Namenode not starting

I was using Hadoop in a pseudo-distributed mode and everything was working fine. But when I restarted my computer I can’t start Namenode. Only way I can start Namenode is by formatting it and I end up losing data in HDFS.

  • Make following changes to start Namenode 

In conf/hdfs-site.xml, you should have a property like





The property “” allow you to control where Hadoop writes NameNode metadata. And giving it another dir rather than /tmp makes sure the NameNode data isn’t being deleted when you reboot.

Format Namenode after you change it

$ bin/hadoop namenode -format

$ bin/hadoop



2 thoughts on “Namenode not starting

  1. shrijeet says:

    using the root login use the command $ iptables -F

    This has got something to do with the routing of the ports…this will solve the issue.


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