Apache Kafka Guide #27 Consumer Groups CLI & Resetting Offset

Apache Kafka Guide Consumer Groups CLI Resetting Offset

Hi, this is Paul, and welcome to the #27 part of my Apache Kafka guide. Today we will discuss how to use Apache Kafka Consumer Groups CLI.

Apache Kafka At the Gates of Mastery: Kafka Core

List all Consumer Groups

kafka-consumer-groups.sh --bootstrap-server localhost:9092 --list

And we have all consumer groups including temporary ones. Temporary it’s the groups created automatically when you run consumer without specifying the group will be named like console-consumer-48392 and it will be deleted automatically in some amount of time, you do need to carry about it.

Describe Consumer Group

kafka-consumer-groups.sh --bootstrap-server localhost:9092 --describe --group group-name

Delete Consumer Group and Resetting Offsets

kafka-consumer-groups.sh --bootstrap-server localhost:9092 --delete --group group-name

It’s possible for groups without active Consumers this delete all information about Consumer Group inclusive offsets.

Resetting Offsets

It is possible to reset the application’s offsets to the very start to reprocess all messages. This capability is provided by Kafka consumer groups through a feature known as “reset offsets”. By using the command --reset-offsets, we can adjust the offsets to-earliest, targeting the initial data available within the topic. To preview the outcome of this adjustment without making actual changes, we employ the --dry-run option, which reveals the intended assignment.

kafka-consumer-groups.sh --bootstrap-server localhost:9092 --group group-name --reset-offsets --to-earliest --topic topic-name --dry-run

--dry-run — used for testing purposes just watch what happen

Instead of using the --dry-run option, for real execution we use -- execute. This action effectively resets the offsets. Currently, if we apply the --execute command, the new offsets will be set to 0.

kafka-consumer-groups.sh --bootstrap-server localhost:9092 --group group-name --reset-offsets --to-earliest --topic topic-name --execute

Reminder you always can see all the features in the documentation, just:

$ kafka-consumer-groups to the console.

Thank you for reading until the end. Before you go:

Apache Kafka At the Gates of Mastery: Kafka Core

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