PoC: KVM

The Motivation
Running Kernel-based Virtual Machine (KVM) on my local machine instead of

• Microsoft Terminal Server / Remote Desktop
• VMWare
• Proxmox (for now)

Try to use the Linux on board utilities only

Setup

System Information

vmadmin@ts01:~$ sudo -i
root@ts01:~# cat /etc/os-release
PRETTY_NAME="Ubuntu 25.10"
NAME="Ubuntu"
VERSION_ID="25.10"
VERSION="25.10 (Questing Quokka)"
VERSION_CODENAME=questing
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=questing
LOGO=ubuntu-logo

Install and setup packages

root@ts01:~# apt install -y   
qemu-kvm \
libvirt-daemon-system \
libvirt-clients \
bridge-utils \
virt-manager \
cpu-checker

Libvirt (Orchestrator)

• Enable

root@ts01:~# systemctl enable --now libvirtd

• Status

root@ts01:~# systemctl status libvirtd
● libvirtd.service - libvirt legacy monolithic daemon
    Loaded: loaded (/usr/lib/systemd/system/libvirtd.service; enabled; preset: enabled)
    Active: active (running) since Wed 2026-02-04 19:32:47 CET; 52min ago
 Invocation: de3b4269f9074f69aef468813b833a4b
TriggeredBy: ● libvirtd.socket
            ● libvirtd-admin.socket
            ● libvirtd-ro.socket
      Docs: man:libvirtd(8)
            https://libvirt.org/
  Main PID: 26280 (libvirtd)
     Tasks: 25 (limit: 32768)
    Memory: 24.1M (peak: 51M)
       CPU: 9.655s
    CGroup: /system.slice/libvirtd.service
            ├─26280 /usr/sbin/libvirtd --timeout 120
            ├─26388 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
            └─26389 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

Feb 04 20:03:14 ts01 dnsmasq-dhcp[26388]: DHCPDISCOVER(virbr0) 52:54:00:2a:f9:66
Feb 04 20:03:14 ts01 dnsmasq-dhcp[26388]: DHCPOFFER(virbr0) 192.168.122.128 52:54:00:2a:f9:66root@ts01:~# kvm-ok

Virsh (Controler)

• List

root@ts01:~# virsh list --all
virsh list --all
Id   Name       State
--------------------------

• Node Info

root@ts01:~# virsh nodeinfo
CPU model:           x86_64
CPU(s):              24
CPU frequency:       1197 MHz
CPU socket(s):       1
Core(s) per socket:  12
Thread(s) per core:  2
NUMA cell(s):        1
Memory size:         63375964 KiB

• Net List

root@ts01:~# virsh net-list --all
Name      State    Autostart   Persistent

---

default   active   yes         yes

• Set Start

root@ts01:~# virsh net-start default
root@ts01:~# virsh net-autostart default

• Prepare for the first Debian Image

root@ts01:~# cp /home/admin/debian-13.3.0-amd64-netinst.iso /var/lib/libvirt/images
root@ts01:~# chmod 666 /var/lib/libvirt/images/debian-13.3.0-amd64-netinst.iso
root@ts01:~# #Do this only on a sandbox
root@ts01:~# chmod 777 /var/lib/libvirt/images

Prepare KVM User

• User admin:

vmadmin@ts01:~$ usermod -aG libvirt,kvm $USER
vmadmin@ts01:~$ sudo usermod -aG libvirt,kvm $USER
vmadmin@ts01:~$ less /etc/groups

• Optional start user admin in xrdp:

virt-manager

Advanced - Bridging

• advanced, make the vm bridged

root@ts01:~# sudo virsh net-define /dev/stdin <<EOF
<network>
  <name>br0</name>
  <forward mode="bridge"/>
  <bridge name="br0"/>
</network>
EOF

• Start

root@ts01:~# virsh net-start br0
virsh net-autostart br0
Network br0 started

Network br0 marked as autostarted

• Shutdown running VM

root@ts01:~# virsh shutdown debian13
Domain 'debian13' is being shutdown

• Edit

virsh edit debian

• Change:

<interface type='network'>
 <source network='default'/>

• To:

<interface type='bridge'>
 <source bridge='br0'/>
 <model type='virtio'/>
</interface>

Domain 'debian13' XML configuration edited.

Advanced - Converting virtual disks

Converting a VHDX Windows Disk

• Inspect the disk:

root@ts01:~# qemu-img info /home/vmadmin/vm-surf01.vhdx
image: /home/vmadmin/vm-surf01.vhdx
file format: vhdx
virtual size: 127 GiB (136365211648 bytes)
disk size: 41 GiB
cluster_size: 33554432
Child node '/file':
   filename: /home/vmadmin/vm-surf01.vhdx
   protocol type: file
   file length: 41 GiB (43994054656 bytes)
   disk size: 41 GiB

• Get the disk ready for KVM

root@ts01:~# cp /home/admin/debian-13.3.0-amd64-netinst.iso /var/lib/libvirt/images
root@ts01:~# chmod 666 /var/lib/libvirt/images/debian-13.3.0-amd64-netinst.iso
root@ts01:~# chmod 777 /var/lib/libvirt/images

