intermediate
Producer
Make producers explicit about message schema, keys, durability expectations, retry policy, observability, and publish failure handling.
Producers define message payload schema, keys for partitioning, durability expectations (acks), compression, and failure handling when publish fails. Observability includes publish latency, error rate, and serialization failures.
Trade-off: stronger durability (wait for all replicas) versus lower latency and higher throughput.
On interviews: configure Kafka producer acks for payment events versus metrics; idempotent producer settings.
Common pitfalls: publishing huge payloads; no schema version; fire-and-forget without monitoring; wrong partition key breaking ordering.
Checklist:
- Version schemas and document compatibility.
- Choose keys for ordering and load balance.
- Set acks and retries with idempotency.
- Metric failed publishes and buffer saturation.