Note: this is not about replacing ZooKeeper in general with Kafka as the title might suggest, it's about Kafka considering an alternative to its internal use of ZooKeeper:
"Currently, Kafka uses ZooKeeper to store its metadata about partitions and brokers, and to elect a broker to be the Kafka Controller. We would like to remove this dependency on ZooKeeper. This will enable us to manage metadata in a more scalable and robust way, enabling support for more partitions. It will also simplify the deployment and configuration of Kafka"
"Currently, Kafka uses ZooKeeper to store its metadata about partitions and brokers, and to elect a broker to be the Kafka Controller. We would like to remove this dependency on ZooKeeper. This will enable us to manage metadata in a more scalable and robust way, enabling support for more partitions. It will also simplify the deployment and configuration of Kafka"