virt-install -n web_devel -r 2048 --disk path=/var/lib/libvirt/images/web_devel.img,bus=virtio,size=16 -c /var/lib/libvirt/images/ubuntu-18.04.1-live-server-amd64.iso --network network=default,model=virtio --graphics vnc,listen=0.0.0.0 --noautoconsole -v

<disk type='file' device='disk'>
  <driver name='qemu' type='qcow2'/>
  <source file='/var/lib/libvirt/images/web_devel.img'/>
  <target dev='vda' bus='virtio'/>
  <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
</disk>

<disk type='block' device='disk'>
  <driver name='qemu' type='raw' cache='none' io='native'/>
  <source dev='/dev/cloud/test_web_devel'/>
  <target dev='vda' bus='virtio'/>
  <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
</disk>