observability

Logs, metrics, and traces form the three pillars of observability. Metrics provide quantitative system health data, traces track requests across distributed services, and logs offer discrete event records to diagnose root causes during incidents.

The RED and USE methods are frameworks for effective system monitoring. RED focuses on Rate, Errors, and Duration for request-driven services, while USE monitors Utilization, Saturation, and Errors for resource-based metrics to identify bottlenecks.

Distributed tracing tracks requests across services using spans and context propagation. Spans represent individual units of work, while context propagation links these spans together to visualize the complete request path through a distributed system.

Correlate logs, metrics, and traces by linking them through shared identifiers. Use metrics to detect error spikes, traces to pinpoint the failing request path, and structured logs with contextual fields to diagnose the root cause.

Structured logging best practices involve using consistent, machine-parseable formats with appropriate log levels and contextual fields. This standardization enables automated parsing and effective correlation with metrics and traces during debugging.

You need distributed tracing when debugging complex, distributed systems where requests span multiple services. It is essential for pinpointing performance bottlenecks and identifying the exact failing request path across service boundaries.