- Drop the module-level paragraph emphasizing the single-UID security
boundary (#issuecomment-5010): redundant given the safe environment.
- Move `podman` from each agent image (claude, codex, pi) into the
`build_image` derived layer so bottles without `nested_containers`
pay no image-size cost (#issuecomment-5013).
- Update `build_image` docstring and inline comments to reflect the move.
- Add TODO(#394) noting the planned docker-layer abstraction refactor.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
netavark shells out to `nft` for the bridge network every compose file
expects, and aardvark-dns serves name resolution inside nested
containers. Neither arrives with the base image's
`--no-install-recommends` podman, and each fails at a different and
misleading layer: without nft containers are created but never start;
without aardvark-dns DNS inside a container fails while the engine, the
pulls, and the bridge all look healthy. That last one is the likeliest
explanation for the "DNS inside nested containers fails entirely" note
in #392 — a missing package, not a design gap.
Verified on the macOS host: with passt alone, `docker run` reached
netavark and died on "unable to execute nft".
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
podman 5 uses pasta as the default rootless network helper; podman 4
used slirp4netns. The spike was written against bookworm's podman 4.3.1,
so its package list never included passt — and the trixie bump (#451)
changed the default out from under it. Every nested container failed to
start with "could not find pasta", while image pulls and the service
itself worked, which disguised a missing dependency as a compat-API bug.
The bootstrap now checks for pasta up front so this fails with a clear
message instead of surfacing at the first `docker run`.
Note the sun_path fix in a12d2191 did NOT cause or cure this; that path
was over the 108-byte limit independently and would have bitten as soon
as attach was reached.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
podman derives conmon's attach socket as
`$XDG_RUNTIME_DIR/libpod/tmp/socket/<64-hex-id>/attach`. With the
descriptive `/tmp/bot-bottle-podman-run` that path is 116 bytes, past
the 108-byte sun_path limit, so every attached `docker run` failed with
"unable to upgrade to tcp, received 500" — while image pulls and the
service itself worked, which is what made it look like a compat-API bug
rather than a path-length one.
Found on the macOS host: quay.io pulled fine and then no container
could be started. Test pins the budget so a more readable name cannot
silently reintroduce it.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Adds the `nested_containers` bottle flag. On the macOS backend it starts
a rootless podman service inside the bottle and exposes its
Docker-compatible API socket, so the agent still runs `docker` and
`docker compose`. No host daemon socket is mounted and the guest gains
no capabilities; backends that cannot run a guest-local engine reject
the flag in the shared prepare template rather than ignoring it.
Podman rather than rootless Docker because Apple Container's capability
bounding set omits CAP_SYS_ADMIN, which the kernel requires to write a
multi-range uid_map via newuidmap. With no subordinate UID range podman
falls back to a single-UID self-mapping an unprivileged process may
write itself, so the image build strips /etc/subuid and /etc/subgid
entries rather than adding them.
That mapping is also why nested containers are not an isolation layer:
root inside one is the agent user outside it. They are a build/test
convenience; the bottle remains the boundary.
Ports the spike branch onto main, renaming docker_access — it implied
Docker and granted access to nothing on the host — and drops podman
from the derived layer now that every built-in image ships it (#451).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
didericis-claude
didericis