Working with Hadoop

Requirement

• Virtual machine software – VM Ware– VirtualBox

• Virtual machine images– Download from Cloudera (Founded by leaders in the field, including father of Hadoop)

Start the Virtual Machine

Inside the Virtual machine

•CentOS 6.4•JDK•Hadoop 2.5.0•Eclipse 4.2.6 (Juno)

Basics of HDFS (routine)

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• With Terminal– hadoop– hadoop version– hadoop jar– hadoop fs …– hadoop fs -ls : List all file in HDFS– hadoop fs –put / -get / -mkdir / -rmdir...

Copy Files from Windows to VM

• WinSCP (see Demo at bin\scp_ssh\winscp575)– Protocol scp– Hostname (Get from ifconfig in Terminal)– Username/Passoword = cloudera/cloudera

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Copy Files from VM (CentOS) to HDFS

• hadoop fs -put localfiles /user/cloudera

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Copy Files from Windows to HDFS

• Via HUE services

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Using web server – port 8888 (File manager)

Hadoop Administration

• http://hostname:50070/dfshealth.html#tab-overview

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WordCount Example in HadoopWordCount Example in Hadoop

• #1: Via guidelines in Cloudera website• #2: Directly in Eclipse (Preferred)

WordCount in Cloudera Website

• http://www.cloudera.com/content/cloudera/en/documentation/hadoop-tutorial/CDH5/Hadoop-Tutorial/ht_wordcount1.html

• Source code downloaded from http://tiny.cloudera.com/hadoopTutorialSample

• Source code details and explanations: http://www.cloudera.com/content/cloudera/en/documentation/hadoop-tutorial/CDH5/Hadoop-Tutorial/ht_wordcount1_source.html

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WordCount in Cloudera Website

• Create directory in HDFS– $ hadoop fs -mkdir /user/cloudera – $ hadoop fs -chown cloudera /user/cloudera– $ hadoop fs -mkdir /user/cloudera/wordcount

/user/cloudera/wordcount/input• Create sample text

– 1: Directly in CentOS $$ echo "Hadoop is an elephant" > file0 $ echo "Hadoop is as yellow as can be" > file1 $ echo "Oh what a yellow fellow is Hadoop" > file2And then move to HDFS$ hadoop fs -put file* /user/cloudera/wordcount/input– 2: Create in Windows and Copy to HDFS via HUE

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WordCount in Cloudera Website

• Compilation error

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WordCount Example in HadoopWordCount Example in Hadoop

• #1: Via guidelines in Cloudera website• #2: Directly in Eclipse (Preferred)

WordCount in Eclipse environment

• http://kishorer.in/2014/10/22/running-a-wordcount-mapreduce-example-in-hadoop-2-4-1-single-node-cluster-in-ubuntu-14-04-64-bit/

• https://www.youtube.com/watch?v=hJsaChh2Yhk (Some parts are different for ClouderaVM)

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Update source codes (from website)

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Adding JAR files to Project

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usr/lib/hadoop; usr/lib/hadoop/lib;usr/lib/hadoop-mapreduce; usr/lib/hadoop-mapreduce/lib

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Run ConfigRun Run Configurations

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File Export

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Update Properties in jar file

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Prepare for run

• Make HDFS directory

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Copy sample input to HDFS (via HUE)

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Run the example (in .jar folder)(Make sure to remove output folder before

use)

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View the result

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Other sources

• Very nice example @ https://hadoop.apache.org/docs/r1.2.1/mapred_tutorial.html

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