In this article, I am going to explain how to use Hadoop streaming with Perl scripts. First, let’s understand some theory behind Hadoop streaming. Hadoop has been written in Java. Therefore, the native language to write MapReduce program is Java. But, Hadoop also provide an API to MapReduce that allows …
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Implementing Security in Hadoop Cluster
When we talk about security in Hadoop, we need to explore all the aspect of cluster networking and understand how the Nodes and Client communicate to each other. Let’s list down possible communication in a simple cluster. Master – Slave communication => Namenode – Datanode / Jobtracker – Tasktracker communication …
Tool & ToolRunner – Simplifying the concept
Writing a mapper & reducer Program definition is easy. Just extend your class by org.apache.hadoop.mapreduce.Mapper and org.apache.hadoop.mapreduce.Reducer respectively and override the map and reduce methods to implement your logics. But, when it comes to write driver program (contain main method of program) for the MapReduce Job, it’s always preferable to …