KVM
KVM on Debian 12, tested on the N100 Mini PC.
Install
Some of these tools will require an X11 server which can be VxSrv on Windows, for example.
apt install --no-install-recommends qemu-system libvirt-clients libvirt-daemon-system virt-viewer virtinst virt-manager qemu-utils
qemu
To allow a user to create a virtual network permissions must be altered for a qemu script.
If it doesn't exist, create a script `/etc/rc.local'.
#! /bin/bash chmod u+s /usr/lib/qemu/qemu-bridge-helper exit 0
Make the script executable and run it.
chmod +x /etc/rc.local && /etc/rc.local
To make this script run at every boot with systemd add the following to `/etc/systemd/system/rc-local.service'
[Service] Type=oneshot RemainAfterExit=yes ExecStart=/etc/rc.local [Install] WantedBy=multi-user.target
Enable the service with
systemctl enable rc-local.service
User
Add login to group(s).
Debian says add your login to group libvirt and other guides recommend group kvm as well. The latter group requirement is unknown.
adduser `login' libvirt adduser `login' kvm
Test
Export the hostname of your X11 server and on that host allow access via xhost.
setenv DISPLAY excellent:0.0 virt-manager
Directories
VM storage
mkdir -p /opt/VM chown 0:0 /opt/VM chmod 1777 /opt/VM
ISO storage
mkdir -p /opt/ISO cd /opt/ISO wget https://cdimage.debian.org/debian-cd/current/amd64/iso-dvd/debian-12.4.0-amd64-DVD-1.iso sha256sum debian-12.4.0-amd64-DVD-1.iso 3a85e04f0bbdf7ba0cdd7537dd781c583f70754db67e5a757f113442cade56ea debian-12.4.0-amd64-DVD-1.iso
VM
Create
Interactive
This example uses a fixed MAC address.
#! /bin/sh
export PATH=/bin:/sbin
NAME="debian12"
DVD="/opt/ISO/debian-12.4.0-amd64-DVD-1.iso"
DISK="/opt/VM/${NAME}.qcow2,size=20,format=qcow2"
virsh destroy ${NAME}
virsh undefine ${NAME}
rm -f ${DISK}
virt-install \
--name "${NAME}" \
--ram 1024 \
--disk path="${DISK}" \
--vcpus 1 \
--os-variant debian11 \
--network bridge=br0,mac=02:00:c0:a8:00:6e \
--graphics none \
--console pty,target_type=serial \
--location "${DVD}" \
--extra-args 'console=ttyS0'
Non interactive
Append the following to the interactive script above
--initrd-inject preseed.cfg --noautoconsole --wait
This preseed file uses a fixed IP address.
List
virsh list --all
Start
virsh start debian12
Auto start
virsh autostart debian12
No auto start
virsh autostart --disable debian12
Information
virsh dominfo debian12
Console
virsh console debian12
Stop
virsh shutdown debian12
NB there are optional modes
Force stop
virsh destroy debian12
Delete
virsh undefine debian12
Export
virsh dumpxml debian12 > debian12.xml
Import
virsh define debian12.xml
Disk
Tools
apt install guestfs-tools
Info
qemu-img info vm1.qcow2
image: vm1.qcow2
file format: qcow2
virtual size: 20 GiB (21474836480 bytes)
disk size: 3.42 GiB
cluster_size: 65536
Format specific information:
compat: 1.1
compression type: zlib
lazy refcounts: true
refcount bits: 16
corrupt: false
extended l2: false
Compact
virt-sparsify --in-place vm1.qcow2 100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ --:-- [ 6.4] Trimming /dev/sda1 [ 6.8] Clearing Linux swap on /dev/sda5 [ 7.1] Sparsify in-place operation completed with no errors
Resize
qemu-img resize vm1.qcow2 40G
qemu-img info vm1.qcow2
image: vm1.qcow2
file format: qcow2
virtual size: 40 GiB (42949672960 bytes)
disk size: 2.49 GiB
cluster_size: 65536
Format specific information:
compat: 1.1
compression type: zlib
lazy refcounts: true
refcount bits: 16
corrupt: false
extended l2: false
VM
sudo apt-get install gparted
Run gparted to re-arrange and resize the partitions as appropriate
