rapp-canned-prompts/docs/evidence/RCP-WP-0002-T04-first-deployment-2026-09-08.md
tegwick caf3912d1b Fix the lease watcher, and record that three checks were themselves wrong
The first lease watch returned FAILED on one sample of 21. That sample was the
instrument: it treated an empty kubectl result as not-ready, so a transient API
hiccup was recorded as an outage. The service returned zero 503s across the
window, with a readiness probe every 5s and 46 minutes of uptime past a
30-minute lease.

Not overriding the verdict by argument — a verdict that can be talked around is
worth nothing. The watcher now distinguishes a failed query from a failed
service and corroborates against the kubelet's probe history, which samples far
more often than once a minute. Promoted from scratch into tools/ so it is
reviewable and re-runnable.

Three checks in this rollout were defective in the same way: live-image-digest-match
degrading to 'not pinned' while a digest was pinned, check_readiness reporting
'database unreachable' for a reachable but unmigrated database, and this
watcher. A verification step that cannot fail correctly is worse than none,
because it is trusted.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bjefh8NUiEiahN4JLwoSKM

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 388925@bnt-lap001
Assistant-Session: 3507023f-e0fd-4a1e-9d90-a0d4217d1502
2026-09-08 09:48:06 +02:00

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Markdown

# RCP-WP-0002-T04 — first deployment evidence
**Date:** 2026-09-08
**Image:** `sha256:14c7b92f20d63f2e70ea17b0b45d3c483521fbbaf14ee5bc277fa541e10452e2` (tag 0.1.5)
**Cluster:** railiance01 / k3s, namespace `canned-prompts`
**Schema:** alembic revision 0002, applied by the migration Job as `canned_prompts_migrate` with `SET ROLE canned_prompts_owner`
## `tools/smoke.sh`
```text
PASS external-secrets-ready:canned-prompts-postgres-runtime
PASS external-secrets-ready:canned-prompts-postgres-migration
PASS private-service-only:type
PASS private-service-only:no-ingress
PASS networkpolicies-present
PASS live-image-digest-match
--- service-level (/home/worsch/canned-prompts/service/tools/smoke.py) ---
PASS liveness-ok 200 {'status': 'ok'}
PASS readiness-ok 200 ok
PASS state-health-ok 200 connected
PASS migration-at-head running 0002, expected 0002
PASS index-queryable 200
PASS registry-queryable 200
all 6 checks passed
all deployment checks passed
```
## Read-only posture verified
`POST /packages` returns **503**, not a 500 and not an acceptance:
```json
{"detail":"publishing is not configured: this service has no publisher identity, so it cannot tell who is calling and refuses writes rather than accepting anonymous publishes (§ 20.1)"}
```
This is the intended state. `creds/canned-prompts-publish` was deliberately not issued (rapp-postgres receipt, 2026-09-08). The read surface answers normally: `/packages` and `/index` both return empty result sets rather than errors.
## Defects found and fixed during this rollout
| Defect | Consequence had it shipped |
|---|---|
| `env.py` read `database_url` rather than `resolved_database_url` | Migration could never run in the cluster, where the credential is a mounted file |
| `SET ROLE` opened an implicit transaction Alembic then nested inside | Every migration logged as applied and was silently rolled back — an empty database reported as success |
| Egress NetworkPolicy selected `name`, not `part-of` | Migration Job matched only the default-deny; it succeeded once purely because it ran before the policies existed |
| Missing optional publish-token file treated as a hard failure | The documented read-only posture returned 500 instead of an explanatory 503 |
| `smoke.sh` extracted the digest with a line-offset `grep` | `live-image-digest-match` silently degraded to "not pinned" and could never have passed |
## Correction: `verified` was recorded too early
I set `readiness_state: verified` after a passing smoke run, then found the
deployment `0/1` eight hours later. It is back to `deployed` until it has been
observed across a credential rotation.
**Cause.** Platform credentials are 30-minute leases, not passwords. The
service read the mounted URL once at start-up and never again, so External
Secrets kept the file current while the engine held the URL it booted with.
Every reconnection after the first lease expiry used a credential the database
had already revoked. `/readyz` reported it correctly —
`database unreachable: OperationalError` — and the pod sat unready for eight
hours without ever being restarted, because liveness is deliberately
independent of the database.
**Fix (0.1.5).** The engine now re-reads the credential for every new
connection via a `do_connect` hook, and `pool_recycle` is 900s so a pooled
connection is retired well inside the 30-minute lease. Only the username and
password are taken from the refreshed URL; host, port and database come from
the engine, so a malformed refresh cannot silently redirect the service.
**What this says about the verification itself.** A smoke run inside the first
lease window cannot distinguish a service that works from one that works *once*.
The criterion for `verified` is therefore observation across a full rotation,
not a passing check at a single instant — an availability property is not
provable by one sample.
## The watcher was also wrong
The first lease watch returned **FAILED** on one sample out of 21. That sample
was the instrument, not the service: it treated an empty `kubectl` result as
"not ready", so a transient API hiccup was recorded as an outage.
The service had returned **zero** 503s across the whole window. The readiness
probe fires every 5s, so a genuine two-minute outage would have left roughly
twenty-four of them, and the pod ran 46 minutes past a 30-minute lease with no
restarts.
I did not override the verdict by argument — a verdict that can be talked around
is worth nothing. The watcher is fixed (`tools/lease-watch.sh`) to distinguish
a failed *query* from a failed *service*, and to corroborate its own sampling
against the kubelet's probe history, which is a far better instrument than one
sample a minute. Then re-measured.
**Three checks in this rollout were themselves defective**, all the same shape —
unable to distinguish their own failure from the failure they were watching for:
| Check | How it lied |
|---|---|
| `live-image-digest-match` | line-offset `grep` returned empty; reported "not pinned yet" while a digest was pinned |
| `check_readiness` (earlier) | one `except` reported "database unreachable" for a reachable but unmigrated database |
| lease watcher v1 | empty `kubectl` output counted as an outage |
A verification step that cannot fail correctly is worse than none, because it is
trusted. That is the durable lesson from this deployment, more than any single
defect it found.