Stage 2 of the docker-free Firecracker backend (#348): stop building the
fixed infra image on the launch host. The infra VM's rootfs is host- and
bottle-agnostic (authorized_keys + guest IP ride the kernel cmdline, not the
rootfs), so it's built once off-host and published as a versioned, ready-to-
boot ext4; the launch host downloads + verifies + boots it — no Docker, no
image tooling, just HTTP + gunzip.
- infra_artifact.py: version = content hash of the rootfs inputs (the shipped
bot_bottle package + the three Dockerfiles + the init), so a launch host
pulls the artifact matching its code and a content change can't silently
boot a stale rootfs. Pull + sha256-verify (fail-closed) + gunzip from a
Gitea generic package; base/owner/token configurable, default this Gitea.
- infra_vm.ensure_built/boot default to the pull path; BOT_BOTTLE_INFRA_BUILD=
local keeps the docker build-from-source path for iterating on Dockerfiles.
- publish_infra.py: the off-host half — builds the images with Docker, mke2fs
the rootfs (with buildah slack), gzips, and PUTs it to the generic package.
Rollout note: default=pull means a launch 404s until an artifact is published;
until the Gitea packages endpoint is enabled + an artifact published, use
BOT_BOTTLE_INFRA_BUILD=local. Freeze/migrate's remaining docker use is a
separate PR.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UoEZHDjv84ChoZbozQERhJ
