Red Hat Certified Architect (RHCA) Certification Practice Exam

The command used to reboot a RHEL 8 server is "systemctl reboot." This command leverages the systemd system and service manager, which is the default initialization system in RHEL 8 and other modern Linux distributions.

When you issue the "systemctl reboot" command, it tells the system to perform a controlled reboot, allowing all currently running services to gracefully stop before the system restarts. This is vital for ensuring that the system maintains its integrity and that processes have the opportunity to save any necessary data or perform clean-up tasks prior to shutting down.

The other options are not suitable for rebooting in this context. For example, using "service reboot" is not a recognized command for managing the system's state in RHEL 8, as the traditional SysV init system has been largely replaced by systemd. The "shutdown -r now" command is valid and does also initiate a reboot, but it is being superseded by the more versatile "systemctl" commands in newer Linux versions. The command "reboot system" is also incorrect because the syntax does not align with the expected command structure in the system.

Thus, "systemctl reboot" is the preferred and recommended command for rebooting a RHEL