equests a computer system is expecting. Hadoop utilizes five such daemons and which are the following:   NameNode: It works on the Master System. The primary goal of NameNode is to manage and store all the meta-data.  Secondary NameNode: It is responsible for the backup of NameNode and stores the entire meta-data of data nodes.  DataNode: It runs on the Slave System. It serves the read/write request from the client.  JobTracker: It is used for creating and running jobs. It runs on data nodes and allocates the job to TaskTracker.  TaskTracker: It is used for creating and running jobs. It runs on data nodes and allocates the job to TaskTracker.