Hi folks, In my project, we want to perform to update our active Kafka 0.8 cluster to Kafka 0.8.1.1 without downtime and losing any data. The process (after reading http://kafka.apache.org/documentation.html#upgrade) looks to me like this. For each broker in turn:
1. Bring the broker down. 2. Update Kafka to 0.8.1.1 on the broker node. 3. Start the broker. 4. Run preferred-replica-election script to restore broker's leadership for respective partitions. 5. Wait for the the preferred replica election to complete. I deem step#5 necessary since preferred replica election is an asynchronous process. There is a slim chance that bringing other brokers down before the election is complete would result in all replicas down for some partitions, so a portion of the incoming data stream would be lost. Is my understanding of the process correct?
