org.apache.hadoop.hdfs.server.namenode.SafeModeException: Cannot create directory /user/...../test. Name node is in safe mode.
In order to forcefully let the namenode leave safemode, following command should be executed:
$ bin/hadoop dfsadmin -safemode leave
-safemode isn’t a sub-command for hadoop fs, but it is of hadoop dfsadmin.
Run following command so that any inconsistencies in the hdfs might be sorted out.
$ hadoop fsck
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 “dfs.name.dir” 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 start-all.sh