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Design a distributed tracing system like jaeger

PremiumCloud infrastructureMedium

  • Distributed tracing
  • OpenTelemetry
  • Tail based sampling

Quick answer

This cloud infrastructure interview question asks you to design a distributed tracing system like jaeger. Aim for a design that runs reliably and securely in the cloud at a sensible cost, then explain the services, regions, deployment and trade-offs. Interviewers want to see how you balance reliability, security and cost.

The problem

Design a distributed tracing system like Jaeger: each request carries a trace ID across services, every service reports timed spans, and engineers open a full trace to see where time went. The hard parts are the huge span volume, sampling that still keeps slow and failed traces, and storing spans cheaply but searchably.

A span has a trace ID, a span ID, a parent span ID, a service, an operation name, a start time, a duration, a status and tags. All spans with the same trace ID form one request tree.

What must a distributed tracing system like jaeger do?

  • Context propagation: Pass trace context across HTTP, gRPC and message queues using the W3C traceparent header or the equivalent message attribute.
  • Span reporting: SDKs in each service export spans in batches to a local agent, which forwards them to collectors.
5 more requirementsUnlock to see all

How well must it do it?

  • Low overhead: Tracing adds under 1% CPU to services and never blocks a request; when buffers are full, spans are dropped.
  • Freshness: A kept trace is searchable within 1 minute of the request ending.
3 more requirementsUnlock to see all

What scale should you design for?

Use these numbers in your estimates.

The scale numbers unlock with this questionUnlock

Key concepts

  • Distributed tracing
  • OpenTelemetry
  • Tail based sampling
  • Context propagation
  • W3C traceparent
  • Span storage

How you’ll practise

6 short steps · save and come back any time
  1. Requirements
  2. Environments and topology
  3. Deployment pipeline
  4. Reliability and disaster recovery
  5. Observability and cost
  6. Wrap-up

Lala, personalized to you, gives a hint when you ask and reviews your design when you are ready.

What do interviewers look for?

In any cloud infrastructure design round.

  • Clarifies availability, security and cost targets
  • Chooses managed services with reasons
  • Plans regions, zones and failover
  • Covers identity, secrets and network boundaries
  • Explains deployment, rollback and observability
  • Keeps an eye on cost as usage grows

Questions people ask about this interview question

Which design type is this question?
It is a cloud infrastructure question. You design a distributed tracing system like jaeger and explain your choices the way you would in an interview.
Is this question asked at entry level?
It is marked Medium. Entry-level engineers can practise it, but it expects you to reason about requirements and trade-offs, not only list components.
What should I cover first?
Start with the workloads, the availability target and the security and cost limits. Agree on scope with the interviewer before you design anything.
Can I practise it for free?
It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.

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Updated · Written by the SevyDevy team

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