Running systemd user units on boot

I have a home server that runs Linux, using cloudflaredd to update my DNS records dynamically. Since my home server does have a few users (@sharaelong uses my home server to host his website), I prefer to run code related to my own domain scoped to my own user.

Since I’d like to update my records even if I’m not logged in, I thought that user systemd unit would be impossible.

Turns out that’s not the case; according to ArchWiki, one can turn on lingering via loginctl enable-linger <username>, and the systemd user instance will start up on boot. Units wanted by the target default.target will be automatically started.

My final ~/.config/systemd/user/cloudflaredd.service file looks like this:

[Unit]
Description=Cloudflare DDNS
After=network.target

[Service]
Type=simple
ExecStart=/home/sungbin/.local/bin/cloudflaredd
Restart=always

[Install]
WantedBy=default.target