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
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vm	vmbox: disposable Arch VM sandbox for destructive system tests	2026-08-22 20:47:56 +02:00