Kafka consumer console subscribing to multiple topics

Question

I use Ubuntu server 16.04 to try using Kafka. For the command to start a producer and a consumer console I use the following.

producer console :

bin/kafka-console-producer.sh --broker-list localhost:9092 --topic hello-topic

consumer console :

bin/kafka-console-consumer.sh --zookeeper localhost:2181 --from-beginning --topic hello-topic

but the command above only subscribes to one topic. How can I subscribe to multiple topics?

Answer 1

First you should connect with the option bootstrap-server to the Kafka server itself not the zookeeper server.

For multiple topics you use the whitelist option. This will get interpreted as a regular expression and has to get quoted, see Kafka documentation. So a correct command would be:

kafka-console-consumer.sh --bootstrap-server localhost:9092 --whitelist 'hello-topic|world-topic|another-topic'

Other expressions are also possible, like

kafka-console-consumer.sh --bootstrap-server localhost:9092 --whitelist '.*'

---

BE AWARE

For convenience we allow the use of ',' instead of '|' to specify a list of topics.

Does not work with Kafka 2.0, perhaps only when mirroring, which I did not try yet.