# REPORT — F-CRIT-1 + F-A1: one alarm that never fired, one that fired wrongly (v0.179.0) (2026-07-28) **Overwritten** per the standing rule. Controller **v0.178.0 → v0.179.0**. Both Campaign 8 findings, fixed together because both are "the alarm is wrong" and both live in `internal/quiesce` plus its `classifyRunStates` consumer. No wire/contract change; no agent behaviour change (its 409 is correct and was left alone — only a wrong comment there was corrected). ## Baselines (reconfirmed, not copied) Controller `0.178.0` live on both boxes; agent `0.106.0`; `felhom-controller 8f46495`, `felhom.eu d0cec9d`, `felhom-agent af1c21a`, all clean. --- ## F-CRIT-1 — a failed app restart never alarmed. Two independent causes. ### Cause 1 — the outcome was thrown away `restartAll` returned nothing; a failed `StartStack` was logged and dropped on the spot, so no caller could learn a customer's app had not come back. It now **returns the stacks that failed**, and both call sites (the cycle's unquiesce and crash recovery) record the result via `noteRestartOutcome`. ### Cause 2 — a documented invariant the quiesce path had made false `classifyRunStates` whitelists `StateStopped` because v0.164.0 correctly refused to alarm on deliberate user stops, resting on I1: *"StateStopped means deployed, deliberately stopped by the user."* **The quiesce loop stops stacks by the same `docker compose down` path**, so a stack it stopped and then failed to restart is also `StateStopped` — byte-identical on the Docker side — and was whitelisted into total silence. No state test can separate them; they *are* the same state. The distinguishing fact is that the loop **tried to restart it and could not**, now surfaced by `Loop.FailedRestarts()`. That set is the only thing that lifts the whitelist: ```go userStopped := st.State == stacks.StateStopped && !failedRestart[st.Name] down := stacks.IsDownState(st.State) && !userStopped && !quiesced[st.Name] ``` The flag is only ever consulted for an already-down stack, so a stale entry cannot manufacture an alarm on a healthy app; it clears the moment a later restart of that stack succeeds. ### Why the existing tests missed it R-97b's Scenario F asserted that **suppression expires**. It never asserted that **an alarm follows**. Suppression lifted correctly and the whitelist ate the alarm one layer down — a green, red-proofed suite over a production path broken two independent ways. That is why §5 exists. --- ## F-A1 — a correct refusal reported as a failure HTTP 409 from `POST /backup` is the agent's R-85 single-flight gate refusing while a restore-test holds it. The start path had no 409 branch, so it called `noteTierFailure`: breaker armed, `whole_guest_backup_failed` emailed. At real cadences a ~12-minute restore-test against a daily backup collides roughly once per 420 guest-days — about **every 4 days on a 100-guest fleet** — training the operator to ignore the alarm and quietly undoing R-97a. 409 is now contention: `agentapi` returns a typed `*StatusError` on POST (it was `fmt.Errorf`, i.e. string-only), the adapter maps 409 → `quiesce.ErrTierBusy` at the same seam that maps 404 → `ErrTiersUnsupported`, and the loop defers. No breaker, no event, no email; the tier stays **DUE**. ### The two traps, and the bounds chosen **Silence.** "Just ignore 409" would let a wedged restore-test block backups forever with nobody told. So contention outliving **`contentionAlarmAfter` = 3h** raises its own signal, headlined **BLOCKED**, not FAILED. The bound is set by the agent's own ceiling, not taste: its PBS restore-test task is capped at **120 minutes** (`config.RestoreTestPBSRestoreTimeout`, default 120m), after which the agent times out and releases the gate itself — so contention outliving that is a *stuck* gate, not a busy one. 3h adds an hour of margin for teardown and 5-minute poll granularity, and is 15× the longest contention actually observed (12m01s). **App thrash.** Removing the failure treatment also removes the breaker's deferral, which had been (accidentally) preventing a re-quiesce every 5 minutes. Without a replacement the customer's apps would be stopped and restarted on **every poll** for the whole restore-test — worse than the bug. A contended tier is therefore dropped from the due set **before anything stops**, on **`contentionRetryAfter` = 15m** (longest observed restore-test 12m01s; the agent's local restore-test wait is 10m), capping churn at 4/hour instead of 12/hour. --- ## Red-proofs — all six observed failing | # | red-proof | observed failure | |---|---|---| | 1 | restore the unconditional `StateStopped` whitelist | `a stack that FAILED to restart is silent (Down=false) — this is F-CRIT-1` · `absent from the dashboard dead-list` | | 2 | treat every `StateStopped` as a failed restart | `a deliberate user stop alarmed — that is the v0.164.0 regression this must not reintroduce` · `stopped alarmed with no failed restarts` | | 3 | make `restartAll` drop its errors again | `restartAll returned [], want exactly [immich]` · `want immich to be recorded as a failed restart, got map[]` | | 4 | remove the 409 branch | `runOnce: start backup on (untargeted): quiesce: tier busy — a concurrent heavy operation holds the agent: agentapi: POST /backup: HTTP 409` | | 5 | treat all errors as contention | `breaker did not arm on a real 500 (failures=0) — a real 500 was swallowed as contention` · `operator was NOT notified of a real failure` | | 6 | remove the contention alarm bound | `no alarm after 3h0m0s of unbroken contention — that is a silence path, the exact thing this fix must not create` | `go build`, `go vet ./...