Distributed Tracing — Detailed

flowchart TB
  subgraph Instrumented[Services]
    A[Service A]
    B[Service B]
    C[Service C]
    SDK([OTel SDK])
    HOOK[Auto-instrumentation]
  end

  subgraph Context[Context propagation]
    HDR[W3C traceparent / tracestate]
    BAG[Baggage]
    QP[[Queue headers]]
  end

  subgraph Collection
    OTELC[OTel Collector]
    SAMP1([Head sampler])
    SAMP2([Tail sampler])
    BATCH[Batching exporter]
  end

  subgraph Store[Storage]
    SS[Span storage<br/>Cassandra / OpenSearch / Tempo S3]
    IDX[(Indexes:<br/>service, operation, ts)]
    BLOOM[Bloom filter for trace IDs]
  end

  subgraph Query
    UI[Jaeger / Tempo UI]
    LINK[Link: metric exemplar -> trace]
    SVCMAP[Service map auto-derived]
  end

  subgraph SLO
    LAT[p99 latency]
    ERR[Error spans]
    SAM[Adaptive sampling tuning]
  end

  Instrumented --> Context --> Collection --> Store --> Query
  SLO --- Query

    classDef client fill:#dbeafe,stroke:#1e40af,stroke-width:1px,color:#0f172a;
    classDef edge fill:#cffafe,stroke:#0e7490,stroke-width:1px,color:#0f172a;
    classDef service fill:#fef3c7,stroke:#92400e,stroke-width:1px,color:#0f172a;
    classDef datastore fill:#fee2e2,stroke:#991b1b,stroke-width:1px,color:#0f172a;
    classDef cache fill:#fed7aa,stroke:#9a3412,stroke-width:1px,color:#0f172a;
    classDef queue fill:#ede9fe,stroke:#5b21b6,stroke-width:1px,color:#0f172a;
    classDef compute fill:#d1fae5,stroke:#065f46,stroke-width:1px,color:#0f172a;
    classDef storage fill:#e5e7eb,stroke:#374151,stroke-width:1px,color:#0f172a;
    classDef external fill:#fce7f3,stroke:#9d174d,stroke-width:1px,color:#0f172a;
    classDef obs fill:#f3e8ff,stroke:#6b21a8,stroke-width:1px,color:#0f172a;
    class A,B,C,HOOK,BAG,BATCH,SVCMAP,LAT,ERR,SAM service;
    class IDX datastore;
    class QP queue;
    class SAMP1,SAMP2 compute;
    class SS storage;
    class SDK,HDR,OTELC,BLOOM,UI,LINK obs;

Glossary & fundamentals

Concepts referenced in this design. Each row links to its canonical page; the tag column shows whether it is a high-level (HLD) or low-level (LLD) concept.

Tag	Concept	What it is	Page
HLD	Probabilistic data structures	Bloom, HLL, Count-Min, MinHash, t-digest	probabilistic-data-structures
HLD	Observability	metrics, logs, traces, SLOs	observability