You must enable Spark applications in cluster mode when JAR files are on the Cassandra File System (CFS) and authentication is enabled. When the application is submitted in cluster mode and the JAR files are on CFS, the Spark Worker process is responsible for obtaining the required JAR file. When authentication is required, the Spark Worker process requires the authentication credentials to CFS. The Spark Worker starts executors for unrelated Spark jobs, so giving the Spark Worker process credentials enables all future Spark jobs to pull JAR files from CFS for their dependencies. Credentials that are granted to the Spark Worker must be considered "shared" among all submitted applications, regardless of the submitting user. Shared credentials do not apply to accessing CFS from the application code.