Useful if you need to change the replication factor of an already created Kafka topic. It creates the JSON necessary for the kafka command kafka-reassign-partitions.

In the generate-kafka-replication-factor-json.sh file, you just have to change the values of the following variables to match your needs:

• BROKER_IDS
• NUMBER_OF_PARTITIONS
• NUMBER_OF_REPLICAS
• TOPIC_NAME

It will generate the result in a increase-replication-factor.json file.

Now you just have to use this JSON with the kafka-reassign-partitions Kafka command:

$ ./kafka-reassign-partitions.sh --zookeeper localhost:2181 --reassignment-json-file increase-replication-factor.json --execute

You can check your new replication policy worked with:

$ ./kafka-topics.sh --zookeeper localhost:2181 --topic topic --describe