If you upgrade ApsaraMQ for Kafka brokers, note the following possible impacts:
During the upgrade, all brokers in the ApsaraMQ for Kafka cluster are restarted one by one. Services are not interrupted, but messages consumed within 5 minutes after each broker is restarted may be out of order in specific partitions. Serverless ApsaraMQ for Kafka and ApsaraMQ for Confluent instances fully comply with Apache Kafka semantics during version upgrades.
During broker restarts, clients that are connected to the brokers may be disconnected. If the clients support automatic reconnection, other brokers automatically take over the services.
During the upgrade and restart of brokers, message traffic may be unevenly distributed across partitions. You must evaluate the impact on your business.
Broker IP addresses may change in some scenarios. Make sure that clients connect to Kafka by using domain names instead of fixed IP addresses.
It takes about 5 to 15 minutes to upgrade all brokers. If you have multiple instances, we recommend that you first upgrade a test cluster and verify the upgrade results before upgrading your production cluster.
If you use a Go client developed with the Sarama library, messages may be repeatedly consumed when you upgrade brokers. For more information, see Why is the Sarama Go client not recommended?