Kafka Essentials cheat sheet with Shrividya Hegde

Kafka's mental model is small but easy to get wrong, and getting it wrong shows up as data loss or a stalled consumer group at 3am. This sheet covers the model and the configs together.

Two pages:

• The core model, with a diagram mapping partitions to consumers in a group
• Producer configs, and why the safe settings are already your defaults since 3.0
• Replication, ISR, and why min.insync.replicas and acks=all only work as a pair
• Consumer groups, offset commits, and max.poll.interval.ms
• Delivery semantics, with a straight answer on when exactly-once is worth the complexity
• Retention vs compaction, partitioning strategy, schema management
• CLI commands, including the consumer lag check you'll run most

Current through Kafka 4.0: ZooKeeper is removed, clusters are KRaft only, and the new KIP-848 rebalance protocol needs consumers to opt in. All flagged on the sheet.