What is the role of a Kafka broker?

A Kafka broker is a server in the Kafka cluster that stores partition data and handles producer and consumer requests. Each broker can host multiple partition replicas. One broker per partition is the leader (handles all reads and writes for that partition); others are followers (replicate the leader). A cluster has multiple brokers for fault tolerance and scalability. The controller broker manages cluster metadata including leader elections and partition assignments.

Expected key concepts: server, partition data, producer, consumer, leader, follower, replicate, controller, metadata, leader elections