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home-network-k3s-impl/clusters/prod/kustomization.yaml
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jakman85andClaude Opus 4.8 eb31d2ef58 fix(monitoring): cap Prometheus TSDB by size to stop false absent()/==0 alerts
The 7 falsely-firing platform alerts (KeycloakDown, KeycloakDatabaseDown,
KubeAPIDown, KubeletDown, VPNTunnelDown, KubeVirtControlPlaneDown,
CDINoDefaultStorageClass) share ONE root cause, not per-rule label mismatches:
the Prometheus PVC is 100% full ("no space left on device" on every WAL commit).

Evidence from the live dev cluster:
- /prometheus is 4.8G/5Gi, 0 bytes free; every scrape logs "Scrape commit
  failed ... write to WAL: no space left on device". Scrapes still return 200
  (targets show healthy, lastScrape=now) but samples are never stored, so the
  TSDB head froze at 2026-08-28 13:45 UTC while the pod clock reads ~19:33 UTC.
- Instant queries at "now" therefore return an EMPTY vector, so every
  absent()/==0 platform rule trips. Evaluated at the last-good-sample time each
  expr is correctly FALSE (keycloak-0/keycloak-db-1 ready=1, apiserver+kubelet
  up=1 x3, tun0 series present, kubevirt control-plane expr empty, CDI default
  present) — the rules are correct; the monitor was simply blind.

`retention` alone prunes only by AGE: this cluster is 3d2h old with 3d dev
retention, so time-pruning has NEVER run and 3d of block churn (~1.2Gi/day) plus
a WAL that ballooned past 1Gi overran the 5Gi disk. Fix adds a size-based
retention cap (new MONITORING_PROMETHEUS_RETENTION_SIZE knob) kept below each
env's PVC so Prometheus drops oldest blocks before the disk fills, and bumps the
dev PVC 5Gi->8Gi for real WAL/head/compaction headroom.

- platform/monitoring/kube-prometheus-stack.yaml: retentionSize: ${knob}
- clusters/base/cluster-vars.yaml: knob default 8GiB (base 10Gi PVC)
- clusters/dev/kustomization.yaml: PVC 5Gi->8Gi, retentionSize 5GiB
- clusters/prod/kustomization.yaml: retentionSize 45GiB (50Gi PVC)
- platform/monitoring/README.md: knob table + rationale

Deploy note (PM): the PVC is already 100% full, so Prometheus cannot self-prune
until it can write. The 5Gi->8Gi bump must land as a Longhorn online expansion
(operator PVC expansion / manual patch); once free space returns, retentionSize
keeps it healthy. Watchdog left untouched.

Co-Authored-By: Claude Opus 4.8 <[email protected]>
2026-08-28 14:38:12 -05:00

57 lines
2.3 KiB
YAML

---
# clusters/prod — DESIGN-ONLY overlay. NOT a build target until roadmap Phase 7 opens prod
# (spec roadmap/phases.md, AGENTS.md §6: "Never build directly on production").
#
# When Phase 7 is opened, `flux bootstrap ... --path=clusters/prod` points the prod cluster's Flux
# here. Like dev, this overlay adds NO resources — it ONLY patches cluster-vars with prod-scoped
# values (R-ENV-02). Promotion to prod is a change to THESE variables, never a base edit.
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- ../base
patches:
- target:
kind: ConfigMap
name: cluster-vars
patch: |-
- op: replace
path: /data/CLUSTER_ENV
value: "prod"
# trusted, rate-limited real certs in prod — ADR-0006.
- op: replace
path: /data/ACME_CLUSTER_ISSUER
value: "letsencrypt-prod"
- op: replace
path: /data/LONGHORN_DEFAULT_REPLICA_COUNT
value: "3"
# longer retention / larger volumes on prod NVMe.
- op: replace
path: /data/MONITORING_PROMETHEUS_RETENTION
value: "30d"
- op: replace
path: /data/MONITORING_PROMETHEUS_PVC_SIZE
value: "50Gi"
# Size-cap below the 50Gi PVC (headroom for WAL + head + compaction scratch): prod may hit the
# size cap before 30d if series volume is high, keeping the disk from filling either way.
- op: replace
path: /data/MONITORING_PROMETHEUS_RETENTION_SIZE
value: "45GiB"
- op: replace
path: /data/MONITORING_LOKI_PVC_SIZE
value: "50Gi"
# HA control-plane addons in prod.
- op: replace
path: /data/KEYCLOAK_REPLICAS
value: "2"
- op: replace
path: /data/OAUTH2_PROXY_REPLICAS
value: "2"
- op: replace
path: /data/VELERO_RETENTION
value: "720h"
# TODO(WS-INFRA, Phase 7): pin prod node placement once the bare-metal role labels exist.
# TODO(WS-NET, Phase 7): set GATEWAY_VIP to the prod LAN ingress VIP (add a `replace` op here)
# at the same time the prod Cilium LB IP pool range is supplied — the split-horizon
# coredns-custom (platform/coredns) answers *.home.keithjackson.dev with ${GATEWAY_VIP}, so
# the prod value must match the prod pool's Gateway address. Base default is the dev VIP.