Create a systemd service for a script or app (.service file)

To run a script or application as a systemd service, create a unit file such as /etc/systemd/system/myapp.service with a [Service] section whose ExecStart= is the absolute path of the command, run sudo systemctl daemon-reload, then sudo systemctl enable --now myapp. systemd then starts it at boot, restarts it if you set Restart=, and collects its output in the journal (journalctl -u myapp). The program must stay in the foreground; systemd does the backgrounding.

A minimal service

[Unit]
Description=My app API server
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
User=myapp
WorkingDirectory=/opt/myapp
Environment=PORT=8080
ExecStart=/opt/myapp/venv/bin/python /opt/myapp/server.py
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl enable --now myapp
systemctl status myapp
journalctl -u myapp -f

/opt/myapp, the myapp user and the Python command stand for your own application. Create the user first (sudo useradd --system --home /opt/myapp myapp) or remove the User= line to run as root, which is rarely a good idea.

Main settings

Pitfalls

• Relative paths and PATH. systemd does not read your shell profile. Use absolute paths in ExecStart= and set variables with Environment=.
• Forgetting daemon-reload. After creating or editing a unit, systemd still uses the old copy and prints Warning: The unit file, source configuration file or drop-ins of myapp.service changed on disk. Run 'systemctl daemon-reload' to reload units.
• Script without a shebang or execute bit. ExecStart=/opt/myapp/run.sh fails with Exec format error or Permission denied (status 203/EXEC). Add #!/bin/bash and chmod +x.
• Restart loops. With Restart=always and a program that exits at once, systemd stops after five starts within ten seconds with Start request repeated too quickly.
• Editing packaged units. Use sudo systemctl edit nginx to create a drop-in override instead of changing files under /usr/lib/systemd/system/.

Check the unit file

systemd-analyze verify /etc/systemd/system/myapp.service reports unknown settings and missing executables before you start it. After starting, systemctl status myapp shows active (running), the main PID and the last log lines; if the start fails, journalctl -u myapp -n 50 shows the program's own error.

FAQ