What Are Traces and Spans in OpenTelemetry?
14 days ago
- #OpenTelemetry
- #Distributed Tracing
- #Node.js
- Distributed tracing in OpenTelemetry revolves around two core concepts: Trace (the full journey of a request across services) and Span (a timed unit of work within that journey).
- Spans contain metadata like name, start/end times, IDs, attributes, events, status, and links, which help in diagnosing performance issues and understanding request flows.
- Setting up tracing in Node.js involves installing OpenTelemetry packages, configuring exporters, samplers, and resources, and initializing telemetry before the application starts.
- Manual instrumentation allows for detailed tracing of specific operations, with utilities like `withSpan` to handle errors and context propagation automatically.
- Context propagation ensures trace continuity across asynchronous boundaries and network calls, using W3C trace headers for HTTP and messaging systems.
- Sampling strategies include head sampling (deciding at trace start) and tail sampling (deciding after seeing the full trace), balancing cost and observability.
- Best practices for span naming emphasize stability, low cardinality, and action-oriented names to maintain trace usability and searchability.
- Common anti-patterns include span explosion, high-cardinality names, logging everything as events, and mixing domains in a single span.
- Correlating traces with metrics and logs enhances observability, enabling comprehensive monitoring and troubleshooting of distributed systems.