I treat observability as a way of understanding system behaviour, not as collecting logs "just in case". I combine metrics, logs and tracing so that it is quick to answer not only whether the system works, but above all why it is working badly.
Prometheus, Grafana, OpenTelemetry, Loki, ELK, Sentry, Metrics, Logs, Tracing, Alerting, Dashboards, SLI, SLO, Incident Analysis