Hi @kazoo
Sorry about the delay. I wasn’t clear on the results, and also had to try Installing Duplicati on Ubunutu Linux by @JonMikeIV (although my Linux VM isn’t Linux Lite). The How-To above covers both starting Duplicati at your login (presumably to run as you), and running at boot as a service as root. The service option gets little help from the installer on Windows, and it looks like Linux is the same way. How much do you need this? There’s a benefit from having Duplicati always up, but it does make the picture more complex. Let me explain that some.
How to make Duplicati start automatically with Ubuntu? discusses some of the issues, and shows (but doesn’t discuss) one of the perils. Duplicati can run multiple servers, although you usually wouldn’t need to. The first gets localhost:8200, the next localhost:8300, and so on. The tray Icon hosts a server by default, however the --no-hosted-server option stops it, and is often what you want if you want to use the server that starts at boot.
Duplicati components and Duplicati.GUI.TrayIcon.exe discuss some of this, if you’re not already familiar with it.
If you look inside the /usr/bin/duplicati script, you’ll see it running Tray Icon. It looks like added options simply go at the end, however I’m not sure where you’d put options if you’re using Application Autostart as shown in the link. I haven’t really looked. This reminds me a bit of how to add options to a Windows Tray Icon shortcut.
The results from cat /proc/mount sound weird. There shouldn’t be an error message in the middle of the cat output, although sometimes a process running in the background can intermix output with the foreground process. One guess is that came from your mount.cifs, and the mount -t didn’t show it. Basically, the cat was just to see what the system thought it was supposed to use for its mount, in case you were having problems. Putting the whole thing up probably isn’t necessary, but output talking about smb or cifs might be interesting, although somebody else could possibly get further than I could with explaining exactly how to do your mount.
If the goal is mounts at boot time, it looks like the typical Linux distribution still has one put manual entries in /etc/fstab. I’m not set up to do Linux network mounts, but you probably have man pages for things like fstab and mount. Web sites can offer help. JonMikeIV suggested how to limit the mount to Duplicati’s run. Another (advanced) option might be to automount it only as needed, but I’m not sure there would be any advantage.
I’d note that many people here recommend Duplicati on the source host, rather than the destination as here, however I’m not sure if I’ve found a weighing of all the issues, and perhaps you have reason to prefer yours.
So there’s kind of a shotgun response, partly to save some back-and-forth. I hope this helps with your setup.