ERROR: A different toolstack (xm) have been selected!

ERROR:  A different toolstack (xm) have been selected!

Earlier I have worked with xm - Xen Management tool - built in Python.
I thought of using xl Stack. So When I issued the command,

xl

I got the error

ERROR:  A different toolstack (xm) have been selected!

We shall select a Stack either xm or xl. We need to mention in this file

/etc/default/xen

If,

TOOLSTACK=xl

Means We have choosen xl stack

If ,

TOOLSTACK=xm

Means We have chosen xm commands.

Refer:

http://www.gossamer-threads.com/lists/xen/users/234948