[CentOS] Allowing non-root users to reboot a workstation

Did you try adding

UserName ALL= NOPASSWD: /sbin/reboot

As the last line of their /etc/sudoers files?
(replacing UserName with their actual user name, of course.)

That should grant them root access to only the /sbin/reboot command (add
more commands using comma delimiting).

Then they just run
$ sudo reboot


If you want to require they enter their own password before rebooting, use
the line

UserName ALL=/sbin/reboot

Instead.

Use of sudo is recorded in /var/log/secure, if I recall correctly.