我在 ubuntu 18.04 上使用 netplan 设置了桥接器，一切看起来正常：
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet myip netmask 255.255.255.192 broadcast someip
inet6 myip prefixlen 64 scopeid 0x20<link>
ether hidden txqueuelen 1000 (Ethernet)
RX packets 27382 bytes 5374960 (5.3 MB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8381 bytes 2177553 (2.1 MB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet myip netmask 255.255.255.192 broadcast someip
ether 28:92:4a:36:8f:0e txqueuelen 1000 (Ethernet)
RX packets 31969 bytes 8078978 (8.0 MB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8955 bytes 2267155 (2.2 MB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 16 memory 0xfbee0000-fbf00000
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 15298 bytes 4480739 (4.4 MB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 15298 bytes 4480739 (4.4 MB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
如您所见，br0 桥接网络正常。
我可以启动 virtnetwork.service，但是它上没有 Bridges 网络：
virtnetwork[11291]: Error: No ip address found.
我的从属设置看起来很好，上面有 br0 名称，我也尝试使用 enp2s0。
任何帮助都将不胜感激。