Opentelemetry Tracing

OpenTelemetry & Distributed Tracing

Core Concepts

OpenTelemetry (OTel) is an open standard for generating, collecting, and exporting telemetry data (Metrics, Logs, and Traces).

1. Distributed Tracing

In a microservices architecture, a single user request might hit 10 different services. Tracing visualizes this entire journey.

• Trace ID: A unique identifier for the entire transaction.
• Span ID: Represents a single unit of work (e.g., a DB query, an HTTP call) within the trace.
• Context Propagation: Services must extract the Trace ID from incoming HTTP Headers (e.g., traceparent W3C standard) and inject it into outgoing requests.

2. OTel Collector

Instead of services sending data directly to vendors (Datadog/Jaeger), they send it to the OTel Collector. The Collector acts as a vendor-agnostic pipeline (Receive -> Process -> Export).

Distributed Tracing Map

%%{init: {"theme": "default", "flowchart": {"useMaxWidth": true}}}%%
flowchart TD
    subgraph Microservices ["Service Mesh"]
        A["Frontend Service<br/>(Generates Trace ID)"]
        B["Auth Service<br/>(Child Span)"]
        C["Order Service<br/>(Child Span)"]
    end
    
    subgraph Telemetry ["OTel Infrastructure"]
        D["OTel Collector (Agent/Gateway)"]
        E["Process (Batch/Filter)"]
        F["Export (Jaeger/Datadog)"]
    end
    
    A -->|"HTTP + traceparent Header"| B
    A -->|"HTTP + traceparent Header"| C
    
    A -.->|"Send Spans (OTLP)"| D
    B -.->|"Send Spans (OTLP)"| D
    C -.->|"Send Spans (OTLP)"| D
    
    D --> E
    E --> F