kvm bridge network with systemd-networkd 802.3ad bonding

[Gary Dale <garyndp@gmail.com>]

I've added a second NIC to a server and am trying to configure the 
virtual bridge network to work with it.

I configured the network bonding initially as per 
https://wiki.debian.org/Bonding#Using_systemd-networkd but I couldn't 
get virt-manager to take bond0 as the bridge device (using the Virtual 
Machine Manager gui). I eventually go it to accept it by removing the 
[Network] Address, etc. from my /etc/networkd-systemd/management.network 
file (which I normally use to specify the bond0 address, etc.) and then 
reworked my old /etc/network/interfaces file to refer to bond0 instead 
of eth0.

This seems to bring up bond0 with br0 having the correct static IP, 
etc.. However it seems somewhat archaic. I think it should be possible 
to use only systemd-networkd to make this work. Also, I may have some 
issues with connectivity - initial connections to the virtual machine 
sometimes fail.

Any suggestions?