Steps to start db2 console.
create a vncsession and go into the graphical console.
[~]$ xhost +
access control disabled, clients can connect from any host
[~]$ sudo su - root
[~]# cat /etc/passwd | grep db2
db2inst1:x:503:105::/home/db2inst1:/bin/bash
db2inst2:x:504:106::/home/db2inst2:/bin/bash
[~]# su - db2inst2
[~]$ db2cc