Q: You need to run a long-lived background service that must automatically restart if it crashes. You also want to manage its lifecycle (start/stop/restart) from a single systemd unit file. How do you configure systemd for auto-restart, and what are the critical directives?

Modern Linux systems use systemd to manage services instead of SysVinit scripts. A systemd unit file (e.g., /etc/systemd/system/myapp.service) must configure restart behavior explicitly.

• Type=simple (default): The process runs in the foreground. Systemd considers the service active when the process starts.
• Type=forking: The process daemonizes itself (old SysVinit behavior). Systemd waits for the parent to exit before considering it active.
• Restart=on-failure: Automatically restart if the process exits with a non-zero exit code.

Key directives: Example configuration: Then enable and start: systemctl daemon-reload && systemctl enable myapp && systemctl start myapp.

[Unit]
Description=My Critical Application
After=network.target

[Service]
Type=simple
ExecStart=/usr/local/bin/myapp
Restart=on-failure
RestartSec=5
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

• RestartSec=5: Wait 5 seconds between restart attempts to avoid restart loops.
• StandardOutput=journal and StandardError=journal: Capture all logs directly to journald (no separate log files needed).