ef62dde67c
Turns the four monitoring backup CronJobs' .prom output into scrapeable
Prometheus series so the DEV-490 alerts finally evaluate against live data.
- apps/observability/patches/node-exporter-textfile-collector.yaml:
strategic-merge patch on the kube-prometheus-stack node-exporter DS
that adds `--collector.textfile.directory=/host/textfile_collector`
and mounts `/var/lib/node_exporter/textfile_collector` read-only.
Chart isn't tracked in ArgoCD, so we keep the patch under version
control and re-apply after any helm upgrade (see patches/README.md).
- apps/monitoring/backup-{loki,grafana,k8s-resources,prometheus}-*-cronjob.yaml:
swap `emptyDir` /metrics for a `hostPath` on the same directory
(`DirectoryOrCreate`). Write via `.prom.tmp` + `mv` so node-exporter
never reads a truncated sample.
- apps/monitoring/backup-restic-alerts.yaml: `time() - max(...) > 28h`
for all four freshness alerts so a stale `.prom` left on a node the
job has since left does not fire the freshness pager.
- apps/monitoring/README.md: drop the "once wired" caveat; document
the on-node directory, atomic write, cross-node staleness rationale.
Verified end-to-end with a synthetic `kubectl create job
--from=cronjob/backup-k8s-resources`: pod ran on k3s-worker-4,
.prom file materialized in /var/lib/node_exporter/textfile_collector,
and Prometheus returned all four metric families
(`backup_k8s_resources_success=1`, `..._timestamp_seconds`,
`..._check_status=0`, `restic_repo_size_bytes{repo="k8s-resources"}=13692516`).
`time() - max(backup_k8s_resources_timestamp_seconds)` returned ~84s
against a fresh run. `promtool check rules` + `promtool test rules`
still pass (9 rules, 5 scenarios).
Co-Authored-By: Paperclip <noreply@paperclip.ing>
58 lines
7.9 KiB
Markdown
58 lines
7.9 KiB
Markdown
# monitoring — backup CronJobs
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Manifests recording the cluster-side monitoring backup CronJobs that were previously applied out-of-band. These files are the authoritative source (`kubectl apply -f apps/monitoring/`). See [DEV-464](/DEV/issues/DEV-464) for the repair context.
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- `backup-k8s-resources-cronjob.yaml` — daily dump of cluster-scoped and per-namespace Kubernetes resources, streamed through `restic backup --stdin` to `hetzner-s3:${BUCKET}/restic/k8s-resources`. Uses `serviceAccountName: backup-sa` and no PVC mount (init container `alpine/k8s:1.29.4` writes an emptyDir, main container `restic/restic:0.17.3` reads it on stdin). Rewritten from the local-path tarball per the [DEV-482](/DEV/issues/DEV-482) Option 4 rollout ([DEV-487](/DEV/issues/DEV-487)).
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- `backup-loki-restic-cronjob.yaml` — daily restic backup of `loki-storage-encrypted` to `hetzner-s3:${BUCKET}/restic/loki`. Co-schedules with the Loki pod via `podAffinity` (RWO permits additional read-only mounts on the same node). Deployed per the [DEV-482](/DEV/issues/DEV-482) Option 4 rollout ([DEV-485](/DEV/issues/DEV-485)).
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- `backup-grafana-restic-cronjob.yaml` — daily restic backup of `grafana-storage` to `hetzner-s3:${BUCKET}/restic/grafana`. Pinned to `k3s-worker-2` via `nodeSelector` (the local-path PV anchors the grafana pod there already, no `podAffinity` needed). Schedule `15 3 * * *` — offset from the loki run at `03:00`. Deployed per the [DEV-482](/DEV/issues/DEV-482) Option 4 rollout ([DEV-486](/DEV/issues/DEV-486)).
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- `prometheus-backup-cronjob.yaml` + `prometheus-backup-sealed.yaml` — daily restic backup of `prometheus-data-encrypted` to `hetzner-s3:${BUCKET}/restic/prometheus`. Co-schedules with the Prometheus pod via `podAffinity` so the RWO PVC attaches on the same node. Schedule `30 3 * * *` — offset from the loki (03:00) and grafana (03:15) runs. Migrated from the DEV-465 `rclone sync` job to restic client-side encryption per [DEV-492](/DEV/issues/DEV-492) / [DEV-482](/DEV/issues/DEV-482) Option 4. **Compaction-race mitigation:** `--exclude wal/*` + `--exclude chunks_head/*` + accept `restic backup` exit code 3 (source file vanished mid-walk) as a warning, not a failure; restore drill re-runs `promtool tsdb analyze` per block.
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- `backup-restic-alerts.yaml` + `backup-restic-alerts.test.yaml` — `PrometheusRule` with freshness, integrity, and repo-size alerts covering the four restic repos (loki/grafana/k8s-resources/prometheus), plus a `promtool test rules` unit test proving each alert fires against synthetic samples ([DEV-490](/DEV/issues/DEV-490), extended in [DEV-492](/DEV/issues/DEV-492)).
