Images for a new domain

A Crucible run uses two pods. A domain that needs a toolchain must install it in both:

The runtime image does not depend on a domain. It contains gcc, openssl-devel, python3, git, and jq, and no other measurement tools. The sandbox contains the agent CLI and Python. The domain image must add all other tools that measure_cmd or the agent turn needs. examples/selfhost (Rust) is the example: docker/Containerfile.runtime-rust and docker/Containerfile.sandbox-rust.

What the two images must satisfy

Loop pod (Containerfile.runtime-<domain>)

• Use FROM ghcr.io/neuralmagic/crucible:<tag>. Keep WORKDIR /opt/crucible. Do not replace /usr/local/bin/{crucible,openshell,openshell-gateway}.
• Install the toolchain in a world-readable location (/usr/local/...), not under /root. On OpenShift, the pod runs as an arbitrary uid.
• Pre-fetch the dependencies that measure_cmd builds against. The loop pod has egress (crates.io answered 200 from crucible-system on waldorf on 2026-08-25), but a cold dependency fetch in the first measure is slow and often fails first.
• dnf is available (full UBI10).

Agent sandbox (Containerfile.sandbox-<domain>)

• Use FROM quay.io/aipcc/agentic-ci/claude-sandbox:<tag>. It is a minimal UBI10: it has rpm but no dnf and no compiler. The uid is sandbox (998), HOME=/sandbox, and claude is at /usr/local/bin/claude.

• To add RPMs, install them into a rootfs in a full UBI10 stage of the same release, and copy that rootfs over the image:

  FROM registry.access.redhat.com/ubi10/ubi:10.2 AS pkgs
  RUN dnf install -y --nodocs --installroot /mnt/rootfs --releasever 10 \
          --setopt install_weak_deps=false gcc glibc-devel binutils ... \
      && dnf clean all --installroot /mnt/rootfs
  FROM quay.io/aipcc/agentic-ci/claude-sandbox:0.3.11
  COPY --from=pkgs /mnt/rootfs/ /
  

  perf is not in the UBI repositories. Sampling profilers with their own sampler (samply) work. cargo flamegraph does not work.

• Install the toolchain under /usr/local, run chmod -R a+rwX on its caches, and put USER sandbox at the end. If you set ENV PATH, include the bin directory of the toolchain. The agent inherits it.

• Pre-fetch more dependencies here than in the loop pod. The sandbox has deny-by-default egress. A cargo add or pip install by the agent during a turn works only if the registry is on the [agent.openshell].endpoints allowlist of the manifest and the binary that fetches is in [agent.openshell].binaries (for example, /usr/local/cargo/bin/cargo). Files that are already in the image cache need neither.

Build

Both images are amd64 and large (compiler and dependency fetch). Build them on the cluster, not under QEMU:

buildit build quay.io/<you>/crucible-sandbox-<domain>:v1 -n weaton-dev \
    --kubecontext coreweave-waldorf --mode job -f Containerfile.sandbox-<domain> \
    --request cpu=8 --request memory=16Gi
buildit wait <job> -n weaton-dev --kubecontext coreweave-waldorf   # last line: digest-pinned ref

.dockerignore keeps target/, .claude/, and the example workspaces out of the build context. Pin CRUCIBLE_TAG for the runtime image (--build-arg CRUCIBLE_TAG=<tag>). If you do not, the engine version in the loop pod can be different from the controller version.

A new quay repository is private. The namespace needs an imagePullSecrets entry (a kubernetes.io/dockerconfigjson secret from ~/.docker/config.json) before the pod can pull the image. Without it, the pod stays in ImagePullBackOff with a 401.

Verify the images

Before a manifest uses an image, run the image as an unexpected uid. Check the toolchain, the cache, and an offline build:

kubectl run smoke --restart=Never --image=<ref> \
    --overrides='{"spec":{"imagePullSecrets":[{"name":"quay-pull"}],"securityContext":{"runAsUser":12345,"runAsGroup":0}}}' \
    --command -- sh -c 'id; cargo --version; cd /tmp && cargo new -q t && cd t && cargo build -q --offline && ./target/debug/t'

Then run crucible check --manifest <pack>/crucible.toml locally. It runs measure_cmd and the gate self-test. Set backend = "openshell" and sandbox_image, and deploy.