Currently, these add-ons must be added to the SonataFlow builder image in order to support an external Data Index:

• kogito-addons-quarkus-events-process
• kogito-addons-quarkus-process-management
• kogito-addons-quarkus-source-files

See this example: https://github.com/kiegroup/kogito-examples/blob/1.43.x/serverless-workflow-examples/serverless-workflow-data-index-quarkus/pom.xml#L193-L204