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.
55 lines
2.7 KiB
Markdown
55 lines
2.7 KiB
Markdown
# Alloy
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Alloy is Grafana's log and telemetry shipper. It replaces Promtail (EOL 2026-03-02). It forwards container and journal logs to Loki.
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**Host:** Dankclaw (one instance per host) — **Port:** 12345 (loopback) — **Docs:** https://grafana.com/docs/alloy/latest
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## Facts
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| Item | Value |
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|------|-------|
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| Image | `franksdank/alloy:latest` (local build: upstream + a static busybox for the healthcheck) |
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| Published | `127.0.0.1:12345` → 12345 (its own UI/health port) |
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| Unit | `dankclaw/observability/quadlet/alloy.container` → `alloy.service` |
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| Config | `shared/alloy/config.alloy`, installed to `/opt/alloy/config/` |
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| Inputs | host journald socket, podman container logs, `/var/log` |
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| Output | `http://loki:3100/loki/api/v1/push` |
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| Successor to | Promtail (EOL 2026-03-02) |
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## Why Alloy and not Promtail
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Promtail reached end-of-life on 2026-03-02 and Grafana Labs directs new installs to Alloy. This stack uses Alloy from day one.
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## Configuration
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`shared/alloy/config.alloy` is the source of truth:
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- Reads journald logs from the host's `/run/systemd/journal/socket`.
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- Reads container logs from `/var/lib/containers/storage/...` (podman).
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- Forwards to Loki with `job` labels.
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## Volumes
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| Container path | Host path |
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|----------------|-----------|
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| `/etc/alloy` | `/opt/alloy/config` |
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| `/run/systemd/journal/socket` | host journald socket (read-only) |
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| `/var/log` | host logs (read-only) |
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| `/var/lib/containers` | podman storage (read-only) |
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## The UI port is published on purpose
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Alloy's UI listens on the container's own `127.0.0.1:12345` by default, and Alloy 1.x refuses to configure the `ui` service from a config block ("service ui does not support being configured"). Under compose that meant **no reachable health endpoint at all**: the homepage status card for alloy read `down` continuously and a deploy had nothing to wait on. The unit therefore passes `--server.http.listen-addr=0.0.0.0:12345` and publishes `127.0.0.1:12345` — same posture as the other three: reachable from the host and from Caddy's network, and from nothing off-host. Alloy has no authentication, which is exactly why it is not published wider.
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## Gotchas
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- The journald socket mount is required for journal scraping.
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- Container log paths differ between docker (`/var/lib/docker/containers`) and podman (`/var/lib/containers/storage/...`); point the config at the right one per host.
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- One Alloy per host; do not run a single instance that tries to reach both hosts' logs.
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- The unit `Wants=`/`After=` `loki.service`: without a reachable Loki the write client fails and the pipeline backs up.
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## See Also
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- [[Loki]] — the log backend
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- [[Observability]] — the full stack, including what is still unconfigured
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