How to debug systemd-networkd?

Solution 1:

From https://coreos.com/os/docs/latest/network-config-with-networkd.html :

mkdir -p /etc/systemd/system/systemd-networkd.service.d/

Create Drop-In /etc/systemd/system/systemd-networkd.service.d/10-debug.conf with following content:

[Service]
Environment=SYSTEMD_LOG_LEVEL=debug

And restart systemd-networkd service:

systemctl daemon-reload
systemctl restart systemd-networkd
journalctl -b -u systemd-networkd