What are ZooKeeper and KRaft in the context of Kafka? What is the difference?

ZooKeeper is a distributed coordination service that Kafka uses to manage cluster metadata, select partition leaders, and store broker state information. It ensures consistency and reliability in a distributed system.

KRaft (Kafka Raft Metadata mode) is Kafka's native metadata management mechanism based on the Raft algorithm. It allows Kafka to operate without an external ZooKeeper service, simplifying architecture and reducing operational complexity.

Main differences:

• ZooKeeper — an external component requiring separate deployment and support.
• KRaft — an integrated Kafka mechanism that eliminates dependency on ZooKeeper.
• KRaft provides easier scaling and cluster management.

Thus, KRaft is an evolution of metadata management in Kafka aimed at improving ease of operation and fault tolerance.