OpenTelemetry tracing

One operation, many spans

A distributed trace is a tree of spans that follows one operation across services. Configure the Azure Monitor OpenTelemetry distro once and give each service a distinct service name so Application Map can separate them.

Add spans where libraries cannot

configure_azure_monitor()
tracer = trace.get_tracer(__name__)

with tracer.start_as_current_span("build-report") as span:
    ...

A custom span is a dependency by default. Use SpanKind.SERVER when background work should represent an incoming request.

Record handled failures

An exception that escapes a span can be captured automatically. If your code catches it and returns a fallback, call span.record_exception(ex) so the failure is still attached to the trace.

Know where telemetry lands

Incoming request spans appear in requests, outgoing calls in dependencies, and application logs in traces. The operation ID correlates telemetry that belongs to one end-to-end operation.

Control trace volume

Fixed-percentage sampling reduces stored traces, while metrics stay unsampled.