utils/vmbox/lib
Krzysztof kuhy Rudnicki a2d672f7fd vmbox: disposable Arch VM sandbox for destructive system tests
Much of testsAndMisc/linux_configuration cannot be tested on the host: 15
files use `chattr +i` (so a bad test is not simply revertable), the shutdown
installers write units that power the machine off, and boot_recovery installs
pacman hooks. The repo's own CI says as much -- its Ubuntu job runs only the
side-effect-free tests, noting the rest "drive pacman, /etc, systemd or adb".

vmbox runs them in a throwaway Arch guest and verifies the result from the
HOST, which is the part that is not obvious: a successful shutdown kills the
connection carrying the report, and ssh returns 255 for a clean poweroff, a
crash and a dropped link alike. So the verdict comes from two artefacts that
outlive the VM -- a QMP event log written by a recorder attached at launch
(attach later and qemu has already exited), and the serial console log.

Five outcomes are distinguished: clean poweroff (SHUTDOWN guest:true plus a
serial tail reaching "reboot: Power down"), dirty stop, guest-reset (rebooted
instead of powering off), GUEST_PANICKED, and hung. A POWERDOWN event proves
nothing -- it means the request was delivered, not that anything acted on it.

Reset is a qcow2 backing-file trick: the golden image is built once and sealed
(chmod 444 plus a sha256 sidecar verified on every launch, since booting the
base would silently invalidate every overlay), and each sandbox is a thin
overlay, so reset is rm + recreate. No root anywhere -- user-mode networking
with per-VM forwarded ssh ports, and a socket multicast segment for VM-to-VM.

The guest clock is pinned and re-applied on every launch, because the shutdown
installers gate on a 21:00-05:00 window; NTP is masked in the image or it
silently undoes the pin. Repos are cloned from a read-only share scoped to an
explicit directory, never $HOME, and credentials are sentinel values.

`vm build` ends by booting a throwaway sandbox off the sealed image and
refusing to ship if ssh does not answer. Several distinct faults produced an
identical "boots fine, connection reset" symptom; checks inside the build VM
only prove state at seal time, so the gate has to be an end-to-end boot.

Tests: 8 bats cases over the verdict table and name/meta/serial handling;
shellcheck and ruff clean; every file within the 250-line cap.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdyMBGCrGVGDWtJ9xe48f3
2026-08-22 20:47:56 +02:00
..
base.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
common.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
launch.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
overlay.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
qmp.py vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
recorder.py vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
repo.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
run.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
screenshot.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
seed.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
smoke.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
ssh.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00
verdict.sh vmbox: disposable Arch VM sandbox for destructive system tests 2026-08-22 20:47:56 +02:00