Hadoop Client Node Configuration

Question

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.<

Answer 1

Typically in case you have a multi tenant cluster (which most hadoop clusters are bound to be) then ideally no one other than administrators have access to the machines that are the part of the cluster.

Developers setup their own "edge-nodes". Edge Nodes basically have hadoop libraries and have the client configuration deployed to them (various xml files which tell the local installation where namenode, job tracker, zookeeper etc are core-site, mapred-site, hdfs-site.xml). But the edge node does not have any role as such in the cluster i.e. no persistent hadoop services are running on this node.

Now in case of a small development environment kind of setup you can use any one of the participating nodes of the cluster to run jobs or run shell commands.

So based on your requirement the definition and placement of client varies.