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).
Related
When I run two instances of Kafka-console-consumers with the exact same properties (using the default one config/consumer.properties), I get same messages on both the instances.
./bin/kafka-console-consumer.sh --bootstrap-server :9092 --topic test1
If both the instances have the same consumer group id, shouldn't Kafka send a given message to only one of the consumers? How to run them as one consumer group?
From kafka docs i found this
The default for console consumer's enable.auto.commit property when no group.id is provided is now set to false. This is to avoid polluting the consumer coordinator cache as the auto-generated group is not likely to be used by other consumers.
But here is the trick, use this command to list all consumer groups across all topics, as you said i have opened four console consumers and i want to check list of consumer groups consuming from that topic
bin/kafka-consumer-groups.sh --bootstrap-server localhost:9092 --list
Every console consumer start with different group id, this is the reason always consuming from beginning addition of this property (--from-beginning)
ups.sh --bootstrap-server localhost:9092 --list
Note: This will not show information about old Zookeeper-based consumers.
console-consumer-66835
console-consumer-38647
console-consumer-18983
console-consumer-18365
console-consumer-96734
Okay easiest way to set group.id for console consumer
bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test --from-beginning --consumer-property group.id=test1
Read up Managing Consumer Groups.
The trick is to use --consumer.config config/consumer.properties or --consumer-property group.id=test1 that would specify the group.id explicitly.
./bin/kafka-console-consumer.sh \
--bootstrap-server localhost:9092 \
--topic test1 \
--consumer.config config/consumer.properties
kafka-consumer-groups.sh --bootstrap-server hostname:port --describe --group sub1
Consumer group 'sub1' has no active members.
kafka-consumer-groups.sh --bootstrap-server hostname:port --delete --group sub1
Option '[delete]' is only valid with '[zookeeper]'.
Note that there's no need to delete group metadata for the new consumer as the group is deleted when the last committed offset for that group expires.
Also when i try to display my consumer details using zookeeper , It tells consumer "sub1" not available.
kafka-consumer-groups.sh --zookeeper hostname:port --describe --group sub1
Note: This will only show information about consumers that use ZooKeeper (not those using the Java consumer API).
Error: The consumer group 'sub1' does not exist.
Group information for consumers that use Kafka to manage offsets instead of Zookeeper cannot be deleted with built-in tools. If you read the whole warning when trying to execute
kafka-consumer-groups.sh --bootstrap-server hostname:port --delete --group sub1
it clearly mentions why group metadata info cannot be deleted:
Option '[delete]' is only valid with '[zookeeper]'.
Note that there's no need to delete group metadata for the new consumer as the group is deleted when the last committed offset for that group expires.
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
I want to delete a Kakfa consumer group so that when the application creates a consumer and subscribes to a topic it can start at the beginning of the topic data.
This is with a single node development vm using the current latest Confluent Platform 3.1.2 which uses Kafka 0.10.1.1.
I try the normal syntax:
sudo /usr/bin/kafka-consumer-groups --new-consumer --bootstrap-server localhost:9092 --delete --group my_consumer_group
I get the error:
Option [delete] is only valid with [zookeeper]. Note that there's no need to delete group metadata for the new consumer as the group is deleted when the last committed offset for that group expires.
If I try the zookeeper variant:
sudo /usr/bin/kafka-consumer-groups --zookeeper localhost:2181 --delete --group my_consumer_group
I get:
Delete for group my_consumer_group failed because group does not exist.
If I list using the "old" consumer, I do not see my consumer group (or any other consumer groups)
sudo /usr/bin/kafka-consumer-groups --zookeeper localhost:2181 --list
If I list using the "new" consumer, I can see my consumer group but apparently I can't delete it:
sudo /usr/bin/kafka-consumer-groups --new-consumer --bootstrap-server localhost:9092 --list
This can be done with Kafka 1.1.x. From the documentation:
bin/kafka-consumer-groups.sh --bootstrap-server localhost:9092 --delete --group my-group --group my-other-group
In Kafka 0.11 (or Confluent 3.3) you can reset the offsets of any existing consumer group without having to delete the topic. In fact you can change the offsets to any absolute offset value or timestamp or any relative position as well.
These new functions are all added with the new --reset-offsets flag on the kafka-consumer-groups command line tool.
See KIP-122 details here https://cwiki.apache.org/confluence/display/KAFKA/KIP-122%3A+Add+Reset+Consumer+Group+Offsets+tooling
Upgrading to the just released Confluent Platform 3.2 with Kafka 0.10.2 solved my underlying issue. When I delete a topic, offset information is now correctly reset. So when I create a topic with the same name, consumers start from the beginning of the new data.
I still can't delete new style consumer groups with the kafka-consumer-groups tool, but my underlying issue is solved.
Before Kafka 0.10.2, there were hacks, but no clean solution to this issue.
If you use Java client, you can first get the beginning offset.
TopicPartition partition = new TopicPartition("YOUR_TOPIC", YOUR_PARTITION);
Map<TopicPartition, Long> map = consumer.beginningOffsets(Collections.singleton(partition));
And the offset that consumer using to start processing, (if not delete the consumer group).
Long committedOffset = consumer.committed(partition).offset();
Now, if you think start from committedOffset is ok, just poll records.
if you want the beginning offset,
consumer.seek(partition, map.get(partition));
you can also reset the offset of single topic without deleting the entire consumer group :
bin/kafka-consumer-groups.sh --bootstrap-server localhost:9092 --group my-group --topic my-topic --reset-offsets --to-earliest --execute
If you're using Windows and you need a JAAS config with password & username to access your kafka cluster, you can use the following commands
#consumer.properties
sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required username="XXXXXXXXXXXXXXX" password="XXXXXXXXXXXXXXXXXXX";
security.protocol=SASL_SSL
sasl.mechanism=PLAIN
.\kafka\bin\windows\kafka-consumer-groups.bat --bootstrap-server xxxxxxxxxx.confluent.cloud:9092 --group cop-group --topic topic_name_ini --reset-offsets --to-earliest --execute --command-config .\kafka\config\consumer.properties
In the command above we used --command-config to pass a properties file for the JAAS config
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.