Four key metrics for monitoring distributed systems: latency, traffic, errors, and saturation. Like the vital signs doctors check to assess patient health.
SRE teams monitor the golden signals to quickly detect when a service is degraded - high latency or error rates trigger automatic alerts.
Golden Signals are a monitoring approach (latency, traffic, errors, saturation), not a single product. These cloud monitoring platforms can collect metrics/logs/traces and create dashboards and alerts for the four signals.