we will use ELRepo to install kernel
1. rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
2. rpm -Uvh http://www.elrepo.org/elrepo-release-6-6.el6.elrepo.noarch.rpm
[elrepo-kernel]
enabled=１
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
protect=0
3. yum --enablerepo=elrepo-kernel -y install kernel-lt
4. vi /etc/grub.conf
5. reboot