Upgrade Hadoop with Latest version - Simple steps

Here i've listed few simple steps to upgrade Hadoop NameNode with out loss of exsiting Data in the cluster.

It's advisable to take backup of Hadoop metadata placed under : dfs.namenode.name.data OR dfs.name.dir dir

Step's

1) stop-yarn.sh


2) stop-dfs.sh

3) Download and configure the latest version of Hadoop

4) cd $HADOOP_PREFIX/etc/hadoop
    in hdfs-site.xml ,
       change the dfs.namenode.name.dir and (if in case of pseudo node) dfs.datanode.data.dir to point to the old version of Hadoop path

5) ./sbin/hadoop-daemon.sh start namenode -upgrade

6) you will see following message in Web UI namenodeIP:50070 "Upgrade in progress. Not yet finalized." and SafeMode is ON

7) ./bin/hdfs dfsadmin -finalizeUpgrade

8) investigate the NameNode log, which should contains this information,

 
Upgradepgrade of local storage directories.
   old LV = -57; old CTime = 0.
   new LV = -57; new CTime = 1417064332016

9) safeMode will go off automatically, once you complete all these..

10) start the DFS
    ./sbin/start-dfs.sh --config $HADOOP_PREFIX/etc/hadoop

11) start the Yarn
    ./sbin/start-yarn.sh --config $HADOOP_PREFIX/etc/hadoop