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 ...
Get Hadoop Beginner's Guide now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.