The Discord template printed `value: {{ .ValueString }}` unconditionally, so a
notification carrying no value rendered as "value:" with nothing after it —
which reads as a value that failed to compute rather than one that was never
applicable.
ValueString is only populated when the notification came from an evaluation
that produced refIds. An instance resolved by Grafana's staleness handling has
none: no evaluation returns it again, so the state manager expires it. That is
triggered by a rule title change, since the title becomes the alertname label
and the old label set is orphaned — renaming ProdWorkerContainerSilent to
ProdWorkerHeartbeatMissing did it and posted exactly that message.
Guarding the whole line rather than the substitution: an unguarded
{{ .ValueString }} is harmless on its own, printing the label is the bug.
Verified by executing both templates through text/template with ValueString
set and empty: parses and executes clean, populated output is byte-identical
to the previous format, empty case omits the line.
The estate had zero alert rules. The only contact point was Grafana's factory
default pointing at the literal string <example@email.com>, and beta's
untracked compose override routed Grafana's SMTP at prod's Postfix — so
alerts, had any existed, would have been delivered by the box most likely to
be on fire. Prod served 86 5xx in 24h including five /healthz failures and
nobody was told.
Alerting (deploys to beta, which is where Grafana runs):
- 12 Loki-based rules. There is no Prometheus in this estate and Loki is the
only datasource, so every rule is log-derived.
- Thresholds come from a 24h backtest that happens to contain a real ~20min
prod outage at 04:20Z. Absolute counts, not ratios: prod runs ~7 req/min, so
one bad request is 1.4% and a ratio alert would scream all night. The 5xx
burst rule fires on the outage's 45 and 22 buckets and on nothing else in
the day; the largest benign bucket all day was 5.
- Routed to a new private #ops-alerts channel, not to any existing channel —
#weather-events, #announcements and #prod are product surfaces that notify
real subscribers.
- AlertingWatchdog is a dead-man's switch; its value is its absence.
- Delivery is proven, not assumed: the rules were provisioned into a throwaway
Grafana against beta's live Loki and a real alert arrived in Discord. This
matters because GET /api/v1/provisioning/contact-points returns [REDACTED]
for the URL — a contact point holding an uninterpolated env var looks
perfectly healthy and pages nobody. The only proof is a message arriving.
CI gains a structural check, because the existing one only proves YAML parses:
an alert rule whose condition names a missing refId is valid YAML, provisions
cleanly, and never fires. It also hard-fails on a literal Discord webhook in
the repo. Verified against all three breakages deliberately introduced.
Postfix supervision:
- The 13h outage was a boot-ordering race, not a Docker renumbering: postfix
started at 08:09:49, wg0 came up at :51, postfix fataled at :52 on a missing
docker_gwbridge address, and dockerd did not finish starting until 08:10:16.
Stock postfix@.service is ordered only After=network-online.target and ships
no Restart=, so one lost race became a permanent outage.
- An ExecStartPre gate now blocks up to 60s until every inet_interfaces
address actually exists, which absorbs the transient case inside a single
start attempt. That makes bounded retry correct: 5 attempts in 600s, then
failed — a genuinely broken config reaches a visible failed state in ~100s
instead of re-fataling every 15s forever.
- A 5-minute watchdog timer retries indefinitely and runs reset-failed, so
"failed" still self-heals. Worst case is ~5 minutes, not 13 hours.
- Wants=, not Requires=: a dockerd failure must not take down the loopback and
mesh listeners that do not depend on Docker at all.
Health checks must read config with `postconf -c`, never postmulti/postqueue/
postfix — those three RESOLVE inet_interfaces and so fatal precisely when an
address is missing, which made the first version of this check report
status=ok bound=0/0. A health check that fails open is worse than none.
DEPLOY.md carries the monitoring contract, including that systemctl is-active
postfix is a known-false signal: postfix.service is a wrapper whose
ExecStart=/bin/true, so it reports active forever while the real postfix@-
instance is failed with zero listeners. Reproduced live.
Known gap, documented not fixed: Alloy ships Docker stdout, Caddy files and
app JSONL, not journald — so no Postfix line reaches Loki and the mail rules
cannot fire until loki.source.journal is added.
Claude-Session: https://claude.ai/code/session_0182KTMrsTHJc3TcewCatJFY
One root workflow set replaces the four repos' copies (deleted -- root-only
is where Forgejo reads them, and dead copies are a trap): per-domain
build-push with explicit image paths (emi/thermograph/backend|frontend; the
old github.repository-derived path collides in a monorepo), path-filtered
per-domain beta/prod/dev deploys, a domain-input reusable build check, a
single always-reporting PR gate (path-filtered required checks deadlock
auto-merge), a new infra-sync pipeline (host checkout + secrets render on
infra/** pushes), and ports of secrets-guard / ops-cron /
observability-validate to monorepo paths.
