Loki

TAS Score: S3/3 — D4/5 · A3 / T2 (D4 not D5: Grafana Labs changed Loki’s license from Apache-2.0 to AGPL-3.0 in 2023 — trajectory signal.)

Brief Description

Log aggregation system by Grafana Labs. Designed to work alongside Prometheus — same labels, same query patterns. Indexes only metadata (labels), not log content — making it lightweight compared to Elasticsearch. Visualised through Grafana.

Architectural Role

Observability layer. Log storage and querying. Part of the PLG stack (Prometheus + Loki + Grafana). Promtail or Alloy collect logs from containers and systems and ship them to Loki.

Technical Autonomy

Works without internet
Stores data locally (filesystem or S3-compatible)
Does not require external accounts
Allows data export (LogQL queries, direct filesystem access)
Provides offline updates

Philosophical Assessment (whose.world criteria)

Criterion	Status	Comments
Pause	✅	Clean stop; no permanent damage
Exit	✅	Log chunks stored on filesystem; queryable directly
Recoverability	✅	Filesystem backup; stateless query layer
Visibility	✅	AGPL-3.0, fully auditable
External Dependencies	✅	Runs fully self-contained

Configuration (Minimal)

services:
  loki:
    image: grafana/loki:latest
    command: -config.file=/etc/loki/loki-config.yaml
    volumes:
      - ./loki-config.yaml:/etc/loki/loki-config.yaml
      - loki_data:/loki
    ports:
      - "3100:3100"

  promtail:
    image: grafana/promtail:latest
    command: -config.file=/etc/promtail/promtail-config.yaml
    volumes:
      - ./promtail-config.yaml:/etc/promtail/promtail-config.yaml
      - /var/log:/var/log:ro
      - /var/lib/docker/containers:/var/lib/docker/containers:ro

volumes:
  loki_data:

Alternatives

Alternative	Autonomy	Notes
Prometheus	A3 / T2	Metrics not logs — complementary, not alternative
Elasticsearch	A3 / T1	Full-text search, heavier, SSPL license (not OSI)

Trajectory

Direction: mixed

Loki was Apache-2.0 until 2023 when Grafana Labs changed it to AGPL-3.0 — the same move made for Grafana itself in 2021. The self-hosted version remains fully functional. Enterprise features (multi-tenancy at scale, SSO) are available in Grafana Cloud. Watch for further migration of features to the enterprise tier, consistent with the broader Grafana Labs pattern.

Signal assessment:

Signal	Status	Evidence
License	⚠️	Apache-2.0 → AGPL-3.0 in 2023; AGPL restricts embedding in proprietary products
Feature gating	➖	Core logging features remain open; enterprise = scale + SSO
Self-hosting	✅	Self-hosting well-supported; actively developed
Governance	➖	Grafana Labs controls direction; community contributions accepted

Sources

Website: https://grafana.com/oss/loki
Documentation: https://grafana.com/docs/loki/latest
Repository: https://github.com/grafana/loki
Docker image: grafana/loki
Community: https://github.com/grafana/loki/discussions