环境介绍
线上环境运行centos 内核版本规定为：
CentOS Linux release 7.3.1611 (Core)
查看内核版本参考命令：
[root@localhost ~]# cat /etc/redhat-release
CentOS Linux release 7.3.1611 (Core)
[root@localhost ~]# uname -a
Linux localhost.localdomain 3.10.0-514.el7.x86_64 #1 SMP Tue Nov 22 16:42:41 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost ~]# rpm -qa |grep -i centos-release
centos-release-7-3.1611.el7.centos.x86_64
问题描述
安装MySQL 时候，升级系统软件包，顺手升级了内核版本；
[root@localhost ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
操作目的
降级目前操作系统内核版本7.4为7.3
操作步骤
网上搜索下载centos-release文件地址已失效；
在此，采用解压安装镜像，然后拷贝安装软件包到目的服务器方式；
#将软件包上传至需要降级服务器；
[root@localhost ~]# ls
centos-release-7-3.1611.el7.centos.x86_64.rpm
#查看当前运行内核版本
[root@localhost boot]# uname -a
Linux localhost.localdomain 3.10.0-514.26.2.el7.x86_64 #1 SMP Tue Jul 4 15:04:05 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
#查看已安装内核版本
[root@localhost boot]# rpm -qa |grep kernel
kernel-3.10.0-514.el7.x86_64
kernel-tools-libs-3.10.0-693.5.2.el7.x86_64
kernel-tools-3.10.0-693.5.2.el7.x86_64
kernel-3.10.0-693.5.2.el7.x86_64
kernel-3.10.0-514.26.2.el7.x86_64
#卸载新版本内核
[root@localhost boot]# rpm -e kernel-3.10.0-514.el7.x86_64
#查看卸载后安装内核版本信息
[root@localhost boot]# rpm -qa |grep kernel
kernel-tools-libs-3.10.0-693.5.2.el7.x86_64
kernel-tools-3.10.0-693.5.2.el7.x86_64
kernel-3.10.0-693.5.2.el7.x86_64
kernel-3.10.0-514.26.2.el7.x86_64
#卸载内核附加文件
[root@localhost boot]# rpm -e kernel-3.10.0-514.26.2.el7.x86_64
#查看卸载后安装内核版本信息，已完全卸载
[root@localhost boot]# rpm -qa |grep kernel
kernel-tools-libs-3.10.0-693.5.2.el7.x86_64
kernel-tools-3.10.0-693.5.2.el7.x86_64
kernel-3.10.0-693.5.2.el7.x86_64
#查看内核发行版信息，此处仍未新版本7.4，需要降低发行版信息
[root@localhost ~]# rpm -qa |grep -i centos-release
centos-release-7-4.1708.el7.centos.x86_64
centos-release-7-3.1611.el7.centos.x86_64
#安装内核发行版rpm包，此rpm包网上没找到下载地址，直接解压了安装镜像，从安装包文件夹中导入服务器安装即可
[root@localhost ~]# rpm -ivh centos-release-7-3.1611.el7.centos.x86_64.rpm --force
Preparing... ################################# [100%]
Updating / installing...
1:centos-release-7-3.1611.el7.cento################################# [100%]
#查看已安装内核发行版信息
[root@localhost ~]# rpm -qa |grep -i centos-release
centos-release-7-4.1708.el7.centos.x86_64
centos-release-7-3.1611.el7.centos.x86_64
#卸载7.4内核发行版rpm包
[root@localhost ~]# rpm -ev centos-release-7-4.1708.el7.centos.x86_64
Preparing packages...
centos-release-7-4.1708.el7.centos.x86_64
#查看卸载后目前内核发行版rpm包信息为7.3
[root@localhost ~]# rpm -qa |grep -i centos-release
centos-release-7-3.1611.el7.centos.x86_64
#重启服务器
[root@localhost ~]# reboot
#查看目前内核发行版信息，内核版本为7.3，卸载成功
[root@localhost ~]# cat /etc/redhat-release
CentOS Linux release 7.3.1611 (Core)
[root@localhost ~]# uname -a
Linux localhost.localdomain 3.10.0-693.5.2.el7.x86_64 #1 SMP Fri Oct 20 20:32:50 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux