This document provides an overview of the Hadoop framework and its key components. It describes the roles of the Master node, NameNode, DataNodes, JobTracker, SecondaryNameNode, and TaskTracker. The NameNode manages the file system namespace and regulates access to files. DataNodes store data blocks and serve read/write requests. The JobTracker coordinates jobs on Hadoop and assigns tasks to TaskTrackers on slave nodes. The SecondaryNameNode aids the NameNode in the event of failure.