Hadoop Not able to start Namenode

Question

I try to start the name node server, it shows error like below

13/05/23 04:11:37 ERROR namenode.FSNamesystem: FSNamesystem initialization failed.
java.io.IOException: NameNode is not formatted.
        at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:330)
        at org.apache.hadoop.hdfs.server.namenode.FSDirectory.loadFSImage(FSDirectory.java:100)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.initialize(FSNamesystem.java:411)

How to solve this?

Answer 1

Stop all running server

1) stop-all.sh 

Edit the file /usr/local/hadoop/conf/hdfs-site.xml and add below configuration if its missing

<property>
    <name>dfs.data.dir</name>
    <value>/app/hadoop/tmp/dfs/name/data</value> 
    <final>true</final> 
    </property> 
    <property> 
    <name>dfs.name.dir</name>
    <value>/app/hadoop/tmp/dfs/name</value> 
    <final>true</final> 
</property>

Start both HDFS and MapReduce Daemons

2) start-dfs.sh
3) start-mapred.sh

This should work