• Convert the disk

root@ts01:~# qemu-img convert -p -f vhdx -O qcow2 \
 /home/vmadmin/vm-surf01.vhdx \
 /var/lib/libvirt/images/vm-surf01.qcow2
   (100.00/100%)

• Inspect the converting results

root@ts01:~# qemu-img info /var/lib/libvirt/images/vm-surf01.qcow2
image: /var/lib/libvirt/images/vm-surf01.qcow2
file format: qcow2
virtual size: 127 GiB (136365211648 bytes)
disk size: 37.6 GiB
cluster_size: 65536
Format specific information:
   compat: 1.1
   compression type: zlib
   lazy refcounts: false
   refcount bits: 16
   corrupt: false
   extended l2: false
Child node '/file':
   filename: /var/lib/libvirt/images/vm-surf01.qcow2
   protocol type: file
   file length: 37.6 GiB (40399208448 bytes)
   disk size: 37.6 GiB

Converting a VMDK VMWare Disk

• Inspect

root@ts01:~# qemu-img info /var/lib/libvirt/ qemu-img info 'Windows 8.x x64.vmdk' 
image: Windows 8.x x64.vmdk
file format: vmdk
virtual size: 100 GiB (107374182400 bytes)
disk size: 16.7 GiB
cluster_size: 65536
Format specific information:
   cid: 2432867383
   parent cid: 4294967295
   create type: monolithicSparse
   extents:
       [0]:
           virtual size: 107374182400
           filename: Windows 8.x x64.vmdk
           cluster size: 65536
           format:
Child node '/file':
   filename: Windows 8.x x64.vmdk
   protocol type: file
   file length: 16.7 GiB (17974165504 bytes)
   disk size: 16.7 GiB

• Convert

root@ts01:~# qemu-img convert -f vmdk -O qcow2 'Windows 8.x x64.vmdk' win8.qcow2

VM Installation

Installation Debian from ISO

• VM Installer01

• VM Installer02

• VM Installer05

• VM Installer06

• VM Installer07

• VM Installer08

• VM Installer09

• VM Installer10

• VM Installer11

• VM Installer12

Installation Win10 VM (former vhdx file)

• Install01

• Install02

• Install03

• Install04

• Win10 in running state

USB Operations

Attach a USB Stick to the VM

• Get attached devices
  • Note: We're after ID 0781:5591 SanDisk Corp.

root@ts01:~# lsusb
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 001 Device 002: ID 8087:800a Intel Corp. Hub
 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 002 Device 002: ID 3938:1032 MOSART Semi. 2.4G RF Keyboard & Mouse
 Bus 002 Device 003: ID 04b3:3025 IBM Corp. NetVista Full Width Keyboard
 Bus 002 Device 004: ID 17aa:1034 VIA Labs, Inc.          USB Hub
 Bus 002 Device 005: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller
 Bus 002 Device 006: ID 046d:c52b Logitech, Inc. Unifying Receiver
 Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 003 Device 002: ID 17aa:1034 VIA Labs, Inc.          USB Hub
 Bus 003 Device 003: ID 0781:5591 SanDisk Corp. Ultra Flair
 Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 004 Device 002: ID 8087:8002 Intel Corp. 8 channel internal hub

• Attach SanDisk to win10

root@ts01:~# virsh attach-device win10 --file <(cat <<EOF
<hostdev mode='subsystem' type='usb'>
  <source>
    <vendor id='0x0781'/>
    <product id='0x5591'/>
  </source>
</hostdev>
EOF
) --persistent
Device attached successfully

• Optional dump message to investigate the current settings

root@ts01:~# virsh dumpxml win10 | grep -A10 hostdev
   <hostdev mode='subsystem' type='usb' managed='no'>
     <source>
       <vendor id='0x0781'/>
       <product id='0x5591'/>
     </source>
     <address type='usb' bus='0' port='4'/>
     ....

• Shutdown Win10

root@ts01:~# virsh shutdown win10
Domain 'win10' is being shutdown

• Start back win10

root@ts01:~# virsh start win10
Domain 'win10' started

• Get Status

root@ts01:~# virsh list --all
 Id   Name       State
---------------------------
 3    win10      running
 -    debian13   shut off

• Attached USB Stick to Win10

Detach a USB Stick from the VM

• Detach device

root@ts01:~# virsh detach-device win10 --file <(cat <<EOF
<hostdev mode='subsystem' type='usb'>
  <source>
    <vendor id='0x0781'/>
    <product id='0x5591'/>
  </source>
</hostdev>
EOF
) --persistent
Device detached successfully

Basic admin commands

Cloning a machine

Cloning win10 to win10a

• Shutdown Main

root@ts01:~# virsh shutdown win10
Domain 'win10' is being shutdown

root@ts01:~# virsh list --all
 Id   Name       State
---------------------------
 3    win10      running
 -    debian13   shut off

• Clone

• Clone Process

root@ts01:~# virt-clone \
  --original win10 \
  --name win10a \
  --auto-clone
Allocating 'vm-surf01-clone.qcow2'                                              | 127 GB  00:02:21

Clone 'win10a' created successfully.

