I have a weird behavior that I cannot understand. I am running on a Raspberry Pi OS (Debian Trixie).
If I create a simple file /lib/systemd/system/foo.service without enabling it.
[Unit]
Description=Foo
[Service]
Type=oneshot
ExecStart=/bin/echo FOO
[Install]
WantedBy=multi-user.target
It somehow gets started after I reboot even though I did not enable it and ends up as a symlink in /etc/systemd/system/multi-user.target.wants/foo.service.
If I disable it the symlink disappears but reappears after a reboot.
I checked the presets in /lib/systemd/system-preset/*.preset but there is no wildcard.
What else could I check and is this an expected behavior? I have an Arch Linux machine as well as an Ubuntu one on my PC and I do not see this behavior.
