Obligatory Disclaimers
- pv-grub is an advanced feature. It should only be used by experienced Linux administrators with a demonstrated need to run their own kernels.
- This is only necessary for older First-Generation servers that do not already include the kernel inside the instance. If you already have a kernel in /boot, it is likely your instance does not need to be modified to use pv-grub.
- Not all kernels are supported. Your kernel must have pv-ops support for running in a Xen domU. Also, kernels compressed with bzip or LZMA will not work, and for some distributions like Arch compressed kernels may not work at all.
- Follow the instructions as listed, in the order listed. Do not blindly copy/paste these commands, as some of them will require editing.
- Do not attempt these instructions on a production system. If they are applied incorrectly, your Cloud Server may become unbootable. Practice on a clone of your server first.
- This process is only compatible with the original version of GRUB, also referred to as GRUB Legacy. Our base images should only include GRUB Legacy, but a system update might install a newer version of GRUB (GRUB2) and need to be reverted to GRUB Legacy before this process will work.
Grub configuration
Every instance booted with pv-grub requires a working grub configuration file in /boot/grub/menu.lst:
default=0
timeout=5
title=DISTRO-NAME "KERNEL VERSION STRING"
root (hd0)
kernel /boot/KERNEL-VMLINUZ-FILENAME ro console=hvc0 root=/dev/xvda1
initrd /boot/KERNEL-INITRD-FILENAME
Distribution-specific adjustments
Arch
pacman -Sy pacman pacman -Sy base-devel pacman -Syu sed -i 's/sda/xvda/' /etc/fstab pacman -Sy kernel26 mkdir -p /boot/grub cp /usr/src/KERNEL-VERSION/vmlinux /boot/vmlinux26
Note: The stock arch kernel is bzipped and won’t work with pv-grub. Use the uncompressed vmlinux instead.
Now add (or uncomment) the following line in /etc/inittab for console:
h0:2345:respawn:/sbin/agetty -8 38400 hvc0 linux
CentOS 5.x
yum -y upgrade mkdir -p /boot/grub echo "alias eth0 xennet" > /etc/modprobe.conf echo "alias eth1 xennet" >> /etc/modprobe.conf echo "alias scsi_hostadapter xenblk" >> /etc/modprobe.conf echo "xvc0" >> /etc/securetty sed -i 's/sda/xvda/' /etc/fstab yum -y install kernel-xen
Now add (or uncomment) the following line in /etc/inittab for console:
8:2345:respawn:/sbin/mingetty xvc0
Debian 5.x
apt-get update; apt-get -y upgrade mkdir /boot/grub sed -i 's/sda/xvda/' /etc/fstab apt-get -y install linux-image-xen-amd64
Now add (or uncomment) the following line in /etc/inittab for console:
8:2345:respawn:/sbin/getty 38400 hvc0
Fedora 13
mkdir -p /boot/grub echo "alias eth0 xennet" > /etc/modules echo "alias eth1 xennet" >> /etc/modules echo "alias scsi_hostadapter xenblk" >> /etc/modules sed -i 's/sda/xvda/' /etc/fstab echo "hvc0" >> /etc/securetty yum -y install kernel
Gentoo
emerge --sync emerge --update portage emerge gentoo-sources genkernel #Update /usr/src/linux symlink if necessary sudo sed -i 's/sda/xvda/' /etc/fstab genkernel --menuconfig all
Enable the following in the kernel configuration:
Processor Type and Features -> Paravirtualized guest support -> "Y" Hit enter, go to "Xen guest support" -> "Y"
Then exit the configuration, save, and build.
Now add (or uncomment) the following line in /etc/inittab for console:
h0:12345:respawn:/sbin/agetty 38400 hvc0 linux
RHEL 5.x
yum -y upgrade mkdir -p /boot/grub echo "alias eth0 xennet" > /etc/modprobe.conf echo "alias eth1 xennet" >> /etc/modprobe.conf echo "alias scsi_hostadapter xenblk" >> /etc/modprobe.conf echo "xvc0" >> /etc/securetty sed -i 's/sda/xvda/' /etc/fstab yum -y install kernel-xen
Now add (or uncomment) the following line in /etc/inittab for console:
8:2345:respawn:/sbin/mingetty xvc0
Ubuntu 9.10/10.04
mkdir /boot/grub cp /etc/init/tty1.conf /etc/init/hvc0.conf sed -i 's/tty1/hvc0/' /etc/init/hvc0.conf sed -i 's/sda/xvda/' /etc/fstab apt-get -y install linux-virtual
Ubuntu 10.10
mkdir /boot/grub cp /etc/init/tty1.conf /etc/init/hvc0.conf sed -i 's/tty1/hvc0/' /etc/init/hvc0.conf apt-get -y install linux-virtual
Kernel upgrade
Contact Rackspace Cloud support and request the pv-grub feature, informing them that you have completed these steps and would like to use your own kernel. Your Cloud Server will be rebooted, and — if all goes well — will come back up with your new kernel. You may verify this with ‘uname -a’.