一、升级内核
1、更新仓库
2、用 ELRepo 仓库
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
3、查看可用的系统内核包(可以看到，只有 4.4 和 4.20 两个版本可以使用)
[root@localhost ~]# yum --disablerepo="*" --enablerepo="elrepo-kernel" list available
已加载插件：fastestmirror, langpacks
Loading mirror speeds from cached hostfile
* elrepo-kernel: mirrors.neusoft.edu.cn
elrepo-kernel | 2.9 kB 00:00:00
elrepo-kernel/primary_db | 1.8 MB 00:00:01
可安装的软件包
kernel-lt.x86_64 4.4.169-1.el7.elrepo elrepo-kernel
kernel-lt-devel.x86_64 4.4.169-1.el7.elrepo elrepo-kernel
kernel-lt-doc.noarch 4.4.169-1.el7.elrepo elrepo-kernel
kernel-lt-headers.x86_64 4.4.169-1.el7.elrepo elrepo-kernel
kernel-lt-tools.x86_64 4.4.169-1.el7.elrepo elrepo-kernel
kernel-lt-tools-libs.x86_64 4.4.169-1.el7.elrepo elrepo-kernel
kernel-lt-tools-libs-devel.x86_64 4.4.169-1.el7.elrepo elrepo-kernel
kernel-ml.x86_64 4.20.0-1.el7.elrepo elrepo-kernel
kernel-ml-devel.x86_64 4.20.0-1.el7.elrepo elrepo-kernel
kernel-ml-doc.noarch 4.20.0-1.el7.elrepo elrepo-kernel
kernel-ml-headers.x86_64 4.20.0-1.el7.elrepo elrepo-kernel
kernel-ml-tools.x86_64 4.20.0-1.el7.elrepo elrepo-kernel
kernel-ml-tools-libs.x86_64 4.20.0-1.el7.elrepo elrepo-kernel
kernel-ml-tools-libs-devel.x86_64 4.20.0-1.el7.elrepo elrepo-kernel
perf.x86_64 4.20.0-1.el7.elrepo elrepo-kernel
python-perf.x86_64 4.20.0-1.el7.elrepo elrepo-kerne
4、安装最新内核
yum --enablerepo=elrepo-kernel install kernel-ml
二、设置grub2
1.查看系统上的所有可以内核
[root@localhost ~]# awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg
0 : CentOS Linux (4.20.0-1.el7.elrepo.x86_64) 7 (Core)
1 : CentOS Linux (3.10.0-957.1.3.el7.x86_64) 7 (Core)
2 : CentOS Linux (3.10.0-862.el7.x86_64) 7 (Core)
3 : CentOS Linux (0-rescue-87b5a0a60fc351ad00a94aa3c5b30baa) 7 (Core)
2.设置 grub2,并生成grub配置文件
[root@localhost ~]# grub2-set-default 0
[root@localhost ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.20.0-1.el7.elrepo.x86_64
Found initrd image: /boot/initramfs-4.20.0-1.el7.elrepo.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-957.1.3.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-957.1.3.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-862.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-87b5a0a60fc351ad00a94aa3c5b30baa
Found initrd image: /boot/initramfs-0-rescue-87b5a0a60fc351ad00a94aa3c5b30baa.img
done
3.重启并查看当前内核
[root@localhost ~]# reboot
[root@localhost ~]# uname -r
4.20.0-1.el7.elrepo.x86_64