No netctl here :)
I systemd-networkd enabled on boot and 3 files in /etc/systemd/network
cat brkvm.netdev [NetDev] Name=brkvm Kind=bridge
cat brkvm.network [Match] Name=brkvm
[Network] Description=Bride for use with virtual machines and containers Address=192.168.56.1/24
cat vb-veth.network [Match] Name=vb-*
This last one is sort of a hack to bring the network up as it shows up, I suppose systemd-nspawn should do it by itself, this might be a bug, unless there is a good reason not to bring the network up automatically.
Inside the container I do manual setup of the network address since I'm not actually booting it.
Mind you that you may have to do systemctl daemon-reload (not really sure if this one is needed) and restart systemd-networkd for any changes to make effect.
-- Mauro Santos
Thank you Muaro. Will try to get rid of the bridge netctl profile then.