查看当前

uname -r 

1.导入key

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

2.安装elrepo的yum源

rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm

3.安装内核

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

4.查看默认启动顺序

awk -F\‘ ‘$1=="menuentry " {print $2}‘ /etc/grub2.cfg

grub2-set-default 0

删除旧内核

yum remove kernel

centos7 升级内核