Explanation: A developer will configure their machine to run in Pseudo-Distributed mode
This effectively creates a single machine cluster All five Hadoop daemons are running on the same machine Very useful for testing code before it is deployed to the real cluster
Refer HadoopExam.com Recorded Training Module : 14 and 16
Explanation: Hadoop is comprised of five separate daemons
NameNode : Holds the metadata for HDFS
Secondary NameNode : Performs housekeeping functions for the NameNode - Is not a backup or hot standby for the NameNode DataNode : Stores actual HDFS data blocks