Automate Linux Service Startup: Crontab @reboot vs Systemd Service

1. Introduction

After a power outage, many services need to be restarted manually; creating a startup script and adding it to /etc/rc.local is a common but inelegant solution.

$ cat /etc/rc.local
bash /root/script/restart.sh

This works but lacks sophistication. Below are two better approaches.

2. Using Crontab

Crontab supports the @reboot directive to run commands after the system boots. First, edit the crontab:

$ crontab -e

Then add the following line:

@reboot /root/script/restart.sh

After saving, the script will automatically execute on reboot. Additional advanced usage includes delayed execution:

# Run the script 5 minutes after boot
@reboot sleep 300 && /home/wwwjobs/clean-static-cache.sh

3. Using Systemd

Create a Systemd service file named restart.service:

$ vim /lib/systemd/system/restart.service

[Unit]
Description=restart
After=default.target

[Service]
ExecStart=/root/script/restart.sh

[Install]
WantedBy=default.target

Enable the service:

$ systemctl daemon-reload
$ systemctl enable restart.service

Now the associated script will start automatically on boot.

4. References

https://www.google.com

https://tinyurl.com/6ryafefw

https://www.cyberciti.biz/faq/linux-execute-cron-job-after-system-reboot/