GRUB - Grand Unified Boot Loader

Ramdisk / Kernel

initramfs - drivers to access the root file system at boot time

kernel - core operating system

/boot/loader/entries

Kernels, ramfs, and rescue systems are stored in the /boot directory,

Check kernel version

uname -r

After installing a new kernel version, a server reboot is required.

Grub options are configured within /boot/grub2/grubenv

resume (rarely used) - essentially for systems with a 'sleep mode' - not really ever used on servers, more of a desktop feature.

rhgb (rarely used) - graphical boot screen, rather than text - not really ever used on a server, more of a desktop feature.

quiet (rarely used) - hides the boot output when booting a system up - not really ever used on a server, more of a desktop feature.

Grub options can be changed using the grubby command

remove rhgb feature for all kernels installed

grubby --update=ALL --remove-args="rhgb"

Changes made using grubby modify the grubenv file, which in turn alters the kernel files stored in /boot/loader/entries