Assume that there is a Hadoop Cluster that has 20 machines. Out of those 20 machines 18 machines are slaves and machine 19 is for NameNode and machine 20 is for JobTracker.
Now i know that hadoop software has to be installed in all those 20 machines.
but my question is which machine is involved to load a file xyz.txt in to Hadoop Cluster. Is that client machine a separate machine . Do we need to install Hadoop software in that clinet machine as well. How does the client machine identifes Hadoop cluster?
You are correct. A client machine is needed to load the file and you will need the Hadoop libraries to be installed on the client node.
The client node will know how to identifies the Hadoop cluster using the Name Node IP and Port. These days, Task Tracker is not used, so you will need the Yarn Resource Manager IP and Port.