本文以centos 8.0为例，内核版本为4.18.0-80.el8.x86_64，升级到内核版本为4.18.0-80.4.2.el8_0.x86_64。
1.查看当前系统版本信息
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[root@centos80-1905 ~]# uname -sr
Linux 4.18.0-80.el8.x86_642.在网站：https://vault.centos.org/里面下载Binary package二进制包
路径为：https://vault.centos.org/8.0.1905/BaseOS/x86_64/os/Packages/
3.按Ctrl+f在页面上进行查找，输入kernel，一路回车，找到你需要的kernel版本。
这里我需要的是4.18.0-80.4.2.el8_0.x86_64，点击，对应的rpm包就被下载到电脑上了。
4.将三个rpm包上传到centos 8系统中。
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total 45028
-rw-------. 1 root root 1274 May 30 2023 anaconda-ks.cfg
-rw-r--r--. 1 root root 419544 Aug 13 16:45 kernel-4.18.0-80.4.2.el8_0.x86_64.rpm
-rw-r--r--. 1 root root 24766716 Aug 13 16:46 kernel-core-4.18.0-80.4.2.el8_0.x86_64.rpm
-rw-r--r--. 1 root root 20912504 Aug 13 16:54 kernel-modules-4.18.0-80.4.2.el8_0.x86_64.rpm5.安装rpm包
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[root@centos80-1905 ~]# yum install kernel-*
Failed to set locale, defaulting to C
CentOS-8 - Extras 0.0 B/s | 0 B 00:01
Failed to synchronize cache for repo 'extras', ignoring this repo.
Last metadata expiration check: 0:08:50 ago on Tue Aug 13 16:45:45 2024.
Dependencies resolved.
=====================================================================================================================================================================
Package Arch Version Repository Size
=====================================================================================================================================================================
Installing:
kernel x86_64 4.18.0-80.4.2.el8_0 @commandline 410 k
kernel-core x86_64 4.18.0-80.4.2.el8_0 @commandline 24 M
kernel-modules x86_64 4.18.0-80.4.2.el8_0 @commandline 20 M
Transaction Summary
=====================================================================================================================================================================
Install 3 Packages
Total size: 44 M
Installed size: 76 M
Is this ok [y/N]: y
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : kernel-core-4.18.0-80.4.2.el8_0.x86_64 1/3
Running scriptlet: kernel-core-4.18.0-80.4.2.el8_0.x86_64 1/3
Installing : kernel-modules-4.18.0-80.4.2.el8_0.x86_64 2/3
Running scriptlet: kernel-modules-4.18.0-80.4.2.el8_0.x86_64 2/3
Installing : kernel-4.18.0-80.4.2.el8_0.x86_64 3/3
Running scriptlet: kernel-core-4.18.0-80.4.2.el8_0.x86_64 3/3
Running scriptlet: kernel-4.18.0-80.4.2.el8_0.x86_64 3/3
Verifying : kernel-4.18.0-80.4.2.el8_0.x86_64 1/3
Verifying : kernel-core-4.18.0-80.4.2.el8_0.x86_64 2/3
Verifying : kernel-modules-4.18.0-80.4.2.el8_0.x86_64 3/3
Installed:
kernel-4.18.0-80.4.2.el8_0.x86_64 kernel-core-4.18.0-80.4.2.el8_0.x86_64 kernel-modules-4.18.0-80.4.2.el8_0.x86_64
Complete!6.重启系统，查看系统内核是否升级成功。
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[root@centos80-1905 ~]# reboot
[root@centos80-1905 ~]# uname -sr
Linux 4.18.0-80.4.2.el8_0.x86_64