In cases where more machines are added to the Kafka cluster, increasing the replication factor means moving replicas for a topic to these new machines.
For this recipe, Kafka must be installed, ZooKeeper running, and the broker running with some topics created on it with some replicas. Start new nodes and add them to this cluster.
This example increases the replication factor of partition 0 of the topic topic_1 from 2 to 4. Before the increment, the partition's only replica existed on brokers 3 and 4. This example adds more replicas on brokers 5 and 6.
Create a JSON file named
increase-replication.jsonwith this code:
$cat increase-replication.json{"version":1,"partitions":[{"topic":"topic_1","partition":0,"replicas":[3,4,5,6]}]}
- Then, run the following command:
$ bin/kafka-reassign-partitions.sh --zookeeper localhost:2181 --reassignment-json-file increase-replication-factor.json --execute