Service Tempo

5.2.53. Tempo

1. Overview

Tempo is Atlas' Grafana-native trace store, disabled by default. It uses local filesystem storage and has no Kong route.

Tempo has no built-in authentication layer, so Atlas keeps it internal-only and expects operators to inspect traces through Grafana.

2. Access

• SOURCE: TEMPO_SOURCE=disabled by default.
• Internal endpoint: http://tempo:3200.
• Direct host URL: none.
• Kong URL: none; no Kong route is generated.
• Grafana surface: the Tempo datasource is provisioned when Grafana starts.

3. Configuration

The service reads ./config/tempo.yaml, mounted to /etc/tempo/tempo.yaml. Atlas computes TEMPO_ENDPOINT from TEMPO_SOURCE. TEMPO_RETENTION_PERIOD sets trace retention (default 336h, Tempo's own 14-day default). Tempo 3 reads retention in its backend scheduler and its backend worker. The config sets both from this variable.

The image is distroless (no shell, no wget). The health check runs the binary's own /tempo -health, which probes /ready and exits nonzero until Tempo is ready. The Collector waits for this check to pass.

4. Architecture & Wiring

The OpenTelemetry Collector forwards traces to Tempo over OTLP HTTP. Grafana queries Tempo for trace exploration. This is a local development service, not a high-availability tracing deployment.

5. Capabilities & limitations

Support tier: experimental — Capability contract declared; no cited cold-start, workflow, or upgrade qualification run yet (evidence at v0.1.0).

Capability	Status	Verification	Notes
Local distributed trace storage	supported	tested	Atlas configures a filesystem-backed Tempo service receiving internal OTLP traces from the OpenTelemetry Collector and exposes it to Grafana.
Authenticated public trace ingestion	not-supported	tested	Tempo has no host port, Kong route, or authentication layer in the stock topology; ingestion is restricted to the backend network.
Highly available trace retention	not-supported	documented	The bundled single replica uses local filesystem storage and does not provide replicated object storage or production high availability.

6. Troubleshooting

• If ./start.sh stops with "OTel Collector requires Tempo", set TEMPO_SOURCE=container (or --tempo-source container), or disable the Collector.
• If Grafana cannot query traces, confirm TEMPO_ENDPOINT=http://tempo:3200 in the Grafana container environment.
• Roll back by setting TEMPO_SOURCE=disabled and OTEL_COLLECTOR_SOURCE=disabled.

7. Dependencies & Integrations

7.1. Current — Upstream (this service calls)

No upstream calls.

7.2. Current — Downstream (services that call this)

Service	Category
grafana	infra
otel-collector	infra

7.3. Architecture diagram

Open the full-size diagram for a full-screen view.

7.4. Future — Missing pair integrations

No high-confidence opportunities identified.

7.5. Future — Candidate new services

No high-confidence opportunities identified.

7.6. Future — Unused features in this service

No high-confidence opportunities identified.