I have installed Hadoop and SSH on my laptop. \"ssh localhost\" works fine. After formatting HDFS, I tried to start hadoop.
munichong@GrindPad:~$ sudo /usr/
I ran into the same problem. As Amar said,if you are running as sudo hadoop will ask for root password. If you don't have a root password, you can setup one using
sudo passwd
below URL gives you more detail about user management.
https://help.ubuntu.com/12.04/serverguide/user-management.html