Облачное изображение Ubuntu 18.04 не получает DHCP адрес IPv4

Я тестирую облачное изображение LTS Ubuntu 18.04 (20180426.2) на хосте KVM. Существует выполнение сервера DHCP v4, но IPv6 не поддерживается. Когда начальная загрузка облачного изображения, это привычка получает адрес IPv4. Сервису systemd-networkd-wait-online не удалось запуститься:

root@ubuntu:~# systemctl status systemd-networkd-wait-online.service
● systemd-networkd-wait-online.service - Wait for Network to be Configured
   Loaded: loaded (/lib/systemd/system/systemd-networkd-wait-online.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Mon 2018-04-30 11:08:47 UTC; 12min ago
     Docs: man:systemd-networkd-wait-online.service(8)
  Process: 669 ExecStart=/lib/systemd/systemd-networkd-wait-online (code=exited, status=1/FAILURE)
 Main PID: 669 (code=exited, status=1/FAILURE)

Apr 30 11:06:47 ubuntu systemd[1]: Starting Wait for Network to be Configured...
Apr 30 11:08:47 ubuntu systemd-networkd-wait-online[669]: Event loop failed: Connection timed out
Apr 30 11:08:47 ubuntu systemd[1]: systemd-networkd-wait-online.service: Main process exited, code=exited, status=1/FAILURE
Apr 30 11:08:47 ubuntu systemd[1]: systemd-networkd-wait-online.service: Failed with result 'exit-code'.
Apr 30 11:08:47 ubuntu systemd[1]: Failed to start Wait for Network to be Configured.

systemd-сеть не подняла IPv4:

root@ubuntu:~# journalctl -u systemd-networkd
[...]
-- Reboot --
Apr 30 11:06:47 ubuntu systemd[1]: Starting Network Service...
Apr 30 11:06:47 ubuntu systemd-networkd[651]: Enumeration completed
Apr 30 11:06:47 ubuntu systemd[1]: Started Network Service.
Apr 30 11:06:47 ubuntu systemd-networkd[651]: lo: Link is not managed by us
Apr 30 11:06:47 ubuntu systemd-networkd[651]: ens6: IPv6 successfully enabled
Apr 30 11:06:47 ubuntu systemd-networkd[651]: ens6: Gained carrier
Apr 30 11:06:49 ubuntu systemd-networkd[651]: ens6: Gained IPv6LL

root@ubuntu:~# networkctl status ens6
● 2: ens6
       Link File: /run/systemd/network/10-netplan-ens6.link
    Network File: /run/systemd/network/10-netplan-ens6.network
            Type: ether
           State: degraded (configuring)
          Driver: virtio_net
          Vendor: Red Hat, Inc.
           Model: Virtio network device
      HW Address: 02:01:a5:2e:fe:bf
         Address: fe80::1:a5ff:fe2e:febf

Но DHCP v4 настроен:

root@ubuntu:~# cat /etc/netplan/50-cloud-init.yaml 
# This file is generated from information provided by
# the datasource.  Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    version: 2
    ethernets:
        ens6:
            dhcp4: true
            match:
                macaddress: 02:01:a5:2e:fe:bf
            set-name: ens6
root@ubuntu:~# cat /run/systemd/network/10-netplan-ens6.link
[Match]
MACAddress=02:01:a5:2e:fe:bf

[Link]
Name=ens6
WakeOnLan=off
root@ubuntu:~# cat /run/systemd/network/10-netplan-ens6.network 
[Match]
MACAddress=02:01:a5:2e:fe:bf
Name=ens6

[Network]
DHCP=ipv4

[DHCP]
UseMTU=true
RouteMetric=100

Когда я запускаюсь dhclient вручную, сетевое устройство получает адрес IPv4 и достижимо (как ожидалось):

root@ubuntu:~# dhclient
root@ubuntu:~# networkctl status ens6
● 2: ens6
       Link File: /run/systemd/network/10-netplan-ens6.link
    Network File: /run/systemd/network/10-netplan-ens6.network
            Type: ether
           State: routable (configuring)
            Path: pci-0000:00:06.0
          Driver: virtio_net
          Vendor: Red Hat, Inc.
           Model: Virtio network device
      HW Address: 02:01:a5:2e:fe:bf
         Address: 87.106.172.51
                  fe80::1:a5ff:fe2e:febf
         Gateway: 87.106.172.1

Кто-либо знает, почему systemd-networkd не поднимает IPv4 правильно? Это - ошибка, о которой я должен сообщить (против systemd-networkd)?