Every partition in the Kafka server has one server that plays the role of a leader.

 The leader performs all the read and write data tasks for a partition.

 A partition can have no followers, one follower, or more than one follower. 

The job of the follower is to replicate the leader. 

In such a case, if there is a failure in the leader, then one of the followers can take on the leader's load.

https://kafka.apache.org/20/documentation.html#:~:text=Each%20partition%20has%20one%20server,followers%20passively%20replicate%20the%20leader.