`, `go test ./...` — all green, run separately from the commit. (Red-proof 6 first produced a *compile* error, which is a weaker proof; it was redone so the code compiles and the alarm simply never fires.) --- ## §5 — LIVE replay of BOTH findings on demo-hp, with the hub DB as arbiter ### F-CRIT-1 One image tag made unresolvable, then a normal quiesce: ``` 06:54:30 unquiescing (snapshotted (early resume, last tier)): restarting 1 stack(s) 06:54:36 [ERROR] [quiesce] restart paperless-ngx: starting stack paperless-ngx: exit code 1 containers: 0 ``` | moment | result | |---|---| | during grace (06:54:59) | 0 events, 0 banner markers, 0 pushes — **suppressed** | | grace expiry | 06:54:30 + 180s = **06:57:30** | | **06:57:39** | `PushEvent: type=app_start_failed severity=warn` → hub `Event from demo-hp: app_start_failed` | | dashboard | `alert-icon … Telepített alkalmazás nem fut: Paperless-ngx (stopped)` | The banner names the `(stopped)` state explicitly — the whitelist was lifted, not bypassed. Nine seconds after the window closed, on the first scan. ### Scenario B live — the inverse, same box The app was restored to healthy, then stopped **deliberately** via the UI path: ``` containers after deliberate stop: 0 stack state: stopped deadapp scans during the silent window: 9 app_start_failed events for demo-hp TODAY (events table) = 1 ← still just the failed restart ``` Same box, same `stopped` state, opposite outcomes — driven purely by whether the loop failed to restart it. The 9 scans are the positive observable that the silence is suppression, not a dead detector. ### F-A1 A restore-test was forced to hold the gate, then a backup triggered: ``` agent: backup refused — a heavy operation is already in flight busy=restore-test (both tiers) controller: tier local is BUSY — the agent refused ... This is contention, NOT a failure: the tier stays due and retries in 15m0s (contended for 0s) controller: tier felhom-pbs is BUSY — ... same controller: unquiescing (last tier is busy — deferring to a later cycle): restarting 1 stack(s) ``` ### Scenario G live — the inverse, same box, same event type A **real** transport failure (PBS path dropped at nft, not a 409): ``` 07:41:47 [WARN] tier felhom-pbs: backup job ... failed 07:41:47 [WARN] tier felhom-pbs has now failed 1 time(s) in a row — deferring by 15m0s 07:41:47 [INFO] Event pushed: whole_guest_backup_failed (error) — Whole-guest backup FAILED on the felhom-pbs tier ``` ### The hub DB, not the logs — the decisive numbers | injection | `whole_guest_backup_failed` sent(operator), demo-hp | |---|---| | baseline before either replay | **8** | | after the **409** contention replay | **8** — zero spurious emails | | after the **real failure** (Scenario G) | **9** — fired 09:41:48 CEST | Breaker arming lines since deploy: **0** for the 409, **1** for the real failure. Same box, same day, same event type; the only difference is 409 versus a genuine error. ### Scenario F live After contention cleared, the backup **ran and both tiers succeeded** (`tier local: done`, `tier felhom-pbs: snapshotted`) — contention did not poison the tier. The armed breaker from Scenario G was then cleared by a successful backup, with `whole_guest_backup_recovered` emitted. --- ## Deployed & fleet state `felhom-controller 0.179.0` on **demo-hp** and **demo-felhom**, both healthy. demo-felhom 15/15 containers, demo-hp 8/8, zero unhealthy, no nft leftovers, cadences untouched (`local 0`, `rt 302400`, `felhom-pbs 604800`), agent `0.106.0` on both. **demo-felhom had no injection and produced 0 event/alarm lines since its deploy** — the fix is not chattering on an untouched box. One leftover of my own making was cleaned up: Scenario G's block failed a restore-test mid-flight, which leaked scratch guest `990000` — the already-filed F-LEAK/R-99 behaviour (a failed restore-test cannot destroy its own scratch guest, 403 `VM.Allocate`). Destroyed; `pct list` shows only 9201. ## Comments corrected (three of the six catalogued) - `classifyRunStates` I1 — now states what `StateStopped` actually means and names the quiesce path. - `quiesce.go`'s "would record a spurious failure" — records that this was not hypothetical until now. - agent `inflight.go`'s "a caller that cannot acquire DEFERS" — records that this was true of the restore-test caller and not the backup caller; fixed controller-side. Standing rule added to **both** copies of `CLAUDE.md` (live + versioned): *a comment asserting an invariant needs a test pinning it, or it is a wish*, with all six instances catalogued. ## NOT yet live-validated (carried forward, minus what this closes) - Fault 4 — restic transport interruption; four injection approaches defeated by guest-bridged networking. **Still the most valuable follow-up**: F-CRIT-2 answered the phantom question for PBS and it remains open for restic. - **R-99** — prune never removes phantom snapshots (no retention bug; they accumulate). - **F-LEAK** — a failed restore-test cannot destroy its own scratch guest; observed again here. - Fault 12 (host reboot mid-backup); the three-way backup+restore-test+GC overlap; the agent's DR bring-up path (`ModeDRGuestLoss`), still read-only-verified. - `contentionAlarmAfter` (3h) itself — proven by unit test with an injected clock, **not** live; a live proof needs a gate wedged for three hours.