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Questions about usage of Hadoop built-in examples

+1 vote
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I am used to old version where I could use the typical hadoop-examples-*.jar with wordcount, sort or any other.

Recently I am using the latest version (2.7.1) but as can I see, there is no this dot jar file with examples. After a search over the Internet, I saw that there is a hadoop-mapreduce-examples jar file. Where I can find usage help for this examples? Available examples, etc.

I am focused on the HiBench tool (which use those examples) that Im using to test some modifications on the source code of Hadoop.

posted Sep 14, 2015 by anonymous

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1 Answer

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In 2.7.1 I am able to see /share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar which can help you run some sample MapRed Examples like wordcount/ PI

/opt/install/hadoop-2.7.1/bin$ ./yarn jar ../share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar
Listening for transport dt_socket at address: 7003 An example program must be given as the first argument.Valid program names are:
aggregatewordcount: An Aggregate based map/reduce program that counts the words in the input files.
aggregatewordhist: An Aggregate based map/reduce program that computes the histogram of the words in the input files.
bbp: A map/reduce program that uses Bailey-Borwein-Plouffe to compute exact digits of Pi.
dbcount: An example job that count the pageview counts from a database.
distbbp: A map/reduce program that uses a BBP-type formula to compute exact bits of Pi....

answer Sep 14, 2015 by Sonu Jindal
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We've tried to specify JVM flags during hadoop daemon's starts,

e.g. export HADOOP_NAMENODE_OPTS="-XX:UseNUMA -Dcom.sun.management.jmxremote $HADOOP_NAMENODE_OPTS",  
export HADOOP_SECONDARYNAMENODE_OPTS="-XX:UseNUMA -Dcom.sun.management.jmxremote $HADOOP_SECONDARYNAMENODE_OPTS", etc.  

But the ratio between local and remote memory access is 2:1, just remains as same as before.

Then we find that hadoop MapReduce start child JVM processes to run task in containers. So we passes -XX:UseNUMA to JVMs by set theting configuration parameter child.java.opts. But hadoop starts to throw ExitCodeExceptionException (exitCode=1), seems that hadoop does not support this JVM parameter.

What should we do to enable UseNUMA flag for my hadoop? Or what should we do to decrease the local/remote memory access in NUMA framework? Should we just change Hadoop script or resorts to source code? And how to do it?

The hadoop version is 2.6.0.

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Failing this attempt.. 
Failing the application.
...