Create Alpine Linux PV DomU: Difference between revisions

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To create an Alpine Linux PV DomU you will need an Alpine Linux iso.
== Obtain a copy of Alpine Linux ==


Download the latest and greatest iso from the [http://alpinelinux.org/ Alpine Linux] website.
To create an Alpine Linux paravirtualized (PV) DomU you'll need an Alpine Linux iso.


== Extract the xen-aware linux kernel ==
Download the latest alpine-virt iso from https://alpinelinux.org/downloads/


Next, mount the iso and extract the kernel and initramfs:
In this example we'll use {{path|/data/}} for the download and disk images.


<pre>
==Mount the ISO image ==
# mkdir -p /mnt/alpine_iso
 
# mount -o loop /path/to/the/iso /mnt/alpine_iso
Next, mount the iso so you can read the kernel and initramfs:
# cp /mnt/alpine_iso/boot/grsec /path/to/save/kernel/
 
# cp /mnt/alpine_iso/boot/grsec.gz /path/to/save/kernel/
{{cmd | mount -t iso9660 -o loop /data/alpine-virt-{{AlpineLatest}}-x86_64.iso /media/cdrom }}
# umount /mnt/alpine_iso
 
# rmdir /mnt/alpine_iso
Now you have the kernel in {{path|/media/cdrom/boot/vmlinuz-virt}} and initramfs in {{path|/media/cdrom/boot/initramfs-virt}}.
</pre>


Now we have the kernel in /path/to/save/kernel/grsec and initramfs in /path/to/save/kernel/grsec.gz.
Alternatively you can use {{path|uniso}} or {{path|7z}} to extract the content to a temporary area.


== Create the disk image ==
== 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):
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):


<pre>
{{cmd | <nowiki>dd if=/dev/zero of=/data/a1.img bs=1M count=3000</nowiki>}}
# dd if=/dev/zero of=/path/to/disk.img bs=1M count=3000
 
</pre>
Alternatively, if an LVM volume group (e.g. vg1) with free space is available on dom0, create a logical volume for Alpine:
 
{{cmd | <nowiki>sudo lvcreate -n alpine -L 10g vg1</nowiki>}}


== Create a DomU config file that boots the ISO image ==
== 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/).
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 {{path|/etc/xen/}}).


<pre>
{{cat | /etc/xen/a1.cfg | <nowiki># Alpine Linux PV DomU
# Alpine Linux PV DomU


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


# Path to HDD and iso file
# Path to HDD and iso file
disk = [
disk = [
         'format=raw, vdev=xvda, access=w, target=/path/to/disk.img',
         'format=raw, vdev=xvda, access=w, target=/data/a1.img',
         'format=raw, vdev=xvdc, access=r, devtype=cdrom, target=/path/to/the/iso'
         'format=raw, vdev=xvdc, access=r, devtype=cdrom, target=/data/alpine-virt-</nowiki>{{AlpineLatest}}<nowiki>-x86_64.iso'
       ]
       ]


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# DomU settings
# DomU settings
memory = 512
memory = 512
name = "alpine"
name = "alpine-a1"
vcpus = 1
vcpus = 1
maxvcpus = 1
maxvcpus = 1
</pre>
</nowiki>}}
 
If using LVM, replace {{path|/data/a1.img}} with {{path|/dev/vg1/alpine}} in the disk specification.


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


<pre>
{{cmd|xl create -f /etc/xen/a1.cfg  -c}}
# xl create -f /path/to/conf -c
</pre>


Login into the system with user "root" and no password, and proceed with the normal install:
Log into the system with user "root" and no password.
 
<pre>
# setup-alpine
</pre>


After configuring the basic system, you will be asked where would you like to install Alpine, choose xvda and sys.
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 /
That will create three partitions on your disk. xvda1 for {{path|/boot}}, xvda2 for swap and xvda3 for {{path|/}}


<pre>
<pre>
Line 86: Line 82:
Installation is complete. Please reboot.
Installation is complete. Please reboot.


# halt
#
</pre>
 
When you reboot, the pv bootloader pvgrub, will look to {{path|/boot/grub/grub.cfg}} for its menu, so create that file first.
 
Mount the boot partition and create a {{path|grub/grub.cfg}} file for pvgrub. (Note that grub.cfg is for pvgrub2 which replaced pvgrub1 and its menu.lst beginning in 2013.)
 
{{cmd |<nowiki>mount /dev/xvda1 /mnt
mkdir /mnt/grub</nowiki>}}
 
Install a basic text editor like {{pkg|nano}} or {{pkg|vim}}:<br/>
{{cmd | apk add nano}}
 
If using nano, enter:<br/>
{{cmd | nano /mnt/grub/grub.cfg}}


</pre>
Then add the following to create a basic grub2 configuration file:
{{cat | /mnt/grub/grub.cfg |<nowiki>menuentry 'alpine-xen' {
    set root=(xen/xvda,msdos1)
    linux /boot/vmlinuz-virt root=/dev/xvda3 modules=ext4 console=hvc0
    initrd /boot/initramfs
}</nowiki>}}


== Adjust the domU config file to boot from fresh install ==
Finally, Ctrl-S to save, Ctrl-X to exit nano.


