Set up Hadoop in pseudo distributed mode

Posted By Md Qasim Siddiqui | 28-Dec-2014

Following my previous blog on 'Set up Hadoop on single node', This Blog will explain how to set up hadoop in pseudo-distributed mode

 

  • Configure the core-site.xml,mapred-site.xml and hdfs-site.xml  present in /opt/hadoop-2.5.1/etc/hadoop

  • core-site.xml

 

  	fs.default.name
 	 hdfs://localhost:9000
  	The name of the default file system. A URI whose
  	scheme and authority determine the FileSystem implementation.
  	
  • Hadoop’s default configurations use hadoop.tmp.dir as the base temporary directory both for the local file system and HDFS

  • Change hadoop.tmp.dir property to /app/hadoop/tmp in core-site.xml like this 

 

hadoop.tmp.dir
/app/hadoop/tmp
A base for other temporary directories.


  	fs.default.name
 	 hdfs://localhost:9000
  	The name of the default file system. A URI whose
  	scheme and authority determine the FileSystem implementation.
  	


 
  • mapred-site.xml.template 
 

	mapred.job.tracker
	hostname:8021


 
  • hdfs-site.xml
 

  	dfs.replication
  	1
  	Default block replication.
  	The actual number of replications can be specified when the file is created.
  	The default is used if replication is not specified in create time.
  	
  • Create hadoop tmp directory , sudo mkdir -p /app/hadoop/tmp

  • change ownership permission of tmp in /app/hadoop/tmp to user from root , tmp directory user permission should be same as hadoop directory

  • sudo chown user:user /app/hadoop/tmp

  • Now format the namenode , Type hdfs namenode -format

  • Note: If you forget to set the required ownerships and permissions, you will see a java.io.IOException when you try to format the name node

  • Now start the hadoop services , /opt/hadoop-2.5.1/sbin//start-dfs.sh and /opt/hadoop-2.5.1/sbin//start-yarn.sh

  • The hadoop daemon log output is written to the ${HADOOP_LOG_DIR} directory (defaults to ${HADOOP_HOME}/logs).

  • Type jps, to check all hadoop daemons started successfully

     12882 Jps

12320 SecondaryNameNode

12592 NodeManager

12106 DataNode

11978 NameNode

12468 ResourceManager

Congratz Ur Hadoop installed successfully!

 

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