OnFailure fires when a unit enters failed. A unit that keeps re-earning its
retries never enters failed, so the alarm never fires for it. svos-dev warned
this was the consequence of the interval divergence; measuring it showed the
gap is most of the box.
MEASURED: a unit shaped like booth/althing-po-herald (Restart=always,
RestartSec=5s, burst 5, interval 10s) ran 9 restarts over 45 seconds cycling
active/activating and NEVER reached failed. No alarm would have fired.
Covered: the 7 timer-driven oneshots (Restart=no, so any failure lands in
failed immediately) and svos.service (burst 3 per 5min -- it genuinely gives
up). NOT covered: ten daemons that flap instead, and hermes-gateway, whose
start limiting is disabled outright.
svos.service's divergent 5min window is deliberate and load-bearing (operator
ruling 2026-09-11, 'fatal both ways'). NOT to be harmonised: that would restore
the flapping the ruling forbids AND silence the alarm on the one daemon it
currently works for. Whether the OTHERS move to 5min is a behaviour change for
ten services and an operator call.
Also recorded, svos-dev's framing of the two installer bugs: a tool that
enumerates 'things that are fine' and acts on them has selected against its own
subject. Neither bug failed randomly -- both were anti-correlated with purpose,
working better the healthier the fleet looked.
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