What `ulimit` value applies to a `systemd` service?

I have a systemd service installed. It was creating some problems and I am speculating that it might be file descriptor stuff. The file descriptor limit systemd wide is quite high: $ cat /proc/sys/fs/file-max 378259 But the soft limit seems to be the default: $ ulimit -Hn 1048576 $ ulimit -Sn 1024 Which of these limits applies to my systemd service? It is started as a dedicated user: [Unit] Description=Myservice After=network.target StartLimitIntervalSec=0 [Service] Type=simple WorkingDirectory=/home/app Restart=always RestartSec=1 User=app ExecStart= And user app is a regular user (/etc/passwd): app:x:1002:1002:APP user:/home/app:/bin/sh In other words, what exact number triggers a limit for the systemd service I am running, what exact number will result in a failure when an additional fd is opened?