CNPGNoRecentBaseBackup's own remediation hint said `kubectl get backup`.
On this cluster longhorn.io, postgresql.cnpg.io and velero.io each register
kind Backup, so the bare short name resolves to Longhorn's empty set and
prints 'No resources found' while CNPG backups exist. An on-call following
the alert that fires BECAUSE backups look stale would have been told, with
authority, that no backups exist at all — and might re-bootstrap a database
over good ones. Fully qualify it.
Co-Authored-By: Claude Opus 5 <[email protected]>
CNPGNoRecoverabilityPoint has been firing continuously on prod against six
pods — keycloak-db-1/-3, nextcloud-db-1/-3, semaphore-db-1/-3 — i.e. exactly
the REPLICAS of all three Clusters, while the databases themselves are fine:
every Cluster reports firstRecoverabilityPoint=2026-09-07T07:0x, a
lastSuccessfulBackup within the last few hours, ContinuousArchiving=True and
LastBackupSucceeded=True.
Root cause is aggregation scope, not archiving. `cnpg_collector_first_recoverability_point`
reads the backup CATALOGUE, which only the primary owns; a replica reports a
hard 0 for as long as it is a replica. The metric carries no cnpg.io/cluster
label (its label set on prod is container/endpoint/instance/job/namespace/pod),
so `max by (namespace, pod)` evaluated each replica as its own subject and an
`== 0` comparison then held forever. The rule went from correct to permanently
wrong the moment the Clusters went to `instances: 3`; nothing about the
expression changed.
WHY THIS IS WORSE THAN HAVING NO ALERT. An alert that is always firing has
zero information content: its value is identical in the healthy state and in
the failure state, so it cannot distinguish them. It is worse than silence in
two specific ways. First, it trains the operator to delete the notification on
sight, so the day a base backup genuinely stops the seventh identical email is
discarded with the other six — the alert actively MASKS the failure it was
written to catch, which for a DR alarm means discovering the loss at restore
time. Second, it is indistinguishable from a broken alert, so nobody can tell
whether the absence of new alerts means health or means the rule rotted. This
file exists because a real 38-hour archiving failure told nobody; a rule that
cries wolf about six healthy replicas rebuilds exactly the blindness it was
supposed to remove. This repo has been here before — see the permanently-firing
critical VPNTunnelDown post-mortem in platform/monitoring/alerts.yaml.
Fix: group by (namespace, job) and aggregate `pod` away. The CNPG operator
creates one PodMonitor per Cluster, named after the Cluster, in the Cluster's
namespace, so prometheus-operator derives job="<namespace>/<cluster>" —
keycloak/keycloak-db, nextcloud-db/nextcloud-db, semaphore-db/semaphore-db —
which identifies the CNPG Cluster uniquely. `job` rather than bare `namespace`
deliberately: namespace alone works today (one Cluster per namespace, verified
live) but would let two Clusters in one namespace mask each other, since the
healthy one's non-zero value would satisfy `max` for both. The alert now
states what its summary always claimed — this CLUSTER has no recoverability
point — and fires only when no instance of that Cluster reports one.
Proven live against prod Prometheus, read-only (promtool query instant):
OLD max by (namespace, pod) (...) == 0 -> 6 series, and 6 ALERTS firing
NEW max by (namespace, job) (...) == 0 -> empty
The new expression is not vacuous: forcing the metric to 0 for one cluster's
primary only yields exactly one series, {job="keycloak/keycloak-db"}, so a
genuine single-cluster loss of DR still alerts, per cluster. `promtool check
rules` passes on all 5 rules.
CNPGNoRecentBaseBackup carried the same defect and is fixed the same way.
`cnpg_collector_last_available_backup_timestamp` is also primary-only: on prod
the primaries read 3.1h/2.1h/0.1h old while all six replicas read 0, i.e.
time()-0 = ~56.7 YEARS. It was not firing only because the `> 0` guard was
load-bearing — a single clause was all that stood between this rule and six
more permanent false positives, too thin a margin for a DR alarm. Aggregating
`pod` away removes the dependence: `max` takes the primary's timestamp as the
cluster's answer, and the guard now means "this cluster has had at least one
backup". Verdict unchanged live (old empty, new empty).
The other three rules were audited and deliberately left on `by (namespace, pod)`:
* CNPGWALArchiveBacklog — every instance reports archive_status and the shape
is `> 0`, so a replica at 0 never fires and no pod can mask another; `pod`
names the instance whose archiver is stuck.
* CNPGWALVolumeNotRecycling — per-pod is REQUIRED, not merely safe:
aggregating it away would compare one instance's WAL count against
another's max_wal_size.
* CNPGMetricsCollectorErroring — unchanged in meaning AND grouping. Its
grouping is already correct: cnpg_last_error is genuinely per-instance, and
prod proves it discriminates rather than tracking role — all three
nextcloud-db pods report 1 while all six keycloak/semaphore pods report 0.
