Four checks, all of them before a single byte is written, because this is the
only moment the script still has the option of not overwriting a disk.
The expensive one is "is this actually a rescue system". It demands POSITIVE
evidence rather than the absence of a counter-argument: a rescue system runs
from RAM, so its root is tmpfs, an overlay or a ramdisk, and an installed
system has a real partition there. A running pveversion is refused outright —
that is a hypervisor with customers on it. Mounted partitions of real disks are
refused too, because at that point the script cannot tell an empty machine from
someone's data.
There is deliberately no flag to skip the check. Such a flag gets used exactly
once, on the evening it should not have been. A rescue system this does not
recognise belongs in the runbook, not in a bypass.
The disk floor is written as arithmetic rather than a number, because the repo
has no threshold to borrow — plans live in the database, not in
config/provisioning.php. Template ~20 GB, Proxmox and its swap and backups
~20 GB, one smallest customer ~50 GB, rounded up to 100. It is explicitly not
capacity planning; HostCapacity and reserve_pct do that after registration.
This only turns away the machine the whole thing cannot fit on.
Network and clock come from one plain-HTTP HEAD, deliberately without TLS —
otherwise a wrong clock would be checking itself and would report a certificate
error instead of the time. Where `date -d` is missing (busybox), the clock is
NOT checked and the report says so: a check that silently waves things through
is worse than none, because it stops the next person from looking. That is the
same lesson R19 records about ->timezone(config('app.timezone')).
Verified here, in both directions where a direction existed. On this VM (root
on /dev/sda1, 80 GB, /dev/kvm present): refuses with three findings at once,
exits 1, writes nothing. In a debian:13-slim container (root on overlay, no
/dev/kvm): the overlay root is accepted as rescue-like and the missing
/dev/kvm is caught, which is the abort case the plan names. Against a receiver
serving a Date header two years off: 63074141 seconds of drift, refused, with
the exact `date -u -s` line to fix it. Step 2 stays unticked — none of these is
a rescue system on a dedicated server.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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