* fix: drain guests on a plain target stop, not just restart
`systemctl is-system-running` cannot tell a plain `systemctl stop
spinifex.target` apart from the stop half of a restart -- both report
`running`, and the old `--only-if-host-stopping` gate skipped the drain
for both. That left guests running with no QMP shutdown and no volume
unmount while predastore/viperblock stopped underneath them, so a real
stop discarded any writes still in flight.
Add a second signal: `systemctl list-jobs` shows a pending START job for
spinifex.target during a restart (the target's stop leg resolves
instantly, since it owns no processes) or a pending RESTART job for
spinifex-shutdown.service itself when that unit is restarted directly
(PartOf propagates target-to-member only). Renamed the flag to
`--unless-restarting` to match: drain on a real shutdown or a plain
stop, skip only when one of those jobs shows a restart is already
queued. Any step systemctl can't answer fails toward draining, and a
skipped drain now warns loudly (naming each instance still running) so
an operator sees the risk in the journal instead of discovering it via
`ps`. `--only-if-host-stopping` stays as a deprecated, still-functional
alias so a partial upgrade between unit file and binary doesn't break.
* fix: retry the local drain GATE/DRAIN ACK instead of failing on first miss
A drain that fails at GATE is indistinguishable from a skipped drain from
the guest's perspective: it keeps running while storage goes away
underneath it. Stopping spinifex.target shortly after a restart hit exactly
this: the daemon had not finished re-subscribing to NATS, so the ACK
request came back with zero subscribers and NATS bounced it back near-
instantly ("no responders"), which is why the failure logged in about a
second despite --timeout=120s. collectLocalShutdownACK now retries with
backoff bounded by the phase timeout instead of failing on the first bounce,
and an exhausted retry budget logs at ERROR and names the guests still
running via a severity-aware refactor of warnIfGuestsLeftRunning, so a
failed drain is unmistakable in the journal rather than silent.
* fix: reap idle nbdkit concurrently and re-derive viperblock's stop budget
KillMode=process made viperblockd the sole reaper of nbdkit on SIGTERM, but
shutdownVolumes reaped them one at a time and TimeoutStopSec was never
re-derived for that change. With several mounted volumes the serial loop
blew past the 30s budget, systemd SIGKILLed viperblockd mid-loop, and
whichever nbdkit hadn't been reaped yet was orphaned.
Fan the per-volume utils.KillProcess calls out concurrently so the reap
costs one worst-case nbdkit, not N of them summed, and raise
TimeoutStopSec to 150s to strictly exceed that single-volume worst case
(120s KillProcess grace + nbdkit's own 20s drain + headroom). Add an
invariant asserting the two stay in that relationship, and a test proving
the reap is actually concurrent (fails against the old serial loop).
* docs: document the host and guest lifecycle contract
States what happens to running guests for every host lifecycle event: reboot, target restart, target stop, daemon restart, daemon crash, power loss and a coordinated cluster shutdown. Records the older-release behaviour where a plain target stop left guests with no data path, and how to tell which behaviour a node has.
Josh Siviour