Name node is in safe mode. Not able to leave

In order to forcefully let the namenode leave safemode, following command should be executed:

 bin/hadoop dfsadmin -safemode leave

You are getting Unknown command error for your command as -safemode isn't a sub-command for hadoop fs, but it is of hadoop dfsadmin.

Also after the above command, I would suggest you to once run hadoop fsck so that any inconsistencies crept in the hdfs might be sorted out.

Update:

Use hdfs command instead of hadoop command for newer distributions. The hadoop command is being deprecated:

hdfs dfsadmin -safemode leave

hadoop dfsadmin has been deprecated and so is hadoop fs command, all hdfs related tasks are being moved to a separate command hdfs.

try this, it will work

sudo -u hdfs hdfs dfsadmin -safemode leave

The Command did not work for me but the following did

hdfs dfsadmin -safemode leave

I used the hdfs command instead of the hadoop command.

Check out http://ask.gopivotal.com/hc/en-us/articles/200933026-HDFS-goes-into-readonly-mode-and-errors-out-with-Name-node-is-in-safe-mode- link too

safe mode on means (HDFS is in READ only mode)
safe mode off means (HDFS is in Writeable and readable mode)

In Hadoop 2.6.0, we can check the status of name node with help of the below commands:

TO CHECK THE name node status

$ hdfs dfsadmin -safemode get

TO ENTER IN SAFE MODE:

$ hdfs dfsadmin -safemode enter

TO LEAVE SAFE mode

~$ hdfs dfsadmin -safemode leave