Logging & Observability interview question · Most asked
What is distributed tracing and how does OpenTelemetry fit in?
Summary
Distributed tracing records a request as a tree of timed spans across services; OpenTelemetry (OTel) is the vendor-neutral standard (APIs, SDKs, the OTLP protocol and the Collector) for producing and exporting traces, metrics and logs.
Longer Answer
Each span has a name, start/end time, attributes and a parent; context (trace ID, span ID) propagates between services via the W3C traceparent header. Auto-instrumentation libraries create spans for HTTP servers/clients, databases and queues without code changes, and you add custom spans for important business steps. The OTel Collector receives, processes (sampling, redaction) and exports data to backends like Jaeger, Tempo, Honeycomb or Datadog, so you can switch vendors without re-instrumenting.
Key Points
- Spans form a per-request tree
- W3C traceparent propagation
- Auto-instrumentation + custom spans
- Collector decouples apps from vendors
- Sampling controls cost
Explanation
What interviewers look for
Knowing context propagation and the role of the Collector, not just vendor names.
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