systemd Service & Timer File Generator

systemd starts, supervises and restarts services on almost every modern Linux distribution. A unit file tells it what to run, as which user, with which environment and what to do when the process dies — and a few extra lines sandbox the service so a compromise does less damage. This generator writes the .service file, an optional .timer to run it on a schedule (the systemd replacement for cron), and the commands to install and enable them.

How to use this tool

1. Name the unit and give the full command in ExecStart (absolute path first).
2. Set the working directory, the user and the environment variables.
3. Choose the type and restart policy; keep hardening on and list the paths the service must write to.
4. Optionally pick a schedule, then copy the files to /etc/systemd/system and run the commands shown.

Formula

[Unit] (description, ordering) + [Service] (Type, User, Environment, ExecStart, Restart, hardening) + [Install] (WantedBy)

After= and Wants=network-online.target start the service once the network is up. Restart=on-failure with RestartSec restarts a crashed process after a pause. A timer unit with OnCalendar= starts the service on schedule; such services are Type=oneshot and are enabled through the timer, so they have no [Install] section. Environment values are quoted, and % is written %% because it starts a specifier.

Example

The defaults produce myapp.service: Type=simple, User=myapp, WorkingDirectory=/opt/myapp, Environment="NODE_ENV=production", ExecStart=/usr/bin/node /opt/myapp/server.js, Restart=on-failure, RestartSec=5, the hardening block with ReadWritePaths=/opt/myapp/data, and WantedBy=multi-user.target. Install it with sudo systemctl daemon-reload and sudo systemctl enable --now myapp.service.