Inside the Debian VPS run this:
aptitude install linux-image-2.6-xen-amd64 grub
mkdir /boot/grub
echo "(hd0) /dev/sda" > /boot/grub/device.map
mknod /dev/sda b 202 0
update-grub
That's it...
You can have your own kernel now.
Inside the CentOS VPS run:
yum install kernel-xen grub
ln -s /boot/grub/grub.conf /boot/grub/menu.lst
Once thats done you need to check the menu.lst and make sure it matches the kernel files inside /boot:
#ls -l /boot
total 7276
-rw-r--r-- 1 root root 1209395 Jul 1 20:08 System.map-2.6.18-194.8.1.el5xen
-rw-r--r-- 1 root root 66552 Jul 1 20:08 config-2.6.18-194.8.1.el5xen
drwxr-xr-x 2 root root 4096 Jul 14 10:39 grub
-rw------- 1 root root 2495715 Jul 14 10:38 initrd-2.6.18-194.8.1.el5xen.img
-rw-r--r-- 1 root root 80032 Mar 16 2009 message
-rw-r--r-- 1 root root 112259 Jul 1 20:09 symvers-2.6.18-194.8.1.el5xen.gz
-rw-r--r-- 1 root root 2047941 Jul 1 20:08 vmlinuz-2.6.18-194.8.1.el5xen
-rwxr-xr-x 1 root root 969816 Jul 1 20:56 xen-syms-2.6.18-194.8.1.el5
-rw-r--r-- 1 root root 417433 Jul 1 18:58 xen.gz-2.6.18-194.8.1.el5
#cat /boot/grub/menu.lst
default=0
timeout=10
title vmlinuz-2.6.18-194.8.1.el5xen
root (hd0,1)
kernel /boot/vmlinuz-2.6.18-194.8.1.el5xen console=xvc0 root=/dev/sda1 ro
initrd /boot/initrd-2.6.18-194.8.1.el5xen.img
Ready to go.....
Source: http://wiki.solusvm.com/index.php/PyGrub
