September 21, 2021

Apache Kafka 3.0 - Improving KRaft and an Overview of New Features

15 minutes

Apache Kafka® 3.0 is out! To spotlight major enhancements in this release, Tim Berglund (Apache Kafka Developer Advocate) provides a summary of what’s new in the Kafka 3.0 release from Krakow, Poland, including API changes and improvements to the early-access Kafka Raft (KRaft).

KRaft is a built-in Kafka consensus mechanism that’s replacing Apache ZooKeeper going forward. It is recommended to try out new KRaft features in a development environment, as KRaft is not advised for production yet. One of the major features in Kafka 3.0 is the efficiency for KRaft controllers and brokers to store, load, and replicate snapshots into a Kafka cluster for metadata topic partitioning. The Kafka controller is now responsible for generating a Kafka producer ID in both ZooKeeper and KRaft, easing the transition from ZooKeeper to KRaft on the Kafka 3.X version line. This update also moves us closer to the ZooKeeper-to-KRaft bridge release. Additionally, this release includes metadata improvements, exactly-once semantics, and KRaft reassignments.

To enable a stronger record delivery guarantee, Kafka producers turn on by default idempotency, together with acknowledgment delivery by all the replicas. This release also comprises enhancements to Kafka Connect task restarts, Kafka Streams timestamp based synchronization and more flexible configuration options for MirrorMaker2 (MM2). The first version of MirrorMaker has been deprecated, and MirrorMaker2 will be the focus for future developments. Besides that, this release drops support for older message formats, V0 and V1, as well as initiates the removal of Java 8 and Scala 2.12 across all components in Apache Kafka. The universal Java 8 and Scala 2.12 deprecation is anticipated to complete in the future Apache Kafka 4.0 release.

Apache Kafka 3.0 is a major release and step forward for the Apache Kafka project!

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