刚刚安装了ubuntu服务器18.04。我无法使用 systemd-networkd 获得 dhcp 租约，但使用 dhclient 工作正常。
使用 SYSTEMD_LOG_LEVEL=debug 我得到：
$ journalctl
...
Apr 29 10:14:09 computer systemd-networkd[2169]: enp3s0: Link state is up-to-date
Apr 29 10:14:09 computer systemd-networkd[2169]: enp3s0: found matching network '/etc/systemd/network/10-netplan-enp3s0.network'
Apr 29 10:14:09 computer systemd-networkd[2169]: wlp2s0: Link is not managed by us
Apr 29 10:14:09 computer systemd-networkd[2169]: lo: Link is not managed by us
Apr 29 10:14:09 computer systemd-networkd[2169]: LLDP: Started LLDP client
Apr 29 10:14:09 computer systemd-networkd[2169]: enp3s0: Started LLDP.
Apr 29 10:14:09 computer systemd-networkd[2169]: enp3s0: …