---
type: reference
description: "Loki is the log aggregation backend of the observability stack."
tags:
  - infrastructure
  - loki
timestamp: 2026-09-11
---

# Loki

Loki is the log aggregation backend of the observability stack. It stores and queries container and system logs. It replaces the need for a full ELK stack.

**Host:** Dankclaw — **Port:** 3100 (loopback) — **Docs:** https://grafana.com/docs/loki/latest

## Facts

| Item | Value |
|------|-------|
| Image | `franksdank/loki:latest` (local build: upstream + a static busybox for the healthcheck) |
| Published | `127.0.0.1:3100` → 3100, loopback only |
| Unit | `dankclaw/observability/quadlet/loki.container` → `loki.service` |
| Mode | single-binary (all components in one process) |
| Storage | filesystem, `/opt/loki/data` |
| Auth | `auth_enabled: false` (single-tenant homelab) |
| Schema | v13 / TSDB |
| Retention | 30 days, enforced by the compactor |

## Configuration

`shared/loki/loki-config.yaml` is the source of truth, installed to `/opt/loki/config/loki-config.yaml` on every deploy. Key settings:

- `schema_config` v13 with `store: tsdb` and a filesystem object store.
- `compactor` with `retention_enabled: true` so logs do not grow without bound.
- `replication_factor: 1` for a single instance.

## Volumes

| Container path | Host path |
|----------------|-----------|
| `/loki` | `/opt/loki/data` |
| `/etc/loki` | `/opt/loki/config` |

## Healthcheck

Loki responds on `/ready` with 200. The health command is **not** in the unit: a unit `HealthCmd` reaches podman as `CMD-SHELL`, i.e. `/bin/sh -c`, and this image is distroless with no shell at all. It ships in `dankclaw/loki/Containerfile` as an exec-form `HEALTHCHECK` instead (which is why the image carries busybox, and why the build must pass `--format docker` — the OCI image format has no `HEALTHCHECK` field and silently drops it).

## Log Shipping

The [[Alloy]] agent on Dankclaw ships container and journal logs to `http://loki:3100/loki/api/v1/push` — by container name on the `dankclaw_default` network, never through the vhost (a non-browser client cannot solve the Anubis challenge).

## Gotchas

- Filesystem storage grows; keep compactor retention on.
- Loki and Alloy must agree on the push URL: `http://loki:3100/loki/api/v1/push`.
- The listener is loopback-only now. Shipping logs from a second host would need the unit's publish changed (or a shared network), not just an Alloy install — Loki has no authentication of its own, so that decision is a security one, not a config one.
- Nothing queries Loki yet: Grafana has no datasource configured. See the state note in [[Observability]].

## See Also

- [[Alloy]] — the log shipper
- [[Grafana]] — the query frontend
- [[Observability]] — the whole stack