PyGrub

Description

PyGrub enables you to start Linux DomUs with the kernels that lie in the filesystem of the DomU instead of with a Kernel that lies in the filesystem of the Dom0. This enables easier kernel update from DomU.

Example Template Preparation

These examples were taken from sources across the internet. Both of these examples worked for us, however they have only been tested in our development environment and we can't guarantee they will work for you.

CentOS

Inside the CentOS domU (Virtual Server)

yum install kernel-xen grub -y
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

Thats it! the vps is set to use it's own kernel.

Debian

Inside the Debian domU (Virtual Server)

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

In domU's /etc/inittab you should look for the line with "xvc0" and just replace the "xvc0" with "hvc0"

Thats it! the vps is set to use it's own kernel.