jakman85andClaude Opus 5
7057bbb711
VeleroNoRecentBackup could not fire for the failure mode that actually happened.
`(time() - velero_backup_last_successful_timestamp{schedule!=""}) > 24*3600` is the
right SHAPE — per-schedule, un-aggregated — but Velero only creates that series once
a backup for the schedule SUCCEEDS, and `time() - <absent series>` yields no series.
So it detects "backed up once, then stopped" and is structurally INERT on "never
backed up". Prod ran with `velero-daily` (the schedule carrying VOLUME DATA) paused
and never-successful: no volume backups at all, nothing alerted, and it was masked
because `velero-daily-resources-only` completed cleanly every 03:00, so every other
backup signal read green while only Kubernetes objects were protected.
A PromQL-only fix is impossible, verified rather than assumed: velero v1.18.1 exports
35 velero_* metric names and every one carrying a `schedule` label is created by a
backup ATTEMPT, not by the Schedule object. A throwaway `paused: true` Schedule on
prod produced ZERO velero_* series, and nothing exposes `spec.paused`. The fact is
not in the TSDB, so the Schedule CRs are exported via kube-state-metrics'
custom-resource-state collector — the path this repo already uses for
kube_node_labels — as kube_velero_schedule_{created,paused,protects_volume_data,info}.
Proven by running KSM v2.20.0 with this exact config against prod's API: the CRD
list/watch rule the chart adds is MANDATORY, not cosmetic — without it KSM emits the
CRS metrics as an empty set, silently.
Three rules, all keyed on PROPERTIES rather than schedule names:
* VeleroScheduleNeverBackedUp (critical) — a Schedule older than 36h with no
successful backup ever. The 36h grace comes from creationTimestamp so a newly
added schedule is not paged before its first run is even due.
* VeleroSchedulePaused (warning) — the direct root-cause signal; a paused backup
schedule must never be silently indefinite.
* VeleroNoVolumeDataBackup (critical) — THE ANTI-MASKING RULE. Fires unless some
schedule with spec.template.defaultVolumesToFsBackup=true succeeded in 36h, so a
healthy resources-only schedule can never make the platform look protected.
Reading the property that DEFINES volume protection (not a name list) matches
platform/velero/volume-policies.yaml and survives renames. `or vector(0)` is
load-bearing: `count(<empty>) == 0` returns no series and would be inert —
absence of the exporter is deliberately the alarm.
Adds the repo's first Prometheus rule-unit-test harness (platform/monitoring/tests/,
wired as the `prom-rules` gate stage). It flattens the COMMITTED PrometheusRule CRs —
never a copy — and pins every rule in the group both ways: quiet on today's healthy
prod state, firing on the reconstructed bad state, with `for:` durations asserted.
Two mutation checks confirm the tests are not vacuous: dropping `or vector(0)` and
breaking the `unless on (schedule)` join each turn the suite red. This is the tool
that makes both of this repo's recurring alert bugs — permanently-firing and
structurally inert — provable offline, which neither yamllint, Kyverno, nor a healthy
cluster can do.
Proof of the fix is by construction; the live metrics cannot show it any more, because
`velero-daily` was unpaused on 2026-09-12 and has since completed 2492/2492 items.
The throwaway probe Schedule and the probe KSM deployment were deleted and the
deletion confirmed; `velero-daily` remains unpaused.
Co-Authored-By: Claude Opus 5 <[email protected]>
6.5 KiB
6.5 KiB
platform/monitoring
Observability stack — kube-prometheus-stack (Prometheus + Alertmanager + Grafana) + Loki + Grafana Alloy + platform-health PrometheusRules.
- Spec: docs/10 — Observability & Alerting (named in docs/01; no dedicated ADR)
- Serves: R-OBS-01/02/03/04 (supports R-C2-02, R-SEC-03, R-STATE-03)
- Owner: WS-OBS
Contents
| File | What |
|---|---|
namespace.yaml |
monitoring namespace |
helmrepositories.yaml |
prometheus-community + grafana Flux HelmRepositorys |
kube-prometheus-stack.yaml |
HelmRelease — Prometheus, Alertmanager (→ SMTP email), Grafana, kube-state-metrics, node-exporter |
loki.yaml |
HelmRelease — Loki single-binary, filesystem, compactor-enforced retention |
alloy.yaml |
HelmRelease — Grafana Alloy DaemonSet, tails pod logs → Loki |
alerts.yaml |
Platform-health PrometheusRules (R-OBS-04) |
tests/ |
promtool test rules unit tests over the committed PrometheusRules — each rule pinned quiet on the good state and firing on the bad one (tests/run.sh, or make -C ci prom-rules) |
kustomization.yaml |
builds all of the above |
Requirement mapping
- R-OBS-01 (what is monitored): Prometheus + node-exporter + kube-state-metrics for metrics;
Alloy → Loki for logs.
serviceMonitorSelectorNilUsesHelmValues: falseso ServiceMonitors from every namespace (and those rendered from ServiceDefinitions, docs/13) are scraped by default. - R-OBS-02 (alert delivery): Alertmanager routes by
severity(criticalvswarning) to email. SMTP creds are a SOPS secret referenced by name only (see below). - R-OBS-03 (dashboards): Grafana, with the dashboard/datasource sidecar watching
grafana_dashboard-labeled ConfigMaps across all namespaces (per-service dashboards land here). Grafana is part of the C2 UI composition (docs/12), later behind Keycloak SSO (ADR-0014). - R-OBS-04 (platform health):
alerts.yaml— first-class alerts for nodes, Longhorn, Flux, cert-manager, networking/VPN/Hubble, Velero backups, Keycloak/IdP, and the monitor's own capacity. Splitcritical/warningper the docs/10 severity model.
