When debugging Spark Streaming applications it is necessary to monitor certain metrics that are not shown in the Spark application UI. For example, what is average processing time of batches? What is the scheduling delay? Is the system able to process as fast as it is receiving data? How many records I am receiving through my receivers?
While the StreamingListener interface introduced in the 0.9 provided some of this information, it could only be accessed programmatically. A UI that shows information specific to the streaming applications is necessary for easier debugging.