CI runners with a whole VM

Why it pays

• Tests that need a real machine Docker Compose stacks, systemd services, kernel modules and emulators work as they do in production.
• Fresh every time Each job starts from a template and is deleted afterwards. Nothing leaks between runs.
• Per-second billing A four-minute job pays for four minutes, with no per-minute rounding.

Step by step

1. Build a CI template

   Install toolchains and warm caches once.

   CLI

   harebox new --name ci-base
   harebox exec current -- ./install-ci-tools.sh
   harebox template save current --name ci-base

2. From any CI: run one job in a fresh VM

   One command starts a sandbox from your template, runs the job, deletes the sandbox and exits with the job's own code. --keep-on-failure keeps a failed job's machine for inspection, and a cancelled job still cleans up.

   CLI

   harebox run --from ci-base --size large --keep-on-failure -- make test

   Python

   box = hb.create(template="ci-base", ttl_seconds=1800, name="ci-job")
   try:
       result = box.run("make test")
       raise SystemExit(result["exit_code"])
   finally:
       box.delete()

   TypeScript

   const box = await hb.create({ template: "ci-base", ttl_seconds: 1800, name: "ci-job" });
   try {
     const r = await box.run("make test");
     process.exitCode = r.exit_code ?? 1;
   } finally {
     await hb.deleteSandbox(box.id);
   }

3. Later: GitHub Actions labels

   Planned: once the HareBox GitHub App is connected, a runs-on label picks the machine size. It isn't connected yet, so use harebox run from any CI today.

   GitHub Actions

   # .github/workflows/test.yml
   jobs:
     test:
       runs-on: harebox-large
       steps:
         - uses: actions/checkout@v4
         - run: docker compose up -d && make test

Tips

• Keep deployments on Shared. Spot costs the same and can be preempted with two minutes' notice.
• Use --ttl on every CI sandbox so a crashed pipeline can't leave one running.
• Nested KVM lets a job boot an Android emulator or a Firecracker microVM.