How to Install or Upgrade to Kernel 4.20 in RHEL 7

# uname -sr

# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
# rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm

#yum --disablerepo="*" --enablerepo="elrepo-kernel" list available

# yum --enablerepo=elrepo-kernel install kernel-ml

#reboot

Select new kernel 

Set Default Kernel Version in GRUB


# vi /etc/default/grub

GRUB_TIMEOUT=5
GRUB_DEFAULT=0
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rd.lvm.lv=centos/root rd.lvm.lv=centos/swap crashkernel=auto rhgb quiet"
GRUB_DISABLE_RECOVERY="true"


Next, run the following command to recreate the kernel configuration.

Rebuild the /boot/grub2/grub.cfg file by running the grub2-mkconfig -o command as follows:

On BIOS-based machines: ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
On UEFI-based machines: ~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg