[root@grover network]# ls
br0.netdev  br0.network  eth0.network
[root@grover network]# cat br0.netdev
[NetDev]
Name=br0
Kind=bridge
[root@grover network]# cat br0.network
[Match]
Name=br0

[Network]
Address=192.168.7.2/24
Gateway=192.168.7.1
DNS=192.168.7.1
Address=2001:4830:1100:xxxx::2/64
Gateway=2001:4830:1100:yyyy::1
DNS=2001:4860:4860::8888
DNS=2001:4860:4860::8844
[root@grover network]# cat eth0.network
[Match]
Name=eth0

[Network]
Bridge=br0

root@grover network]# ps -ef | grep kvm
root       279     2  0 17:42 ?        00:00:00 [kvm-irqfd-clean]
ed        4535     1  0 19:50 ?        00:00:13 qemu-system-x86_64 -name host -nographic -m 4G -smp 6 -enable-kvm -cpu host -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic0 -drive file=/home/jail/host.img,if=virtio -serial pty -monitor telnet:localhost:7100,server,nowait,nodelay

[root@host network]# ls
br1.netdev  br1.network  eth0.network 
[root@host network]# cat br1.netdev
[NetDev]
Name=br1
Kind=bridge
[root@host network]# cat br1.network
[Match]
Name=br1

[Network]
Address=192.168.7.9/24
Gateway=192.168.7.1
DNS=192.168.7.1
Address=2001:4830:1100:xxxx::9/64
Gateway=2001:4830:1100:xxxx::2
DNS=2001:4860:4860::8888
DNS=2001:4860:4860::8844
[root@host network]# cat eth0.network
[Match]
Name=eth0

[Network]
Bridge=br1
[root@host network]# ps -ef | grep nspawn
root       400     1  0 20:03 ?        00:00:00 /usr/bin/systemd-nspawn --quiet --keep-unit --boot --link-journal=guest --network-bridge=br1 --directory=/...

root@dev network]# ls
host0.network
[root@dev network]# cat host0.network
[Match]
Name=host0

[Network]
Address=2001:4830:1100:xxxx::a/64                                                                                                                     
Gateway=2001:4830:1100:xxxx::2