Loki

Loki is a log aggregation system that indexes labels rather than the full text of a log line, so it stores and queries logs cheaply and stays closely aligned with the metric labels used by Prometheus. Agents such as Grafana Alloy, Promtail, or the OpenTelemetry Collector ship container and system logs to it, and LogQL queries then slice them by service, environment, and other labels in Grafana.

Teams use it to correlate log lines with metrics and traces across a whole platform.

Deploying it on your own infrastructure keeps operational logs, which often contain user or request data, under your own storage, avoids ingestion based pricing, and makes the index and chunk files part of your normal backup plan.