Setup- Standalone Kafka instance
- MySQL database as event store
- Command service implemented using SpringBoot and AxonFrameowrk Kafka Extension
- Command Service is deployed on K8S cluster
Test Scenario### JMeter script with 500 concurrent test users firing command over REST- Command Service with single instance - All Successfull
Command Service scaled to 2 instances - All Successfull
Command Service scaled to 3 or 4 instances - Errros observed for certain requests with exception as below
ERROR[0;39m o.a.c.c.C.[.[.[.[dispatcherServlet].log - Servlet.service() for servlet [dispatcherServlet] in context with path  threw exception [Request processing failed; nested exception is org.axonframework.messaging.EventPublicationFailedException: Event publication failed: Exception occurred while committing kafka transaction]
Checked the kafka extenstion source and could see this exception is mapped to
Seems its generating duplicate event / transaction ids when command services are horizontally scaled.
Please suggest remidy or alternative to avoid these exceptions.