Apache Kafka

Consumer Commands

Kafka consumers read messages from topics. Master the console consumer for debugging and understand consumer group behavior.

7 commands

Pro Tips

Use --from-beginning to see all messages, not just new ones.

Add --property print.key=true to see message keys alongside values.

Common Mistakes

Console consumers without --group don't commit offsets.

Commands

Console consumer

$ kafka-console-consumer.sh --topic my-topic --bootstrap-server localhost:9092

Consume new messages.

From beginning

$ kafka-console-consumer.sh --topic my-topic --bootstrap-server localhost:9092 --from-beginning

Consume all messages from start.

With keys

$ kafka-console-consumer.sh --topic my-topic --bootstrap-server localhost:9092 --property print.key=true --property key.separator=:

Show message keys.

With timestamps

$ kafka-console-consumer.sh --topic my-topic --bootstrap-server localhost:9092 --property print.timestamp=true

Show message timestamps.

Specific partition

$ kafka-console-consumer.sh --topic my-topic --bootstrap-server localhost:9092 --partition 0 --offset earliest

Consume from specific partition.

Max messages

$ kafka-console-consumer.sh --topic my-topic --bootstrap-server localhost:9092 --max-messages 10

Consume limited number of messages.

Consumer group

$ kafka-console-consumer.sh --topic my-topic --bootstrap-server localhost:9092 --group my-group

Consume as part of consumer group.