It maintains and manages the slave nodes and assign the task to them.
It only stores the metadata of HDFS. Namenode executes file system namespace operations like opening, closing and renaming files and directions.
All replication factor details should maintain in Name node.This metadata is available in memory in the master for faster retrieval data.
This is the daemon that runs on the slave, these are actual workers nodes that store the data. Data nodes are the slaves which are deployed on each machine and provide actual storage. Data nodes are responsible for serving read and write requests from the file system clients, also perform block creation, deletion, and replication upon instruction from the name node.
It is a daemon that runs on Master, it is responsible for dividing the tasks amongst the slaves, Name Node should be deployed on reliable Hardware, It stores Meta data about the data stored on Slaves. Whenever a data node goes down then Name Node has to send the Balancer command to store the Blocks into some other data node.
It is a Daemon that runs on Slave, It responsible for storing actual data. Data nodes can be deployed on Commodity Hardware. Data Nodes need to continuously send Heartbeats to the Name Node.