KVM Hypervisor Setup

# egrep -c '(svm|vmx)' /proc/cpuinfo
 ^ 0 = no support.

# apt update; apt upgrade
# apt install qemu-kvm libvirt-clients libvirt-daemon-system
# usermod myuser -a -G libvirt-qemu,libvirt

(GUI) # apt install xorg
      # apt install --no-install-recommends openbox
      # apt install virt-manager

      ^ Minimal GUI with manual 'startx' control.

# apt-get update; apt-get upgrade
# apt-get install task-lxde-desktop
# apt-get install qemu-kvm libvirt-bin bridge-utils virt-manager
# usermod myuser -a -G kvm,libvirt

	NOTE: While it's preferable to run a hypervisor system as clean as possible,
	      it's nice to have local management available. And it's only about 2 GB.

# virsh autostart vmName
  ^ add --disable at the end to turn autostart off again.

# virsh list --all

# virsh snapshot-list vmName

# virsh shutdown [name|id|uuid]
  ^ use 'destroy' instead of 'shutdown' to power it off instead.
    use 'start' to start it again.
	
# watch virsh list --all
  ^ to monitor state.

# virsh dumpxml [name|id|uuid] > [filename].xml

# virsh define /path/to/[filename].xml
  ^ This will define but not start the machine, edit xml first as needed on new host.

# virsh domblklist vm1
# virsh snapshot-create-as --domain vm1 guest-state1 \
	--diskspec vda,file=/whatever/vm1_temp.qcow2 \
	--disk-only --atomic

Main disk file is now not currently used, back it up.
Let's export the XML configuration as well to make it complete.
# virsh domblklist vm1 (confirm using temporary disk)
# cp /wherever/vm1.qcow2 /wherever_backup/vm1.qcow2
  ^ use whatever tool preferred to copy the file.
# virsh blockcommit vm1 vda --active --verbose --pivot
# virsh domblklist vm1 (confirm back to main disk)
# virsh snapshot-delete vm1 --metadata guest-state1
# rm /whatever/vm1_temp.qcow2
# virsh dumpxml vm1 > /wherever_backup/vm1.xml



How an automated script could look (specifically).
Written for, and tested on one of my own guests:
--
#!/bin/bash

# Single VM Live Backup automation.
# Requirements: QEMU 2.1+, libvirt-1.2.9+

vmname="win2012R2"
vm_diskloc="/var/lib/libvirt/images"
backupdir="/media/dj/DAS"
logdir="/media/dj/DAS"
tmpdir="/tmp"
snapshot_exceptions="--diskspec hdb,snapshot=no --diskspec hdc,snapshot=no"
target_diskspec="hda"

logtime=`date '+%d-%m-%Y-%H%M'`
exec 1>${logdir}/${vmname}.${logtime}.log 2>&1

echo "Moving machine to temporary disk ..."
virsh domblklist ${vmname}
virsh snapshot-create-as --domain ${vmname} guest-state1 --diskspec \
 ${target_diskspec},file=${tmpdir}/${vmname}_tmp.qcow2 --disk-only --atomic \
 ${snapshot_exceptions}
virsh domblklist ${vmname}

echo "Copying VM ..."
cp ${vm_diskloc}/${vmname}.qcow2 ${backupdir}/${vmname}.${logtime}.qcow2

echo "Commit temporary changes back to main disk and delete temporary snapshot ..."
virsh blockcommit ${vmname} ${target_diskspec} --active --verbose --pivot
virsh domblklist ${vmname}
virsh snapshot-delete ${vmname} --metadata guest-state1
rm ${tmpdir}/${vmname}_tmp.qcow2
virsh dumpxml ${vmname} > ${backupdir}/${vmname}.${logtime}.xml

echo "Cleaning up backups older than 30 days ..."
find ${backupdir}/* -mtime +30 -type f -delete
echo "Done."

# qemu-img convert -p -O qcow2 [filename].vhdx /path/to/images/[filename].qcow2

# qemu-img resize hostname.qcow2 +100GB
  ^ Shut down the VM first, of course. Extend internally afterwards.

Stable Drivers Download
Mount the ISO inside the Windows guest. Using device manager - update drivers by pointing to
the mounted ISO. Make sure to configure the machine to use Virtio first, if it makes sense.

# nano /etc/libvirt/libvirtd.conf
  ^ auth_unix_ro = "none"
    auth_unix_rw = "none"
    auth_tcp = "sasl"

# service libvirtd restart

Download and install VcXsrv on the Windows client:
https://sourceforge.net/projects/vcxsrv/

Start XLaunch and fire up xterm and start GUI apps from there.
If sudo privileges is needed with anything, use with param -E.