[/etc/systemd/network/10-bond0.network]

[Match]
Name=bond0

[Network]
Address=192.168.0.40/24

---
[/etc/systemd/network/20-eth0.network]

[Match]
Name=eth0
KernelCommandLine=!root=/dev/nfs

[Network]
Bond=bond0

---
[/etc/systemd/network/21-eth1.network]

[Match]
Name=eth1
KernelCommandLine=!root=/dev/nfs

[Network]
Bond=bond0

---
[/etc/systemd/network/30-bond0.netdev]

[NetDev]
Name=bond0
Kind=bond

[Bond]
Mode=active-backup
MIIMonitorSec=100ms