Let's address the issue of including any Docker image while building data pipelines using Spring Cloud Data Flow, which can natively interpret only Spring Boot images.
Here is a tutorial on how to use NiFi 1.0.0's zero-master clustering that uses Zookeeper so that there is never an issue of a cluster dying because of one master node going down.
Look at containerizing a Spring Data Cassandra Application. More specifically, how to put a Spring application that connects to a Cassandra database into containers.