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## Shared SealedSecret
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All four restic CronJobs read Hetzner S3 credentials + the restic repository password from **SealedSecret `monitoring-s3-backup`** (namespace `monitoring`). Keys:
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| Key | Purpose |
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|------------------|------------------------------------------------------------------------------------------------------------------|
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| `access-key` | Hetzner Object Storage access key ID |
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| `secret-key` | Hetzner Object Storage secret access key |
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| `endpoint` | S3 endpoint hostname (e.g. `fsn1.your-objectstorage.com`) |
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| `bucket` | Bucket name (single bucket, per-prefix repos) |
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| `restic-password`| 32-byte random string sealed at [DEV-484](/DEV/issues/DEV-484); plaintext copy in Passbolt entry `restic / monitoring backups`. Rotation: `restic key add` → seal new value → `restic key remove` old id. Same key protects all four repos (loki/grafana/k8s-resources/prometheus) — rotating rewrites the key file on every repo. |
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## Restore
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Restore procedure for all three restic repos: [`docs/monitoring/restic-restore.md`](../../docs/monitoring/restic-restore.md). First drill (2026-08-16) passed — see [DEV-488](/DEV/issues/DEV-488).
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## Emitted metrics (textfile-collector format)
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Each restic CronJob writes `/metrics/backup_<kind>.prom` (atomic — `.prom.tmp` + `mv`) into a `hostPath` volume mounted at the node-exporter textfile-collector directory (`/var/lib/node_exporter/textfile_collector`). The kube-prometheus-stack node-exporter DaemonSet has `--collector.textfile.directory=/host/textfile_collector` enabled ([DEV-494](/DEV/issues/DEV-494), applied via [`apps/observability/patches/node-exporter-textfile-collector.yaml`](../observability/patches/node-exporter-textfile-collector.yaml)) and surfaces those samples in Prometheus.
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| Metric | Emitted by |
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|--------------------------------------------|----------------------------------------------------------------------------------|
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| `backup_<kind>_success` (0/1) | `backup-{loki,grafana,k8s-resources}-*-cronjob.yaml`, `prometheus-backup-cronjob.yaml` |
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| `backup_<kind>_timestamp_seconds` | same |
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| `backup_<kind>_check_status` (exit code) | same — from `restic check --read-data-subset=5%` |
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| `backup_prometheus_backup_status` | `prometheus-backup-cronjob.yaml` — `restic backup` exit code (3 = accepted compaction race) |
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| `restic_repo_size_bytes{repo="<kind>"}` | same — from `restic stats --json --mode raw-data` (added in DEV-490) |
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**Cross-node staleness note.** Because a backup CronJob may run on a different worker across days (loki/prometheus follow their app pods, `k8s-resources` is unpinned), a `.prom` file can linger on a node the job has since left and node-exporter keeps exposing it. The freshness alerts collapse the per-node samples with `max()` so the freshest sample wins; check/size alerts fire when *any* node reports a bad value, which is intentional — a recent failure is still a signal until the file is manually cleaned or the job returns to that node.
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## Alerts
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`backup-restic-alerts.yaml` defines nine alerts (all `severity: warning`):
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- `BackupLokiStale` / `BackupGrafanaStale` / `BackupK8sResourcesStale` / `BackupPrometheusStale` — `time() - max(backup_<kind>_timestamp_seconds) > 28h`. Daily schedule + 4 h grace. `max()` collapses per-node samples so a stale `.prom` on a node the job has left does not fire.
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- `BackupLokiCheckFailed` / `BackupGrafanaCheckFailed` / `BackupK8sResourcesCheckFailed` / `BackupPrometheusCheckFailed` — `backup_<kind>_check_status != 0`.
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- `ResticRepoOversize` — `restic_repo_size_bytes > 20 GiB`. Baseline expected < 5 GiB; catches retention/prune regressions.
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All alerts carry a `Runbook: docs/monitoring/restic-restore.md` annotation. To iterate on the rule file locally:
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```bash
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awk '/^spec:/{f=1;next} f{sub(/^ /,"");print}' \
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apps/monitoring/backup-restic-alerts.yaml > /tmp/backup-restic-rules.yaml
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promtool check rules /tmp/backup-restic-rules.yaml
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promtool test rules apps/monitoring/backup-restic-alerts.test.yaml
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```
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The legacy `backup-volumes` CronJob and its 100 Gi local-path `backup-storage` PVC were retired in [DEV-489](/DEV/issues/DEV-489) once the restic pipeline was proven end-to-end. With the shared destination PVC gone, the DEV-483 bridge `nodeSelector` pinning Loki to `k3s-worker-2` was also removed — `backup-loki-restic` follows the Loki pod via `podAffinity` regardless of which node the RWO CSI volume lands on. `backup-grafana-restic` still nodeSelects `k3s-worker-2` because its source PV (`grafana-storage`, local-path) is anchored there. `backup-k8s-resources` has no PVC dep and stays unpinned. `prometheus-backup` uses `podAffinity` on `app=prometheus` (RWO PVC on Hetzner CSI, single-node attach) and follows the Prometheus pod between workers.
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