

- Traces: map the path of a request across distributed services to show where latency and errors occur.
- Metrics: surface aggregated performance trends and resource patterns over time.
- Logs: record detailed events and contextual information useful for debugging single requests.
- Collector: aggregates, processes, and exports telemetry consistently across environments.
Traces, metrics, and logs are most powerful when correlated: traces point to the problematic component, metrics reveal trends and scope, and logs provide the contextual details required to fix root causes.

| Signal / Component | Primary purpose | Best used for |
|---|---|---|
| Traces | Map request flows across services and measure latency per span | Root cause analysis of slow or failing requests |
| Metrics | Aggregate performance counters and resource usage over time | Detecting trends like CPU spikes or memory leaks |
| Logs | Detailed, per-event contextual information | Debugging specific errors or unexpected behavior |
| Collector | Centralized aggregation, processing, and exporting of telemetry | Consistent telemetry delivery across environments and vendors |
- A trace shows a downstream dependency timing out on certain spans.
- Metrics reveal a gradual increase in response time and memory utilization preceding the incidents.
- Logs include contextual errors and stack traces tied to the same request IDs found in traces.

- Instrument services for traces first to map request flows, then enrich with metrics and logs.
- Use a collector for consistent telemetry routing, sampling, and vendor-agnostic exports.
- Correlate signals by request IDs or span IDs to move from symptoms to root cause quickly.

- OpenTelemetry project: https://opentelemetry.io/
- Observability and incident response best practices: https://www.elastic.co/observability
- Distributed tracing concepts: https://kubernetes.io/docs/concepts/cluster-administration/logging/ (for related logging and tracing context)
Important: Telemetry is only useful if you collect the right signals and retain linkable identifiers (like trace IDs). Instrumentation gaps or inconsistent identifiers will create blind spots—even with a collector in place.