What problems with Kafka have you encountered? How did you solve them?

One common issue when working with Kafka is message processing delays due to consumer overload or incorrect partition configuration. To address this, I optimized the number of partitions and consumers to ensure load balancing and increase parallelism.

Another frequent case is message loss during failures. To prevent this, I used acks=all settings on the producer and enabled automatic message acknowledgment on the consumer side with offset control.

I also encountered the problem of consumer 'sticking' due to improper offset management. I resolved this by explicitly committing offsets after successful message processing to avoid reprocessing or data skipping.

An example of a producer configuration with acknowledgment of all replicas:

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("acks", "all");
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
KafkaProducer<String, String> producer = new KafkaProducer<>(props);

Overall, the key to solving Kafka issues is proper parameter configuration, cluster health monitoring, and effective offset management.