This is the kind of question where you can talk for 45 minutes and still feel like you barely scratched the surface.
Start by clarifying requirements and scale, then design a high-level architecture with core components like producers, brokers, topics, partitions, and consumers. Dive into critical details such as replication, durability, ordering, and delivery semantics, and discuss trade-offs for each design decision.
Pro tip: Emphasize how your design handles failures and scales horizontally, and proactively compare your choices to Kafka's approach to show deep understanding.
Ask about expected throughput, latency, durability, ordering guarantees, and consumer models to scope the design appropriately.
Outline the main components: producers, brokers, topics, partitions, consumers, and a coordination service (e.g., ZooKeeper/KRaft). Explain how they interact.
Describe how messages are stored (e.g., append-only log, segments), partitioned for parallelism, and indexed for efficient consumption.
Discuss replication for fault tolerance, leader election, handling broker failures, and scaling partitions and consumers.
Explain at-least-once, at-most-once, and exactly-once semantics, and trade-offs between consistency, availability, and latency.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.