How create a service or run a script at boot time in RHEL7

How create a service or run a script at boot time in RHEL7?

1. [root@example.com system]# vi /etc/systemd/system/loopfscobbler.service
2. Put this content in the file.

[Unit]
Description=Loop FS mount for  Cobbler
After=network.target

[Service]
Type=simple
ExecStart=/usr/local/sbin/loopfscobbler.sh
TimeoutStartSec=0

[Install]
WantedBy=default.target


3. create a script.
[root@example.com system]# vi /usr/local/sbin/loopfscobbler.sh
4. Make the script executable.
[root@example.com system]# chmod +x /usr/local/sbin/loopfscobbler.sh
5. Enable the service to start across boot.
systemctl enable loopfscobbler.service
6. Reboot the system to check.