I added a route to the configuration of some EC2 instance like:
networking.interfaces.eth0.ipv4.routes = [ ... ];
After deploying this I noticed the route wasn’t configured and the following appeared in my journal:
systemd: sys-subsystem-net-devices-eth0.device: Job sys-subsystem-net-devices-eth0.device/start timed out. systemd: Timed out waiting for device sys-subsystem-net-devices-eth0.device. systemd: Dependency failed for Address configuration of eth0. systemd: network-addresses-eth0.service: Job network-addresses-eth0.service/start failed with result 'dependency'.
sys-subsystem-net-devices-eth0.device timing out?
I do see the following in my journal soon after booting which might have something to do with it:
systemd-udevd: Error changing net interface name 'eth0' to 'ens5': Device or resource busy systemd-udevd: could not rename interface '2' from 'eth0' to 'ens5': Device or resource busy
Note that this is a fairly minimal NixOS 19.03 configuration running on EC2.