Hadoop SSH asking for password

If once you have setup SSH properly and you see that hadoop is again asking for password while SSH connection then you need to do following

$ chmod go-w $HOME $HOME/.ssh
$ chmod 600 $HOME/.ssh/authorized_keys
$ chown `whoami` $HOME/.ssh/authorized_keys

For detailed instructions on SSH setup for Hadoop , please read this post below

http://allthingshadoop.com/2010/04/20/hadoop-cluster-setup-ssh-key-authentication/