Hadoop modes of operation

·       

            STAND ALONE

·         PSEUDO DISTRIBUTED

·         FULLY DISTRIBUTED (Cluster)

The STAND ALONE and PSEUDO DISTRIBUTED modes of operations are development modes of operations used by development teams to carry out development of Map Reduce jobs.

The stand-alone mode of development does not use HDFS but uses local operating system files system. Hadoop and all application code runs inside a single Java process. This is on a Single machine.

The pseudo – distributed mode of Hadoop runs all the processes like Name node, Data node, Job Tracker and Task Tracker as separate processes. HDFS file system is used in this mode of operation. This is again on a single machine.

Both the above approaches are used by developers to carry out development activities.

The third mode of Hadoop operation is FULLY DISTRIBUTED Cluster. HDFS file system is used. This is over a cluster of machines. Read / write processes are balanced over a cluster of nodes.  There are several daemon threads of Name node, Data node, Task Tracker and Job Tracker.