Purpose

Write container logs to a known file for further processing.

Grafana Sample

Run docker-compose up -d in the sample folder to spin up a monitoring stack.

Grafana should now be available on http://localhost:3000 (use credentials admin:admin).

Navigate to the 'Explore' page using the menu on the left and you should be able to switch between the preconfigured Loki and Prometheus datasources. Click the metrics/log labels button next to the query field to explore the available data.

The stack contains the following building blocks:

• Grafana (http://localhost:3000): build dashboards and alerts using metrics and logs collected by Prometheus and Loki
• Prometheus (http://localhost:9090): time-series DB for metrics, scrapes /metrics endpoints to collect them
• node-exporter: provides host system metrics for prometheus
• Loki: Log DB
• Promtail: part of Loki, responsible for monitoring directories and sending Logs to Loki
• piper: this nodejs script, makes container logs available for promtail by piping them to files in a docker volume