Hadoop server roles

Hadoop server roles

There are mainly three machines in Hadoop deployment.

1. Master nodes. 
2. Slave nodes. 
3. Client nodes.

1. Master nodes: 

• Master nodes mainly will do two things. 
• How and where the data is storing. 
• How to process the stored data in parallel way. 

• Master node having master daemons 
• Master daemons are Name node and Job Tracker 
• Name node coordinates with HDFS to store the data 
• Job Tracker coordinates with MapReduce to process the data in parallel way. 

2. Slave nodes

• Slave nodes will store the actual data (raw data), and running the computations over the data 
• Slave nodes having slave daemons. 
• Slave daemons are Data node and Task tracker. 
• Data node is slave to the Name node
• Data node will communicate with Name node to receive the instructions. 
• Task tracker is slave to the Job tracker
• Task tracker will communicate with Job tracker to receive the instructions. 
• So, Slave Daemons work as per the Master Daemons instructions.

3. Client nodes

• The main role of client node is to load the data into the cluster. 
• Submit the MapReduce jobs. 
• MapReduce job describes how that data should be processed. 
• Client node will receives the final results from finished jobs.

Thanks for your time.

-Nireekshan