Apache Spark, is an open source cluster computing framework originally developed at University of California, Berkeley but was later donated to the Apache Software Foundation where it remains today. In contrast to Hadoop’s two-stage disk-based MapReduce paradigm, Spark’s multi-stage in-memory primitives provides performance up to 100 faster for certain applications.

RDD’s:

Spark has a driver program where the application logic execution is started, with multiple workers which processing data in parallel.
The data is typically collocated with the worker and partitioned across the same set of machines within the cluster.  During the execution, the driver program will pass the code/closure into the worker machine where processing of corresponding partition of data will be conducted.
The data will undergoing different steps of transformation while staying in the same partition as much as possible (to avoid data shuffling across machines).  At the end of the execution, actions will be executed at…