Converting Xen CFG to libvirt XML

In previous betas of unRAID 6, users made use of the xl toolset from Xen to create and control virtual machines.  In Beta 6d, while the xl toolset remains, a new and preferred method to VM management has been introduced:  libvirt.  Libvirt is a set of tools that are used to create and control virtual machines under both the Xen and KVM hypervisor.    For those that have upgraded to beta 6d from a previous unRAID 6 beta that included Xen, you should already be comfortable defining your VMs through a .cfg file.  If you wish to continue using this method for your existing VMs, you still can.  However, the process of converting an domain's xl cfg file to the XML format used by libvirt isn't overly challenging.  Here's an example for converting an existing xl cfg file for a domain into libvirt's XML format:

 

Domain CFG File

name="win7-v1"
builder="hvm"

vcpus=2
memory=2048
disk=['file:/path/to/virtual/disk.img,hda,w']
vif=['mac=00:00:00:01:34:12,bridge=xenbr0']
boot="dc"

vnc=1
vnclisten='0.0.0.0'
vncpasswd=''

#NO USB PASSTHROUGH DEVICES, USE THIS
usb=1
usbdevice='tablet'  

on_poweroff="destroy"
on_reboot="restart"
on_crash="destroy"

xen_platform_pci=1
viridian=1

 

Domain XML File

<domain type='xen' id='3'>
  <name>win7-v1</name>
  <uuid>4dea22b31d52d8f32516782e98ab3fa0</uuid>
  <os>
    <type>hvm</type>
    <loader>/usr/lib/xen/boot/hvmloader</loader>
    <boot dev='hd'/>
  </os>
  <memory>2097152</memory>
  <vcpu>2</vcpu>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <features>
    <pae/>
    <acpi/>
    <apic/>
  </features>
  <clock sync="localtime"/>
  <devices>
    <emulator>/usr/bin/qemu-system-x86_64</emulator>
    <interface type='bridge'>
      <source bridge='xenbr0'/>
      <mac address='00:16:3e:5d:c7:9e'/>
      <script path='vif-bridge'/>
    </interface>
    <disk type='file'>
      <source file='/path/to/virtual/disk.img'/>
      <target dev='hda'/>
    </disk>
    <graphics type='vnc' port='5900'>
      <listen type='address' address='0.0.0.0'/>
    </graphics>
  </devices>
</domain>

 

For more information on creating XML files for Xen using libvirt's virsh tool, check out this link:  http://libvirt.org/drvxen.html

 

Thanks JonP - how does one comment out lines in the XML?

 

IE

# Disable Passthrough for Driver updates and any Windows update requiring a restart.
# Use TightVNC Java Viewer with RAW encoding to Update (port: 5901).  IP check in unraid terminal: ifconfig.

name = 'windows'
builder = 'hvm'
vcpus = '2' #can set this to 1-4 safely depending on your CPU/# of VMs.
memory = '2048'  #DO NOT EXCEED UNLESS BRAVE IF DOING GPU PASS THROUGH
#memory = '8192'

#----For Disc Installation and any Updates (VNC into Windows)
#disk = ['phy:/mnt/cache/VM/windows/windows.img,hda,w','file:/mnt/cache/VM/windows/Windows81_DVD.iso,hdc:cdrom,r']
#boot = 'dc'
#usbdevice='tablet'

#----After Installation and for GPU Passthrough
disk = ['phy:/mnt/cache/VM/windows/windows.img,hda,w']
boot = 'c'
usbdevice = ['tablet','host:413c:3016','host:413c:2005','host:05e3:0719'] #LOOK UP VIA lsusb COMMAND IN CONSOLE
pci = [ '01:00.0','01:00.1','05:00.0','05:00.1','05:00.2' ] #LOOK UP VIA lspci COMMAND IN CONSOLE
#Prior to Start VIA xl pci-assignable-list COMMAND IN CONSOLE to show list of excluded from unRaid PCI devices. 
#Note, after starting VM, Putty into Tower2 and issue "xl pci-attach windows 0000:05:02.0" to mount the Sata Card / Optical Disk Drive

#---Other Settings
xen_platform_pci='1' #UNCOMMENT POST INSTALL OF XEN PARAVIRTUALIZATION DRIVERS

on_poweroff="destroy"
on_reboot="restart"
on_crash="destroy"

vif = ['mac=00:16:3E:51:20:4C,bridge=br0,model=e1000'] #network bridge

device_model_version="qemu-xen-traditional"
acpi = '1'
apic = '1'
sdl = '0'
stdvga = '0'
viridian = '1'
usb=1

#VNC SETTINGS
vnc = '1'
vnclisten = '0.0.0.0'
#vncpasswd = ''
vncdisplay = 1
__

 

XML comments are achieved by using this:

 

<!-- INSERT COMMENT HERE -->

XML comments are achieved by using this:

 

<!-- INSERT COMMENT HERE -->

 

Fantastic.  Thanks!

How about passthrough? How would one state this in libvirt xml format?

 

Sent from my LT26i using Tapatalk

 

 

You define it like this;

 

#pci = [ '01:00.0','01:00.1' ] #LOOK UP VIA lspci COMMAND IN CONSOLE

 

1. ssh to domU/unraid server, run "lspci" should look something like this (its a bigger list) ;

 

01:00.0 VGA compatible controller: AMD/ATI [Advanced Micro Devices, Inc.] Caicos [Radeon HD 6450]
01:00.1 Audio device: AMD/ATI [Advanced Micro Devices, Inc.] Caicos HDMI Audio [Radeon HD 6400 Series]

 

2. pick the pci adresses you need and write them down. Let us use 01:00.0 as your gpu (and 01:00.1 as hdmi audio device) in this example, it will most likely not be the same on your machine.

3. then

cd /boot/syslinux/

4. then

mcedit syslinux.cfg

5. insert this into bottom of file;

 

label Xen/unRAID Passthrough # <- text in boot menu
menu default
  kernel /syslinux/mboot.c32
  append /xen dom0_mem=2097152 --- /bzimage xen-pciback.hide=(01:00.0)(01:00.1) --- /bzroot

 

6. its imperative that you remove any other line with "menu default" from the already existing config file, as this will then be your default os-boot options.

7. the lines above will make unraid ignore the devices 01:00.0 and 01:00.1 and will not assign them to unraid making them available for a virtual guest machine.

8. when you have booted, do the following command:

xl pci-assignable-list 

9. you should see 01:00.0 and 01:00.1 in this list, if you do, the devices are ready to be passed through to your VM.

 

Remember, you have to install and update the virtual machine first via VNC. When this is done, install the AMD/ATI drivers without (extremely important) Catalyst Control Center (CCC). Just deselect it in the installer (select custom install in the installer). Your VM might crash (or not), dont worry about it.

Go to your VM config file, edit the line in your config file to this;

 

pci = [ '01:00.0','01:00.1' ]

 

Start your VM. Expect to have a few bsod's etc.

You're trying to passthrough an NVIDIA card? sorry m8, can't help you. Although, AMD/ATI cards works a lot better for passthrough.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Is this the config file format for KVM? (ie, can I do this config file conversion and then launch my image file in KVM?)

 

Also, what's the KVM equivalent of xen-pciback.hide for hiding passthrough devices?

 

Thanks