Boot Grub2 Kernel Labs

Remove “quiet” from the end of the value of the variable GRUB_CMDLINE_LINUX in the /etc/default/grub file
Run grub2-mkconfig to apply the update.
Reboot the system and observe that the system now displays verbose information during the boot process.

Reset the root user password by booting the system into emergency mode with SELinux disabled.
Try to log in with root and enter the new password after the reboot.

Check the current version of the kernel using the uname or rpm command.
Download a higher version from the Red Hat Customer Portal or rpmfind.net and install it.
Reboot the system and ensure the new kernel is listed on the bootloader menu.

download the latest available kernel packages from the Red Hat Customer Portal \
install them using the dnf command.
ensure that the existing kernel and its configuration remain intact.

As an alternative (preferred) to downloading kernel packages individually and then installing them, you can follow the instructions provided in “Containers” chapter to register server1 with RHSM and run sudo dnf install kernel to install the latest kernel and all the dependencies collectively.

Check the version of the running kernel: uname -r
List the kernel packages currently installed: rpm -qa | grep kernel
Sign in to the Red Hat Customer Portaland click downloads.
Click “Red Hat Enterprise Linux 8” under “By Category”:
Click Packages and enter “kernel” in the Search bar to narrow the list of available packages:
Click “Download Latest” against the packages kernel, kernel-core, kernel-headers, kernel-modules, kernel-tools, and kernel-tools-libs to download them.
Once downloaded, move the packages to the /tmp directory using the mv command.
List the packages after moving them:
Install all the six packages at once using the dnf command: dnf install /tmp/kernel* -y
Confirm the installation alongside the previous version: sudo dnf list installed kenel*
The /boot/grub2/grubenv/ file now has the directive “saved_entry” set to the new kernel, which implies that this new kernel will boot up on the next system restart: sudo cat /boot/grub2/grubenv
Reboot the system. You will see the new kernel entry in the GRUB2 boot list at the top. The system will autoboot this new default kernel.
Run the uname command once the system has been booted up to confirm the loading of the new kernel: uname -r
View the contents of the version and cmdline files under /proc to verify the active kernel: `cat /proc/version

Or just dnf install kernel