templates/etc/libvirt/qemu/networks/default.xml.j2

<network>
  <name>default</name>
  <bridge name="virbr0"/>
  <forward/>
  <ip address="{{ mgmt_net_prefix }}.1" netmask="255.255.255.0">
    <dhcp>
      <range start="{{ mgmt_net_prefix }}.2" end="{{ mgmt_net_prefix }}.254"/>
    </dhcp>
  </ip>
</network>