Tracing Overview

The OAP receives traces from three sources. Each is received, analyzed and stored its own way, and each has its own pages under this section.

	SkyWalking native traces	OpenTelemetry traces	Zipkin traces
Sent by	SkyWalking language agents, as trace segments	OpenTelemetry SDKs and collectors, over OTLP	Zipkin instrumentation and the service meshes that emit Zipkin spans
Received by	the trace receiver, receiver-trace, over gRPC and HTTP, or the Kafka fetcher	the OpenTelemetry receiver, receiver-otel	the Zipkin receiver, receiver-zipkin
Analyzed by	the sw-native TAL rules of trace-analyzer, listed in nativeTalFiles	the otlp TAL rules of trace-analyzer, listed in talFiles, for the services that set service.layer	not by TAL; the GenAI and AI evaluation span listeners read the spans
Modules	receiver-trace, agent-analyzer and trace-analyzer	receiver-otel; trace-analyzer for the analysis, agent-analyzer for the gateway list	receiver-zipkin, query-zipkin
Stored as	SkyWalking traces, one Segment record per sampled segment	SkyWalking traces or Zipkin traces, as otlpTraceStorage selects	Zipkin traces
Pages	Setup, Bundled analysis, TAL for native segments	Setup, Bundled analysis, TAL for OpenTelemetry spans, best practices	Zipkin traces

Beside TAL, the span listeners read OpenTelemetry spans too: the iOS ones, for iOS monitoring, and the GenAI ones. AI evaluation samples natively stored OpenTelemetry spans through the otlp-ai-evaluation TAL rule, and those stored as Zipkin spans, like Zipkin’s own, through its span listener.

Two configuration files serve more than one source:

• Uninstrumented gateways, gateways.yml, lists the gateways and proxies that do not trace; both TAL inputs ask it through isGateway, so a call through a listed gateway is drawn to the gateway.
• Server clusters, server-clusters.yml, renames the addresses of an uninstrumented server, a broker, a database or a cache to the cluster they belong to, for both TAL inputs.

Sampling and storage limits are per source: trace sampling for native traces, the receiver’s sample rate and rate limit for OpenTelemetry and for Zipkin, and BanyanDB’s trace tail sampling after storage.