Frank
701ab14f60
Rewrites the [[Observability]] umbrella page and the five component pages for what is actually deployed: rootless Quadlet units instead of compose services, the loopback-only publish posture (node-exporter's LAN binding explained), the loki healthcheck living in its image because the image has no shell, and the Home=/root trap that killed the first grafana start. Adds the note that matters most to a reader: the stack is installed, healthy and UNCONFIGURED. Grafana reports zero datasources and zero dashboards with an empty provisioning directory; Prometheus has no rule files and no Alertmanager; Loki is configured but has no reader; node-exporter runs its default collectors. Alloy is the only configured piece. Metrics and logs are collected and retained, and nothing is visualized or alerted on. AGENTS.md's boot-persistence gap note is replaced by the resolution.
60 lines
3.2 KiB
Markdown
60 lines
3.2 KiB
Markdown
# Prometheus
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Prometheus collects metrics from every service on Dankclaw by scraping their `/metrics` endpoints, and feeds Grafana once a datasource exists. node-exporter supplies host metrics from both machines.
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**Host:** Dankclaw — **Vhost:** `prometheus.franksdank.cloud` (guarded: Anubis →
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Authentik; post-auth the Caddy vhost routes straight to `prometheus:9090`) —
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**Port:** 9090 (loopback) — **Docs:** https://prometheus.io/docs
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## Facts
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| Item | Value |
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|------|-------|
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| Image | `docker.io/prom/prometheus:latest` |
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| Published | `127.0.0.1:9090` → 9090, loopback only (see [[Observability]] → Exposure) |
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| Unit | `dankclaw/observability/quadlet/prometheus.container` → `prometheus.service` |
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| Config | `/opt/prometheus/config/prometheus.yml`, installed from `shared/prometheus/prometheus.yml` on every deploy |
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| Data | `/opt/prometheus/data` (TSDB) |
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| Retention | `--storage.tsdb.retention.time=30d` |
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| Alerting | **none** — no rule files, no Alertmanager anywhere in the stack |
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## Targets
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`shared/prometheus/prometheus.yml` is the source of truth; the deploy copies it into the container's `/etc/prometheus/`. In outline:
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| Job | Target | Why |
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|-----|--------|-----|
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| `prometheus` | `localhost:9090` | itself |
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| `node-dankclaw`, `node-dankserver` | `192.168.0.143:9100`, `192.168.0.235:9100` | host metrics from each machine's [[Node-Exporter]] |
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| `gitea` | `192.168.0.143:3000` | Gitea's built-in exporter, reached on its published LAN port |
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| `grafana`, `loki` | `grafana:3000`, `loki:3100` | container names on the `dankclaw_default` network |
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| `comfyui` | `comfyui:8188` | UI probe; ComfyUI has no native `/metrics` |
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| `services` | `192.168.0.143:8081`, `:3005` | up/down probes for SearXNG and OpenWebUI |
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Targets are `host:port`, never URLs. For richer HTTP assertions, add the Prometheus **blackbox** exporter in probe mode rather than scraping HTML.
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## Volumes
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| Container path | Host path |
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|----------------|-----------|
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| `/etc/prometheus` | `/opt/prometheus/config` |
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| `/prometheus` | `/opt/prometheus/data` |
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## Healthcheck
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Prometheus responds on `/-/healthy` with 200; the unit's health command is the same `wget --spider` the deploy waits on.
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## Gotchas
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- **Keep the node-exporter address in step with the unit.** `node-dankclaw` scrapes `192.168.0.143:9100`, which is exactly the LAN address `node-exporter.container` binds (`Network=host`, `--web.listen-address` twice). Change one without the other and host metrics stop with no error anywhere. The `tests/observability_quadlet.bats` seam pins the pairing.
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- The container name `prometheus` is what Caddy's post-auth handler proxies to, and `grafana`/`loki` are addressed by name here. Renaming a container breaks both silently.
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- Keep scrapes modest for a small homelab; too many targets bloat the TSDB.
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- Set a retention policy or the data volume grows without bound (30 days here).
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- The lifecycle endpoint is enabled (`--web.enable-lifecycle`), which is why this API must never be published beyond loopback.
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## See Also
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- [[Grafana]] — the dashboard frontend (no datasource configured yet)
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- [[Node-Exporter]] — the host metrics source
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- [[Observability]] — the whole stack, including what is still unconfigured
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