Create Alpine Linux PV DomU

Obtain a copy of Alpine Linux

To create an Alpine Linux paravirtualized (PV) DomU you will need an Alpine Linux iso.

Download the latest and greatest iso

Download Stable Version Alpine 3.20.3

Extract the xen-aware linux kernel

Next, mount the iso and extract the kernel and initramfs:

# mkdir -p /mnt/alpine_iso
# mount -t iso9660 -o loop /path/to/the/iso /mnt/alpine_iso
# cp /mnt/alpine_iso/boot/grsec /path/to/save/kernel/
# cp /mnt/alpine_iso/boot/grsec.gz /path/to/save/kernel/
# umount /mnt/alpine_iso
# rmdir /mnt/alpine_iso

Now we have the kernel in /path/to/save/kernel/grsec and initramfs in /path/to/save/kernel/grsec.gz.

Create the disk image

Now we should create an empty file, that will be the hard drive of the DomU (in this example we are using a 3GB disk):

# dd if=/dev/zero of=/path/to/disk.img bs=1M count=3000

Create a DomU config file that boots the ISO image

The next step is to create a basic DomU configuration file, so we can launch the pv guest iso (save it where you like, although the most common place is /etc/xen/).

# Alpine Linux PV DomU

# Kernel paths for install
kernel = "/path/to/save/kernel/grsec"
ramdisk = "/path/to/save/kernel/grsec.gz"
extra="alpine_dev=xvdc:iso9660 modules=loop,squashfs,sd-mod,usb-storage modloop=/boot/grsec.modloop.squashfs console=hvc0"

# Path to HDD and iso file
disk = [
        'format=raw, vdev=xvda, access=w, target=/path/to/disk.img',
        'format=raw, vdev=xvdc, access=r, devtype=cdrom, target=/path/to/the/iso'
       ]

# Network configuration
vif = ['bridge=br0']

# DomU settings
memory = 512
name = "alpine"
vcpus = 1
maxvcpus = 1

Install the guest

Now that we have all the necessary files, we can start the DomU to proceed with the install:

# xl create -f /path/to/conf -c

Login into the system with user "root" and no password, and proceed with the normal install:

# setup-alpine

After configuring the basic system, you will be asked where would you like to install Alpine, choose xvda and sys.

This 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.

# halt

Adjust the domU config file to boot from fresh install

In your Dom0, edit your DomU config file to boot from the fresh install

# Alpine Linux PV DomU

# Kernel paths for install
kernel = "/path/to/save/kernel/grsec"
ramdisk = "/path/to/save/kernel/grsec.gz"
extra="modules=sd-mod,usb-storage,ext4,squashfs console=hvc0 root=/dev/xvda3"


# Path to HDD and iso file
disk = [
        'format=raw, vdev=xvda, access=w, target=/path/to/disk.img'
       ]

# Network configuration
vif = ['bridge=br0']

# DomU settings
memory = 512
name = "alpine"
vcpus = 1
maxvcpus = 1

Adding a grub config file to boot with pvgrub

Now boot the VM once more to add a grub config file so that we may load the xen-aware kernel from within the VM.

This means that upgrading the kernel will not mean copying it to the dom0.

# xl create -f /path/to/conf -c

Log in as root and create the file /boot/grub/menu.lst with the following content

#/boot/grub/menu.lst

default 0
timeout 5
 
title alpine-xen-pv
	root (hd0,0)
	kernel /boot/vmlinuz-grsec modules=sd-mod,usb-storage,ext4,squashfs console=hvc0 root=/dev/xvda3
	initrd /boot/initramfs-grsec 

Halt your VM one last time

# halt

Adjust the DomU config file one last time to use pvgrub

Your final xen DomU config file should look something like this.

# Alpine Linux PV DomU
disk = [
        'format=raw, vdev=xvda, access=w, target=/path/to/alpine.img'
        ]

kernel = "/usr/lib/xen/boot/pv-grub-x86_64.gz"

vif = [ 'bridge=br0' ]
memory = 1024
name = "alpine"
vcpus = 1
maxvcpus = 1

When you next boot, you will be presented with the grub boot menu, and your VM will boot.