SMTP secret (operator hand-off)
Alertmanager reads the SMTP password from a mounted SOPS-encrypted Secret — referenced by name, never inlined. The operator must provide (out of band, SOPS-encrypted per docs/07):
kind: Secret
metadata:
name: alertmanager-smtp # <-- referenced in kube-prometheus-stack.yaml (alertmanagerSpec.secrets)
namespace: monitoring
stringData:
smtp-password: "<app password>" # mounted at /etc/alertmanager/secrets/alertmanager-smtp/smtp-password
The non-secret SMTP fields (smtp_smarthost, smtp_from, smtp_auth_username, and the
receiver to: address) are REPLACE-ME placeholders in kube-prometheus-stack.yaml for the
operator to fill (same convention as velero/). Grafana's admin bootstrap likewise references a
SOPS secret by name — grafana-admin-credentials (keys admin-user / admin-password).
Dev trims (the ~22 GiB RAM ceiling)
This subtree is authored to stay light on the single dev workstation:
- Loki
chunksCache/resultsCacheDISABLED — the grafana/loki chart's default memcached caches request ~8-9 GiB each; leaving them on would blow the budget by itself. Also disabled: the nginxgateway,lokiCanary, andtesthooks. Loki runs SingleBinary (one pod). - Single replicas everywhere (Prometheus, Alertmanager, Grafana, Loki).
- Modest requests/limits on every component (see values). Ephemeral (emptyDir) state for Alertmanager and Grafana in dev.
- k3s control-plane scrape jobs disabled (
kubeControllerManager/kubeScheduler/kubeEtcd/kubeProxy) — embedded in k3s, not separately scrapable; keeps targets green and RAM down.
Approximate steady-state memory requests (what the scheduler reserves):
| Component | Req | Notes |
|---|---|---|
| Prometheus | 384Mi | limit 1Gi |
| Alertmanager | 32Mi | |
| Grafana | 128Mi | |
| prometheus-operator | 96Mi | |
| kube-state-metrics | 64Mi | |
| node-exporter ×3 | 96Mi | 32Mi/node DaemonSet |
| Loki (single binary) | 192Mi | limit 512Mi |
| Alloy ×3 | 288Mi | 96Mi/node DaemonSet |
| Total requests | ~1.3 GiB | working set typically ~1.5-2.5 GiB; limit ceiling ~3 GiB |
Comfortably within the 22 GiB box alongside the rest of the platform.
Environment knobs (R-ENV-02)
Only three substitution vars touch this subtree; the dev overlay (clusters/dev) patches
cluster-vars to dev values:
| Var | base | dev |
|---|---|---|
${MONITORING_PROMETHEUS_RETENTION} |
7d |
3d |
${MONITORING_PROMETHEUS_PVC_SIZE} |
10Gi |
8Gi |
${MONITORING_PROMETHEUS_RETENTION_SIZE} |
8GiB |
5GiB |
${MONITORING_LOKI_PVC_SIZE} |
10Gi |
5Gi |
MONITORING_PROMETHEUS_RETENTION_SIZE is a size-based retention cap (Prometheus *iB units,
distinct from the K8s Gi PVC knob) and must stay below MONITORING_PROMETHEUS_PVC_SIZE. Time-only
retention prunes nothing until the age window elapses, so a young/busy cluster fills /prometheus first;
a full disk wedges every WAL commit (scrapes still 200 but samples are dropped, the head freezes) and
makes every absent()/==0 platform alert fire falsely. The size cap drops the oldest blocks before the
disk fills. (prod overlay: PVC 50Gi, cap 45GiB.)
PVCs use the replicated longhorn StorageClass (ADR-0003).
Notes / known gaps for bring-up
- Loki log retention has no dedicated knob. Only the three vars above exist. Loki's
retention_periodis hardcoded to72h(compactor-enforced) to mirror dev metrics retention. Promote to acluster-varsknob (inclusters/, out of this subtree) if per-env log retention is wanted. - Several R-OBS-04 rules depend on exporters/ServiceMonitors owned by other workstreams (Flux,
cert-manager, Longhorn, Velero, Keycloak, Cilium/Hubble). Rules are authored to fire once those
series arrive; metric names marked
TODO(WS-*)inalerts.yaml(notably the egress VPN metric) need confirming against the deployed exporter. - Hubble network-flow visibility itself is delivered by
platform/cilium(docs/03); this subtree only consumes its metrics for denied-flow alerts.
Validate (no deploy)
kubectl kustomize platform/monitoring
Author-only — nothing here is applied to a cluster; Flux reconciles it at deploy time.