本主机是centos7.9,内核版本3.10.0-1160.el7.x86_64,我想升级到3.10.0-1160.11.1.el7.x86_64
3.10.0-1160.el7.x86_64 -> 3.10.0-1160.11.1.el7.x86_64

在阿里云下载这两个.rpm文件:
https://mirrors.aliyun.com/centos/7.9.2009/updates/x86_64/Packages/



对于rpm文件的下载,如果阿里云上没有可以去centos官网下载:
https://vault.centos.org/
输入以下命令:
rpm -ivh *.rpm --nodeps --force

查看/boot/目录下也会生成该内核版本的内核镜像等等

修改grub配置,输入:
vim /etc/default/grub

将#GRUB_DEFAULT=saved改为GRUB_DEFAULT=0
输入:
grub2-mkconfig -o /boot/grub2/grub.cfg

NAME
grub-mkconfig — Generate a GRUB configuration file.
SYNOPSIS
grub-mkconfig [-o | --output=FILE]
DESCRIPTION
grub-mkconfig generates a configuration file for GRUB.
然后重启选择3.10.0-1160.11.1.el7.x86_64版本。
查看结果升级成功:

查看系统存在的内核:
rpm -qa | grep kernel

删除内核:
yum remove kernel-3.10.0-1160.el7.x86_64

查看系统已有的小版本内核:
[root@localhost ~]# cat /boot/grub2/grub.cfg |grep menuentry
if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="--id"
menuentry_id_option=""
export menuentry_id_option
menuentry 'CentOS Linux (3.10.0-1160.53.1.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-1160.53.1.el7.x86_64-advanced-d724e29d-7d50-48a5-bde4-632302c85663' {
menuentry 'CentOS Linux (3.10.0-957.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-957.el7.x86_64-advanced-d724e29d-7d50-48a5-bde4-632302c85663' {
menuentry 'CentOS Linux (0-rescue-ebdbc7970af34a6a946652e7543cb802) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-ebdbc7970af34a6a946652e7543cb802-advanced-d724e29d-7d50-48a5-bde4-632302c85663' {
选择CentOS Linux (3.10.0-957.el7.x86_64) 7 (Core):
[root@localhost ~]# grub2-set-default 'CentOS Linux (3.10.0-957.el7.x86_64) 7 (Core)'
查看修改结果:
[root@localhost ~]# grub2-editenv list
saved_entry=CentOS Linux (3.10.0-957.el7.x86_64) 7 (Core)
重启:
reboot
修改成功:
[root@localhost ~]# uname -r
3.10.0-957.el7.x86_64