Time for action – using Hadoop to calculate Pi
We will now use a sample Hadoop program to calculate the value of Pi. Right now, this is primarily to validate the installation and to show how quickly you can get a MapReduce job to execute. Assuming the HADOOP_HOME/bin directory is in your path, type the following commands:
$ Hadoop jar hadoop/hadoop-examples-1.0.4.jar pi 4 1000 Number of Maps = 4 Samples per Map = 1000 Wrote input for Map #0 Wrote input for Map #1 Wrote input for Map #2 Wrote input for Map #3 Starting Job 12/10/26 22:56:11 INFO jvm.JvmMetrics: Initializing JVM Metrics with processName=JobTracker, sessionId= 12/10/26 22:56:11 INFO mapred.FileInputFormat: Total input paths to process : 4 12/10/26 22:56:12 INFO mapred.JobClient: Running ...
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