This document summarizes Spark and Spark Streaming internals. It discusses the Resilient Distributed Dataset (RDD) model in Spark, which allows for fault tolerance through lineage-based recomputation. It provides an example of log mining using RDD transformations and actions. It then discusses Spark Streaming, which provides a simple API for stream processing by treating streams as series of small batch jobs on RDDs. Key concepts discussed include Discretized Stream (DStream), transformations, and output operations. An example Twitter hashtag extraction job is outlined.