Kafka does not replicate a topic to thoes brokers which were not assigned to the topic when it was created?

Question

I have a topic "reptop" with replication factor 3. My cluster consist of 4 brokers [IDs: 0,1,2,3]. When the topic was created brokers 0,2 and 3 were assigned to the topic, with leader as '2', now when one of my brokers, leader or follower goes down Kafka does not replicate the topic to broker:1 even though it is healthy and the ISR is less than replication-factor, but when the broker which had gone down and was initially assigned to the topic, comes back up kafka replicates the topic to this node. So the question is why does the kafka not replicate the topic to the brokers that were not assigned the topic when the topic was created even though there are healthy brokers on the cluster and "ISR

Answer 1

This is by design. If you want to reassign the partitions, you must do so with the reassignment tool. Another option is to bring up a new broker instance with the missing ID. Kafka does not "self heal" like say hdfs and there are many cases where you wouldn't want it to. If you want it to, there are told out there like confluent rebalancer that can be used.