Choose an image: https://cloud-images.ubuntu.com/daily/server/groovy/current/
See also https://serverascode.com/2018/06/26/using-cloud-images.html
cd /tmp
wget -c https://cloud-images.ubuntu.com/daily/server/groovy/current/groovy-server-cloudimg-amd64-disk-kvm.img
qemu-img resize groovy-server-cloudimg-amd64-disk-kvm.img 20G
virt-customize -a groovy-server-cloudimg-amd64-disk-kvm.img --root-password password:ubuntu
virt-customize -a groovy-server-cloudimg-amd64-disk-kvm.img --uninstall cloud-init
virsh define vm.xml
virsh start vm1
virsh console vm1User is root and password is ubuntu.
Inside machine,
growpart /dev/vda 1
resize2fs /dev/vda1
dhclient
ip ad
apt update
apt install network-manager
touch /etc/NetworkManager/conf.d/10-globally-managed-devices.conf
systemctl restart NetworkManager