In your Dom0, edit your DomU config file to boot from the fresh install
Unmount and power off.
{{cmd |umount /mnt
poweroff}}


== Adjust the domU config file to boot from fresh install ==


<pre>
In your Dom0, edit your DomU config file to boot with pvgrub.
# Alpine Linux PV DomU


# Kernel paths for install
{{cat | /etc/xen/a1.cfg |<nowiki># Alpine Linux PV DomU
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"


kernel = "/usr/lib/grub-xen/grub-x86_64-xen.bin"


# Path to HDD and iso file
# Path to HDD and iso file
disk = [
disk = [
         'format=raw, vdev=xvda, access=w, target=/path/to/disk.img'
         'format=raw, vdev=xvda, access=w, target=/data/a1.img'
       ]
       ]


Line 114: Line 129:
# DomU settings
# DomU settings
memory = 512
memory = 512
name = "alpine"
name = "alpine-a1"
vcpus = 1
vcpus = 1
maxvcpus = 1
maxvcpus = 1
</pre>
</nowiki>}}


==Adding a grub config file to boot with pvgrub==
Make sure that grub-xenhost is installed.
{{cmd | apk add grub-xenhost}}


Now boot the VM once more to add a grub.conf file so that we may load the xen-aware kernel from within the VM.
Remember to unmount the loopback iso image.
{{cmd | umount /media/cdrom}}


This means that upgrading the kernel will not mean copying it to the dom0.
The next time you boot, you'll be presented with the grub boot menu, and your VM will boot.


<pre>
== Using Legacy pvgrub ==
# xl create -f /path/to/conf -c
</pre>


Log in as root and create the file /boot/grub.conf with the following content
To use Legacy pvgrub you need to use a {{path|/boot/grub/menu.lst}} instead of {{path|/boot/grub/grub.cfg}}.


<pre>
{{cat | /etc/xen/a1.cfg |<nowiki>default 0
 
timeout 2
#/boot/grub.conf
 
default 0
timeout 5
title alpine-xen-pv
title alpine-xen-pv
root (hd0,0)
root (hd0,0)
kernel /boot/grsec modules=sd-mod,usb-storage,ext4,squashfs console=hvc0 root=/dev/xvda3
kernel /boot/vmlinuz-virt root=/dev/xvda3 modules=ext4 console=hvc0
initrd /boot/grsec.gz
initrd /boot/initramfs-virt
 
</nowiki>}}
</pre>
 
Halt your VM one last time
 
<pre>
# halt
</pre>
 
==Adjust the DomU config file one last time to use pvgrub==
 
Your final xen DomU config file should look something like this.
 
<pre>
# Alpine Linux PV DomU
disk = [
        'format=raw, vdev=xvda, access=w, target=/path/to/alpine.img'
        ]


And in {{path|/etc/xen/a1.cfg}} you need to change the 'kernel' loader to
{{cat | /etc/xen/a1.cfg |<nowiki>...
kernel = "/usr/lib/xen/boot/pv-grub-x86_64.gz"
kernel = "/usr/lib/xen/boot/pv-grub-x86_64.gz"
extra="(hd0,0)/boot/grub.conf"
...
 
</nowiki>}}
vif = [ 'bridge=br0' ]
memory = 1024
name = "alpine"
vcpus = 1
maxvcpus = 1
 
</pre>


When you next boot, you will be presented with the grub boot menu, and your VM will boot.
== See also ==
* [https://www.linkedin.com/pulse/setting-up-alpine-linux-370-domu-vm-xenserver-72-ali-poursamadi Setting up Alpine Linux 3.7.0 as a domU VM on XenServer 7.2]


[[Category:Virtualization]]
[[Category:Virtualization]]

Latest revision as of 20:02, 18 August 2023

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-3.20.3-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

# Alpine Linux PV DomU # Kernel paths for install kernel = "/media/cdrom/boot/vmlinuz-virt" ramdisk = "/media/cdrom/boot/initramfs-virt" extra="modules=loop,squashfs console=hvc0" # Path to HDD and iso file disk = [ 'format=raw, vdev=xvda, access=w, target=/data/a1.img', 'format=raw, vdev=xvdc, access=r, devtype=cdrom, target=/data/alpine-virt-3.20.3-x86_64.iso' ] # Network configuration vif = ['bridge=br0'] # DomU settings memory = 512 name = "alpine-a1" vcpus = 1 maxvcpus = 1

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

menuentry 'alpine-xen' { set root=(xen/xvda,msdos1) linux /boot/vmlinuz-virt root=/dev/xvda3 modules=ext4 console=hvc0 initrd /boot/initramfs }

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

# Alpine Linux PV DomU kernel = "/usr/lib/grub-xen/grub-x86_64-xen.bin" # Path to HDD and iso file disk = [ 'format=raw, vdev=xvda, access=w, target=/data/a1.img' ] # Network configuration vif = ['bridge=br0'] # DomU settings memory = 512 name = "alpine-a1" vcpus = 1 maxvcpus = 1

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

default 0 timeout 2 title alpine-xen-pv root (hd0,0) kernel /boot/vmlinuz-virt root=/dev/xvda3 modules=ext4 console=hvc0 initrd /boot/initramfs-virt

And in /etc/xen/a1.cfg you need to change the 'kernel' loader to

Contents of /etc/xen/a1.cfg

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

See also

Retrieved from "https://wiki.alpinelinux.org/w/index.php?title=Create_Alpine_Linux_PV_DomU&oldid=24370"