Disconnected: No supported authentication methods available (server sent publickey, gssapi-keyex gssapi-with-mic)

Disconnected: No supported authentication methods available (server sent publickey, gssapi-keyex gssapi-with-mic) 

Fix:

uncomment PasswordAuthentication yes
[root@oracle12102 ~]# cat /etc/ssh/sshd_config |grep -i Pass
# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication yes
:wq
service sshd restart

Changing Hostname

Changing Host name

#hostname
node01.uk.abc.com
#vi /etc/hostname
node02.uk.abc.com
:wq
restart the node
or 
restart :

hostname
node02.uk.abc.com