Rolling Upgrade from Kafka 2 to Kafka 3

To perform a rolling upgrade from Kafka 2.8.2.3.3.6.x-x to Kafka 3.7.2.3.3.6.x-x, follow these steps:

1. Update server.properties on All Brokers. Edit server.properties and add the following property:

inter.broker.protocol.version=2.8.2.3.3.6.2-1

2. Upgrade Brokers One at a Time. On each broker, perform the following steps:

   1. Shut down the broker.
   2. Update the code by replacing the bin and libs directories with kafka_2.12-3.7.1.3.3.6.x-x.
   3. Restart the broker.

3. Verify Cluster Behavior. Once all brokers are upgraded, ensure that the cluster is functioning correctly by monitoring logs and metrics. Also try to read events from the topic which are written in the above steps:

bin/kafka-console-producer.sh --topic Test1 --bootstrap-server localhost:9092

Example output:

This is my first event

This is my second event

4. Update Protocol Version. Once satisfied with the stability, update server.properties:

inter.broker.protocol.version=3.7.2.3.3.6.2-1

5. Restart Brokers One After the Other: Restart each broker sequentially for the new protocol version to take effect.

For more details, see Upgrading Apache Kafka.