Snapshots

• Create a snapshort

root@ts01:~# virsh snapshot-create win10a
Domain snapshot 1770483334 created
root@ts01:~# virsh snapshot-list win10a
 Name         Creation Time               State
---------------------------------------------------
 1770483334   2026-02-07 17:55:34 +0100   running

• Revert snapshort

root@ts01:~# virsh snapshot-revert win10a 1770483334
Domain snapshot 1770483334 reverted

Hibernate

• Hibernate with managedsave

root@ts01:~# virsh managedsave win10a

Domain 'win10a' state saved by libvirt

• List

root@ts01:~# virsh list --all
 Id   Name       State
---------------------------
 3    win10      running
 4    debian13   running
 -    win10a     shut off

• Start back

root@ts01:~# virsh start win10a
Domain 'win10a' started

Backup/Restore of the VM settings

To Backup the VM settings only run:

virsh list --all
virsh dumpxml vmname > vmname.xml

• To Restore

virsh define vmname.xml

Adding a new VM Storage

Partition the new storage

root@ts01:~# parted /dev/nvme0n1
GNU Parted 3.6
Using /dev/nvme0n1
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) mklabel gpt
Warning: The existing disk label on /dev/nvme0n1 will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes/No? y
(parted) quit
Information: You may need to update /etc/fstab.

Add Filesystem

root@ts01:~# mkfs.ext4 /dev/nvme0n1p1
mke2fs 1.47.2 (1-Jan-2025)
/dev/nvme0n1p1 contains a ntfs file system labelled 'NVM'
Proceed anyway? (y,N) y
Discarding device blocks: done
Creating filesystem with 500099328 4k blocks and 125026304 inodes
Filesystem UUID: 2382c329-2c7c-4a57-855d-aea09003dd30
Superblock backups stored on blocks:
       32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
       4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
       102400000, 214990848

Allocating group tables: done
Writing inode tables: done
Creating journal (262144 blocks): done
Writing superblocks and filesystem accounting information: done

Mount Filesystem

• Make and mount

root@ts01:~# mkdir /vmstorage
root@ts01:~# mount /dev/nvme0n1p1 /vmstorage

• Check

root@ts01:~# df -h
Filesystem      Size  Used Avail Use% Mounted on
tmpfs           6.1G   16M  6.1G   1% /run
/dev/sda2       915G  459G  411G  53% /
tmpfs            31G     0   31G   0% /dev/shm
efivarfs        256K  148K  104K  59% /sys/firmware/efi/efivars
tmpfs           5.0M   12K  5.0M   1% /run/lock
tmpfs           1.0M     0  1.0M   0% /run/credentials/systemd-journald.service
tmpfs           1.0M     0  1.0M   0% /run/credentials/systemd-resolved.service
/dev/sda1       1.1G  6.3M  1.1G   1% /boot/efi
tmpfs            31G  8.0K   31G   1% /tmp
tmpfs           6.1G  116K  6.1G   1% /run/user/60578
tmpfs           6.1G  108K  6.1G   1% /run/user/1000
/dev/nvme0n1p1  1.9T  2.1M  1.8T   1% /vmstorage

• Get UUID

root@ts01:~# blkid /dev/nvme0n1p1
/dev/nvme0n1p1: UUID="2382c329-2c7c-4a57-855d-aea09003dd30" BLOCK_SIZE="4096" TYPE="ext4" PARTLABEL="primary" PARTUUID="f49249d9-50eb-45bd-aafc-701ef7d66f5b"

• Add to /etc/fstab

UUID=2382c329-2c7c-4a57-855d-aea09003dd30  /vmstorage  ext4  defaults  0 2

• Reboot to test!

Create a new Pool and apply new VMs

• List current pool

root@ts01:~# virsh pool-list --all
 Name        State    Autostart
---------------------------------
 default     active   yes

• Create a new pool using the new vmstorage

root@ts01:~# virsh pool-define-as nvme-pool dir --target /vmstorage
Pool nvme-pool defined
root@ts01:~# virsh pool-build nvme-pool
Pool nvme-pool built
root@ts01:~# virsh pool-start nvme-pool
Pool nvme-pool started
root@ts01:~# virsh pool-autostart nvme-pool
Pool nvme-pool marked as autostarted

• List current pool

root@ts01:~# virsh pool-list --all
 Name        State    Autostart
---------------------------------
 default     active   yes
 nvme-pool   active   yes

• Move the VM to another disk

root@ts01:~# mv /var/lib/libvirt/images/vm-win10a.qcow2 /vmstorage/vm-win10.qcow2

• Edit the vm settings

root@ts01:~# virsh edit win10a

• Then:
  • set source file to:
  • /vmstorage/vm-win10.qcow2

• And save

Domain 'win10a' XML configuration edited.