環境介紹
線上環境運行centos 內核版本規定爲：
CentOS Linux release 7.3.1611 (Core)
查看內核版本參考命令：
[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
問題描述
安裝MySQL 時候，升級系統軟件包，順手升級了內核版本；
[root@localhost ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
操作目的
降級目前操作系統內核版本7.4爲7.3
操作步驟
網上搜索下載centos-release文件地址已失效；
在此，採用解壓安裝鏡像，然後拷貝安裝軟件包到目的服務器方式；
#將軟件包上傳至需要降級服務器；
[root@localhost ~]# ls
centos-release-7-3.1611.el7.centos.x86_64.rpm
#查看當前運行內核版本
[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
#查看已安裝內核版本
[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
#卸載新版本內核
[root@localhost boot]# rpm -e kernel-3.10.0-514.el7.x86_64
#查看卸載後安裝內核版本信息
[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
#卸載內核附加文件
[root@localhost boot]# rpm -e kernel-3.10.0-514.26.2.el7.x86_64
#查看卸載後安裝內核版本信息，已完全卸載
[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
#查看內核發行版信息，此處仍未新版本7.4，需要降低發行版信息
[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
#安裝內核發行版rpm包，此rpm包網上沒找到下載地址，直接解壓了安裝鏡像，從安裝包文件夾中導入服務器安裝即可
[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%]
#查看已安裝內核發行版信息
[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
#卸載7.4內核發行版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
#查看卸載後目前內核發行版rpm包信息爲7.3
[root@localhost ~]# rpm -qa |grep -i centos-release
centos-release-7-3.1611.el7.centos.x86_64
#重啓服務器
[root@localhost ~]# reboot
#查看目前內核發行版信息，內核版本爲7.3，卸載成功
[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