wget https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
rpm --import RPM-GPG-KEY-elrepo.org
wget https://www.elrepo.org/elrepo-release-6.el6.elrepo.noarch.rpm
yum install elrepo-release-6.el6.elrepo.noarch.rpm
yum --enablerepo=elrepo-kernel install kernel-lt -y
vi /etc/grub.conf
default=1改为0
重启