For my project, I am using a balenFIN v1.1.0 devkit with the latest balenOS updates. Connected to the miniPCIE port, a Quectel UC20 3G chip and a Twilio SIM Card.
The goal is to make the balenaFIN a cellular gateway to a local wired network. So, on the one side, a cellular connection with internet access, on the other side, a wired connection on a local network without internet access.
Using the configuration in https://www.balena.io/docs/reference/OS/network/2.x/, and setting the eth0 interface with a static IP and ipv4 never default, I would expect the cellular connection to stay online all the time.
However, after staying online for a couple of days sometime, the connection is lost (status in balenaCloud is offline, and I cannot open a terminal session). Rebooting the device sometimes brings it back up, sometimes does not.
I’ve seen a topic where it was said that a container shutting down could also bring down the interface due to interference with udev.
I maybe suspect the wired connection to get a higher routing priority due to the cellular connection failing sometimes, but that should not happen with the never_default option, right?
Did you encouter a similar issue in your projects? My dream would be to have a NetworkManager configuration for a non-stop cellular connection for remote access + a LAN connection via eth0.