Import the public key:
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
Install ELRepo for RHEL-7, SL-7or CentOS-7:
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm
Install Latest Kernel
yum --enablerepo=elrepo-kernel install kernel-ml
Check Installed Linux Kernels
rpm -qa |grep kernel
Set Defualt Kernel
grub2-set-default "kernel-ml-4.14.3-1.el7.elrepo.x86_64"
Recreate the Kernel Configuration
grub2-mkconfig -o /boot/grub2/grub.cfg