docker-compose

name	docker-compose
description	Manage the local observability stack via Docker Compose. Use when: starting, stopping, or restarting services (Grafana, Tempo, Loki, OTel Collector), troubleshooting connectivity, checking service logs, or verifying the stack is healthy.

Docker Compose — Observability Stack

When to Use

• Starting or restarting the observability stack
• Troubleshooting service connectivity or missing data
• Checking logs of any service
• Verifying the stack is healthy after configuration changes

Stack Overview

Service	Image	Ports	Config File
otel-collector	otel/opentelemetry-collector-contrib:0.123.0	4317 (gRPC), 4318 (HTTP), 8888 (metrics)	observability/otel-collector/config.yaml
tempo	grafana/tempo:2.7.2	3200	observability/tempo/tempo.yaml
loki	grafana/loki:3.5.0	3100	observability/loki/loki.yaml
grafana	grafana/grafana:11.6.0	3000	observability/grafana/datasources/datasources.yaml

Config file: docker-compose.yml (project root)

Data Flow

Android App (OTLP/HTTP :4318)
  → OTel Collector
    → Tempo (:4317 gRPC) for traces
    → Loki (:3100 OTLP/HTTP) for logs
  → Grafana reads from Tempo + Loki

Common Commands

Start the full stack

docker compose up -d

Stop the full stack

docker compose down

Restart a single service (e.g., after dashboard/config changes)

docker compose restart grafana
docker compose restart otel-collector

View logs

docker compose logs -f otel-collector    # follow collector logs
docker compose logs tempo --tail=50      # last 50 Tempo lines
docker compose logs loki --tail=50       # last 50 Loki lines

Check service health

docker compose ps                                    # all services status
curl -s http://localhost:3200/ready                   # Tempo readiness
curl -s http://localhost:3100/ready                   # Loki readiness
curl -s http://localhost:8888/metrics | head -5       # Collector self-metrics

When to Restart What

Change	Command
Dashboard JSON edited	docker compose restart grafana
Datasource YAML edited	docker compose restart grafana
Collector config edited	docker compose restart otel-collector
Tempo config edited	docker compose restart tempo
Loki config edited	docker compose restart loki
All configs changed	docker compose down && docker compose up -d

Android App Connection

• Emulator: App sends to http://10.0.2.2:4318/v1/traces (Android emulator alias for host machine's localhost)
• Physical device: Update the endpoint in MainApplication.kt to your LAN IP (e.g., http://192.168.1.X:4318)

Troubleshooting

No traces in Grafana

1. Check Collector is receiving data: docker compose logs -f otel-collector — look for span export logs
2. Check Tempo is up: curl http://localhost:3200/ready
3. Verify the app endpoint points to the Collector

No logs in Grafana

1. Check Collector logs pipeline: docker compose logs otel-collector | grep -i log
2. Check Loki is up: curl http://localhost:3100/ready
3. Verify Loki receives OTLP: curl -s "http://localhost:3100/loki/api/v1/query" --data-urlencode 'query={service_name="com.paligot.otel-demo"}' | python3 -m json.tool | head -10

Grafana shows "No data"

1. Check the time range (default: last 1h) — the app must have been running recently
2. Verify datasource connectivity: Grafana → Connections → Data sources → Test
3. Restart Grafana: docker compose restart grafana

Volumes

Three named volumes persist data across restarts:

• tempo-data — trace blocks and WAL
• loki-data — log chunks and index
• grafana-data — Grafana state (user prefs, annotations)

To fully reset: docker compose down -v (destroys all stored data)