To launch a Kafka consumer I have to run it with the following params.
kafka-console-consumer.bat --zookeeper localhost:2181 --topic MyTopic
Was wondering why it needs to have a zookeeper as a param, if I use the broker param will it not work similar to how the producer is launched. Consumer needs to be aware of the broker/cluster and not the zookeeper location.
.\kafka-console-producer.bat --broker --list localhost:9092 --topic MyTopic
This is on windows, am not sure how its in Unix flavors.
-Chandra
You're invoking the old Kafka Consumer. Old consumer requires zookeeper to co-ordinate from which broker to fetch data.
The new consumer don't requires the zookeeper parameter.
.\kafka-console-consumer.bat --bootstrap-server localhost:9092 --topic MyTopic --new-consumer
Optionally, you can add --from-beginning argument to read the old records in the topic.
Related
I only changed the paths to logs and zookeeper-data in configs.
Running zookeeper:
zookeeper-server-start.bat D:\__programs\kafka_2.12-2.1.0\config\zookeeper.properties
Running kafka:
kafka-server-start.bat D:\__programs\kafka_2.12-2.1.0\config\server.properties
Running consumer:
kafka-console-consumer.bat -bootstrap-server localhost:2181 -topic mytopic
Running producer:
kafka-console-producer.bat -broker-list localhost:9092 -topic mytopic
So, consumer can only get messages when it's on the same port(9092) with a producer.
What's the problem here?
Consumers and producers are clients of Kafka server so they both can use same port as we configured as a client port within server.properties file.
Port is configured within config/server.properties file with either one of these parameters
advertised.listeners
listeners
Depends on configuration and protocol consumers and producers can use multiple ports.
You can find details of broker parameters here
Bootstrap server and Broker list, both should point to the same
Since you are producing events on localhost:9092, you should use the same in consumer as below:
kafka-console-producer.bat --broker-list localhost:9092 --topic mytopic
kafka-console-consumer.bat --bootstrap-server localhost:9092 --topic mytopic
P.S. Usually 2181 port is assigned to zookeeper process. And here localhost:2181 will refer to Zookeeper.
I used kafka version 2.10-0.9.0.1, all information goes to zookeeper so i used the following command to checke kafka Lag:
./kafka-run-class.sh kafka.tools.ConsumerOffsetChecker --group
group-name --topic topicName --zookeeper zooIp:2181
Now we used latest kafka version 2.11-0.11.0.0, here this command not works.
How we see the kafka lag of topics.
The offsets are not stored anymore in Zookeeper but directly in Kafka now.
You can use the kafka-consumer-groups tool (kafka.admin.ConsumerGroupCommand) to retrieve the position/lag of a group.
bin/kafka-consumer-groups.sh --bootstrap-server KAFKA_HOST:KAFKA_PORT --describe --group GROUP_NAME
./bin/kafka-console-consumer.sh --zookeeper 127.0.0.1:2181 --topic test
./bin/kafka-console-producer.sh --broker-list 127.0.0.1:9092 --topic test
Why to consume kakfa needed zookeeper?
could I consume kafka from brokers ?
--zookeeper is an outdated option (for the old Consumer).
Use the newer --bootstrap-server option with kafka-console-consumer.
More info: http://kafka.apache.org/documentation/#newconsumerconfigs
I am playing aroung Kafka, when I use
bin/kafka-console-consumer.sh --zookeeper localhost:2181 --from-beginning --topic test
Kafka will automatically create a consumer group. I am wondering how to get the consumer group name?
You should use kafka-consumer-groups.sh. The following command will list you all consumer groups.
bin/kafka-consumer-groups.sh --list --bootstrap-server localhost:9092
Note: This will only show information about consumers that use the Java Consumer API (non-Zookeeper-based consumers).
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?
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.
Hi The actual problem lies in the syntax, from version to verison it keeps on changing.
./kafka-console-consumer.sh --bootstrap-server localhost:9092 --from-beginning --topic muleesb
would work for you
Reason
For kafka versions above kafka_2.11-2.1.0: ./kafka-console-consumer.sh --bootstrap-server IP:PORT --from-beginning --topic TOPIC
For Kafka versions kafka_2.11_0.9.0.0 and below: /kafka-console-consumer.sh --zookeeper IP:PORT —-topic TOPIC --from-beginning --whitelist TOPIC
Exactly one of whitelist/blacklist/topic is required
As mentioned by Harald, use whitelist / blacklist option to include / exclude a set of topics for consumption.
sh kafka-console-consumer.sh --zookeeper localhost:2181 --from-beginning --whitelist Hello,World