Xvfb, or X virtual frame buffer is needed by selenium and chromedriver or gekodriver, so it can run via cron with your PC locked, or without your script taking focus from the user section.

Installing

yum install xorg-x11-server-Xvfb

Copy below to /etc/systemd/system/Xvfb.service

[Unit]
Description=X Virtual Frame Buffer Service
After=network.target

[Service]
ExecStart=/usr/bin/Xvfb :99 -screen 0 1024x768x24

[Install]
WantedBy=multi-user.target

chmod +x /etc/systemd/system/Xvfb.service
systemctl enable Xvfb.service
systemctl start Xvfb.service