It is a true positive (the nextcloud 42501 CONNECT grant) owned by separate
work; nothing here silences or rescopes it.
The general rule, recorded in the file: `== 0`/staleness shapes must aggregate
`pod` away or every structurally-silent pod fires forever; `> 0` shapes are
safe per-pod and keep the instance name.
Co-Authored-By: Claude Opus 5 <[email protected]>
Minimal prod delivery, authored directly on main (= prod's live revision d1a6628)
rather than by merging work/prod-standup-campaign. That branch carries the DNS apex
inversion, which would have set prod's BASE_DOMAIN to home.keithjackson.dev; prod
runs external-dns with policy: sync and txtOwnerId: prod, so it would have begun
rewriting apex records dev owns while the non-k3s prod still serves 443 there.
Operator sequencing is "dev migrates first". Nothing under clusters/ is touched
here at all, which is what makes this safe to land now.
Also deliberately EXCLUDED, because prod's live cluster-vars has no CNPG_BACKUP_PATH
key and StrictPostBuildSubstitutions would fail the whole tier: the R2 rework of
platform/velero/ and the CNPG destinationPath changes. Those land as
feat/r2-backup-prod together with the endpoint and bucket knobs.
WHAT THIS FIXES
1. Nothing was watching CNPG. All three prod databases have run since bootstrap with
ContinuousArchiving=False and firstRecoverabilityPoint=null, and no alert existed
anywhere. Because archive_mode=on and the archive command fails, Postgres refuses
to recycle WAL: keycloak-db holds every segment ever written (257 MiB on a 5 GiB
volume, ~6.8 MiB/h) — roughly 29 days to a disk-full PANIC on the cluster's SSO
database. Found by hand, 38h late. CNPGWALArchiveBacklog would have fired within
the hour, and evaluates to 3 firing series on prod today.
Rules key on cnpg_collector_* rather than cnpg_pg_stat_archiver_*, because
nextcloud-db's exporter cannot log in to its own database (permission denied for
database "nextcloud", both clusters) so the pg_stat_archiver family does not exist
for it — the obvious metric would have been blind to one database in three.
2. No PVC outside namespace=monitoring had any fill alert. New rules are partitioned
by namespace so they cannot double-fire with MonitoringVolumeFillingUp, pinned to
job="kubelet" (the apiserver copy of the same series reports namespace=default),
and guarded by inodes > 0 — block-mode PVCs such as unifi-rootdisk report
available=0 forever and would otherwise have fired critical permanently.
3. VPNTunnelDown could never clear on a cluster with no gateway node; it has been
firing critical on prod since 2026-09-05. Now guarded so prod self-arms the moment
a node carries the egress-gateway label, with dev's behaviour unchanged today.
4. The Keycloak realm import fails OPEN: an unresolved placeholder is stored
LITERALLY and the import still reports success, then sits at Done=True and never
re-runs. On 2026-09-06 all 12 prod OIDC clients held the literal
$(env:..._CLIENT_SECRET) string and every SSO login failed, while every signal was
green. The CronJob is the level-triggered correction; two alerts make its silence
observable. Repaired live already — this stops it recurring.
Also: the R-NET-04 conformance scan descended into nested agent worktrees under
.claude/, counting 4 egress policies where 1 is authored.
Co-Authored-By: Claude Opus 5 <[email protected]>
Text-only cleanup after the upgrade campaign. Updates stale version
strings, prose, and comments to the verified current facts; no
Kubernetes behavior or version pins changed except the kubectl
toolchain bump (below).
Verified facts applied: k3s v1.36.4+k3s1, Debian 13 trixie,
Cilium 1.20.1 / Gateway API v1.6.1, Longhorn 1.12.1, node RAM 24 GiB,
dedicated virtio2 SSD etcd disk per node, Velero chart 12.x / v1.18,
Grafana 13.2.0.
- Version strings across infra/ and platform/ READMEs + comments
- kubectl toolchain 1.31.4 -> 1.36.4 (devcontainer/ci/conformance
versions.env; 1.31 vs a 1.36 cluster exceeded the +-1 skew)
- Retired-single-apps-Kustomization refs -> apps-wave-0/1/2 + apps-vms
with per-wave SOPS decryption (flux/clusters docs + bootstrap.sh)
- COMPLETED/historical banners on the three executed plan docs
- Resolved TODO(WS-SEC) markers -> Renovate-maintained ranges
- Appended dated DECISIONS-LOG entry (2026-08-30) superseding the
2026-08-26 LIVE STATE line
Left as revalidation items (not blind-edited): external-snapshotter
v8.2.0 vs 1.36, Cilium ext_authz/forward-auth relevance under 1.20.1,
conformance ImageVolume feature-gate assertions under 1.36.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
jakman85andClaude Opus 5