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MapReduce Tutorial : Dynamic Hadoop cluster for several computations

When multiple MR jobs should be executed, it would be better to reuse the cluster instead of allocating a new one for every computation.

A cluster can be created using

/home/straka/hadoop/bin/hadoop-cluster -c number_of_machines -w sec_to_run_the_cluster_for

The syntax is the same as in perl script.pl run.

The associated SGE job name is HadoopCluster. The running job can be stopped by either removing HadoopCluster.c$SGE_JOBID file or deleting the SGE job using qdel.

Using a running cluster

Running cluster is identified by its master. When running a Perl MR job, existing cluster can be used by

perl script.pl run -jt hostname_of_cluster_master:9001 ...


Try running the same script wordcount.pl as in the last step, by creating the cluster and submitting the job to it:

/home/straka/hadoop/bin/hadoop-cluster -c 1 -w 7200
perl wordcount.pl -jt hostname_of_cluster_master:9001 -Dmapred.max.split.size=1000000 /home/straka/wiki/cs-text-medium some_output_directory

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