Create Alpine Linux PV DomU
Obtain a copy of Alpine Linux
To create an Alpine Linux paravirtualized (PV) DomU you'll need an Alpine Linux iso.
Download the latest alpine-virt iso from https://alpinelinux.org/downloads/
In this example we'll use /data/ for the download and disk images.
Mount the ISO image
Next, mount the iso so you can read the kernel and initramfs:
mount -t iso9660 -o loop /data/alpine-virt-3.21.0-x86_64.iso /media/cdrom
Now you have the kernel in /media/cdrom/boot/vmlinuz-virt and initramfs in /media/cdrom/boot/initramfs-virt.
Alternatively you can use uniso or 7z to extract the content to a temporary area.
Create the disk image
Now you need to create an empty file to be used as the hard drive of the DomU (in this example we are using a 3GB disk):
dd if=/dev/zero of=/data/a1.img bs=1M count=3000
Alternatively, if an LVM volume group (e.g. vg1) with free space is available on dom0, create a logical volume for Alpine:
sudo lvcreate -n alpine -L 10g vg1
Create a DomU config file that boots the ISO image
Next, create a basic DomU configuration file, so you can launch the pv guest iso (save it where you like, although the most common place is /etc/xen/).
Contents of /etc/xen/a1.cfg
If using LVM, replace /data/a1.img with /dev/vg1/alpine in the disk specification.
Install the guest
Now that you have the necessary files, you can start the DomU to proceed with the install:
xl create -f /etc/xen/a1.cfg -c
Log into the system with user "root" and no password.
After configuring the basic system, you will be asked where would you like to install Alpine. Choose xvda and sys.
That will create three partitions on your disk. xvda1 for /boot, xvda2 for swap and xvda3 for /
Available disks are:
xvda (3.1 GB )
Which disk(s) would you like to use? (or '?' for help or 'none') [none] xvda
The following disk is selected:
xvda (3.1 GB )
How would you like to use it? ('sys', 'data' or '?' for help) [?] sys
WARNING: The following disk(s) will be erased:
xvda (3.1 GB )
WARNING: Erase the above disk(s) and continue? [y/N]: y
Initializing partitions on /dev/xvda...
Creating file systems...
Installing system on /dev/xvda3:
Installation is complete. Please reboot.
#
When you reboot, the pv bootloader pvgrub, will look to /boot/grub/grub.cfg for its menu, so create that file first.
Mount the boot partition and create a grub/grub.cfg file for pvgrub. (Note that grub.cfg is for pvgrub2 which replaced pvgrub1 and its menu.lst beginning in 2013.)
mount /dev/xvda1 /mnt mkdir /mnt/grub
Install a basic text editor like nano or vim:
apk add nano
If using nano, enter:
nano /mnt/grub/grub.cfg
Then add the following to create a basic grub2 configuration file:
Contents of /mnt/grub/grub.cfg
Finally, Ctrl-S to save, Ctrl-X to exit nano.
Unmount and power off.
umount /mnt poweroff
Adjust the domU config file to boot from fresh install
In your Dom0, edit your DomU config file to boot with pvgrub.
Contents of /etc/xen/a1.cfg
Make sure that grub-xenhost is installed.
apk add grub-xenhost
Remember to unmount the loopback iso image.
umount /media/cdrom
The next time you boot, you'll be presented with the grub boot menu, and your VM will boot.
Using Legacy pvgrub
To use Legacy pvgrub you need to use a /boot/grub/menu.lst instead of /boot/grub/grub.cfg.
Contents of /etc/xen/a1.cfg
And in /etc/xen/a1.cfg you need to change the 'kernel' loader to
Contents of /etc/xen/a1.cfg