with a target: vm deploy's distroTagChain; NO debian fallback — every deb-family layer carries an explicit ubuntu section, and the cascade would otherwise UNION debian-only packages onto ubuntu) | | Layers | (none — base image only) | | Platforms | linux/amd64 | | User | ubuntu / uid 1000 (adopt mode) | | Home | /home/ubuntu | | Registry | ghcr.io/overthinkos |

User model — adopt from base image

The embedded distro.ubuntu vocabulary inherits from distro.debian (same apt bootstrap template) and adds a base_user: block:

distro:
  ubuntu:
    inherits: debian
    base_user:
      name: ubuntu
      uid: 1000
      gid: 1000
      home: /home/ubuntu

Any downstream image with user_policy: auto (the default) that did not explicitly set its own user: field will adopt this — resolved.User = "ubuntu", resolved.Home = "/home/ubuntu", resolved.UserAdopted = true. The bootstrap emits no useradd; it emits a one-line comment documenting the adoption:

# User ubuntu (uid=1000) adopted from base image (declared in charly/charly.yml distro.base_user) — no useradd needed
WORKDIR /home/ubuntu
USER 1000

This architecture is declarative (what the base image ships) + policy-driven (how to reconcile with the image's configured user). Three policy values:

| Policy | Behavior on this base | |--------|----------------------| | auto (default) | Adopt ubuntu:ubuntu — image inherits the upstream account. | | adopt | Same as auto here; hard-errors on bases without base_user:. | | create | Override — force-create a different uid-1000 account (fails if useradd collides). |

See /charly-image:image "user_policy" and /charly-build:build "base_user" for the full table covering all four distros.

Why adopt over rename?

Adopt mode honors the existing ubuntu account rather than renaming it to user via usermod -l, because:

1. Ubuntu's cloud-init tooling, docs, and /etc/passwd metadata assume the account is named ubuntu.
2. Renaming is an invisible base-image mutation — breaks in hard-to-debug ways.
3. The rename approach doesn't scale to Debian cloud images (or future distros) that ship their own pre-existing uid-1000 accounts with different names.

Adopt mode respects the base image's contract and scales declaratively. See /charly-coder:sshd for the getent passwd 1000 pattern that makes candy content (sudoers in particular) work uniformly across both create and adopt modes.

Bootstrap

FROM ubuntu:24.04
RUN --mount=type=cache,dst=/var/cache/apt,sharing=locked
    --mount=type=cache,dst=/var/lib/apt,sharing=locked
    apt-get update && apt-get install -y --no-install-recommends curl ca-certificates gnupg && \
    ... install go-task binary ...
# User ubuntu (uid=1000) adopted from base image (declared in charly/charly.yml distro.base_user) — no useradd needed
WORKDIR /home/ubuntu
USER 1000

Dockerhub rate-limit caveat

The upstream ubuntu:24.04 pull from Dockerhub is unauthenticated-rate-limited (100 pulls / 6h / IP). If charly box build ubuntu fails with toomanyrequests, pull from AWS ECR Public and retag:

podman pull public.ecr.aws/docker/library/ubuntu:24.04
podman tag public.ecr.aws/docker/library/ubuntu:24.04 docker.io/library/ubuntu:24.04
charly box build ubuntu

ECR Public mirrors the Dockerhub library namespace without rate-limiting.

Downstream / sibling entries (all in overthinkos/ubuntu)

• /charly-distros:ubuntu-builder — pixi/npm/cargo multi-stage builder.
• /charly-coder:ubuntu-coder — kitchen-sink dev box.
• /charly-distros:ubuntu-debootstrap-builder — privileged debootstrap builder (base: debian:13).
• /charly-distros:ubuntu-debootstrap — bootstrap-from-scratch rootfs.
• /charly-vm:ubuntu — the ubuntu-debootstrap bootstrap VM + check-ubuntu-debootstrap-vm bed.

Verification

charly -C box/ubuntu box build ubuntu
charly shell ubuntu                       # drops into /home/ubuntu as uid 1000
id                                    # uid=1000(ubuntu) gid=1000(ubuntu)
charly -C box/ubuntu box validate     # the embedded build vocabulary resolves distro.ubuntu (inherits debian)

Related boxes

• /charly-distros:debian — sibling deb-family base without adopt mode (Debian 13 ships no pre-existing uid-1000 user).
• /charly-distros:ubuntu-builder — multi-stage builder.
• /charly-coder:ubuntu-coder — kitchen-sink dev box.
• /charly-distros:fedora — RPM-family counterpart.
• /charly-distros:arch — pacman-family counterpart.

Related commands

• /charly-build:build — base_user: declaration format, which lives in the embedded distro.ubuntu vocabulary.
• /charly-image:image — user_policy: field + reconciliation.
• /charly-build:generate — adopt-vs-create writeBootstrap emission.

Related candies (cross-distro patterns this base enables)

• /charly-coder:sshd — getent passwd 1000-based sudoers works for both user (create) and ubuntu (adopt).
• /charly-coder:language-runtimes — Microsoft dotnet-install.sh (Ubuntu noble doesn't ship dotnet-sdk-9.0 in main; Microsoft's noble apt repo only has 10.0; the dotnet-install.sh --channel 9.0 is the cross-distro solution).

When to use this skill

MUST be invoked when:

• Building or troubleshooting the ubuntu base image.
• Adding any Ubuntu-based box (it will inherit the adopt-mode ubuntu:ubuntu identity by default).
• Debugging ${USER} / ${HOME} differences between Ubuntu and other deb-based boxes (ubuntu-coder → ubuntu:/home/ubuntu; debian-coder → user:/home/user).
• Understanding why ubuntu-coder's /etc/sudoers.d/charly-user says ubuntu ALL=(ALL) NOPASSWD: ALL rather than user.