---
type: reference
description: "Alloy is Grafana's log and telemetry shipper."
tags:
  - infrastructure
timestamp: 2026-09-11
---

# Alloy

Alloy is Grafana's log and telemetry shipper. It replaces Promtail (EOL 2026-03-02). It forwards container and journal logs to Loki.

**Host:** Dankclaw (one instance per host) — **Port:** 12345 (loopback) — **Docs:** https://grafana.com/docs/alloy/latest

## Facts

| Item | Value |
|------|-------|
| Image | `franksdank/alloy:latest` (local build: upstream + a static busybox for the healthcheck) |
| Published | `127.0.0.1:12345` → 12345 (its own UI/health port) |
| Unit | `dankclaw/observability/quadlet/alloy.container` → `alloy.service` |
| Config | `shared/alloy/config.alloy`, installed to `/opt/alloy/config/` |
| Inputs | host journald socket, podman container logs, `/var/log` |
| Output | `http://loki:3100/loki/api/v1/push` |
| Successor to | Promtail (EOL 2026-03-02) |

## Why Alloy and not Promtail

Promtail reached end-of-life on 2026-03-02 and Grafana Labs directs new installs to Alloy. This stack uses Alloy from day one.

## Configuration

`shared/alloy/config.alloy` is the source of truth:

- Reads journald logs from the host's `/run/systemd/journal/socket`.
- Reads container logs from `/var/lib/containers/storage/...` (podman).
- Forwards to Loki with `job` labels.

## Volumes

| Container path | Host path |
|----------------|-----------|
| `/etc/alloy` | `/opt/alloy/config` |
| `/run/systemd/journal/socket` | host journald socket (read-only) |
| `/var/log` | host logs (read-only) |
| `/var/lib/containers` | podman storage (read-only) |

## The UI port is published on purpose

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.

## Gotchas

- The journald socket mount is required for journal scraping.
- 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.
- One Alloy per host; do not run a single instance that tries to reach both hosts' logs.
- The unit `Wants=`/`After=` `loki.service`: without a reachable Loki the write client fails and the pipeline backs up.

## See Also

- [[Loki]] — the log backend
- [[Observability]] — the full stack, including what is still unconfigured