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Kafka Is Fun

Intermediate8 min

Triage a Dead Letter Queue Flood

Practice sampling and classifying a DLQ flood instead of reacting to it message-by-message.

This lab is a paper-and-CLI exercise rather than a cluster-simulator one: a connector's DLQ topic has grown from near-zero to 25,000 messages in the last hour. The instinct is to start reading — the better move is to sample first and let the pattern tell you what actually broke.

The steps below reference the interactive simulator, which is being migrated into /simulate next — until it lands, treat this as the written runbook for the exercise.

Steps

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Verification

You can explain, in under a minute, what the single root cause was, how you found it without reading all 25,000 messages, and what you'd check before replaying.

The interview angle

This lab mirrors a real on-call scenario. The answer interviewers want to hear is 'sample, classify, diagnose, fix at source' — not 'I'd go through the messages one by one.'