1、centos版本
CentOS Linux release 7.5.1804 (Core)
2、卸載原來的yum
[root@promote 下載]# rpm -qa|grep yum
yum-3.4.3-158.el7.centos.noarch
yum-utils-1.1.31-45.el7.noarch
PackageKit-yum-1.1.5-1.el7.centos.x86_64
yum-langpacks-0.4.2-7.el7.noarch
yum-metadata-parser-1.1.4-10.el7.x86_64
yum-plugin-fastestmirror-1.1.31-45.el7.noarch
[root@promote 下載]# rpm -e --nodeps yum-3.4.3-158.el7.centos.noarch
[root@promote 下載]# rpm -e --nodeps yum-utils-1.1.31-45.el7.noarch
[root@promote 下載]# rpm -e --nodeps PackageKit-yum-1.1.5-1.el7.centos.x86_64
[root@promote 下載]# rpm -e --nodeps yum-langpacks-0.4.2-7.el7.noarch
警告：/etc/yum/pluginconf.d/langpacks.conf 已另存爲 /etc/yum/pluginconf.d/langpacks.conf.rpmsave
[root@promote 下載]# rpm -e --nodeps yum-langpacks-0.4.2-7.el7.noarch
錯誤：未安裝軟件包 yum-langpacks-0.4.2-7.el7.noarch
[root@promote 下載]# rpm -e --nodeps yum-metadata-parser-1.1.4-10.el7.x86_64
[root@promote 下載]# rpm -e --nodeps yum-plugin-fastestmirror-1.1.31-45.el7.noarch
[root@promote 下載]# rpm -qa|grep yum
[root@promote 下載]# mkdir /tmp/yum-packages
[root@promote 下載]# cd /tmp/yum-packages/
3、從華爲雲下載yum的包
wget https://mirrors.huaweicloud.com/centos/7.5.1804/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget https://mirrors.huaweicloud.com/centos/7.5.1804/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm
wget https://mirrors.huaweicloud.com/centos/7.5.1804/os/x86_64/Packages/yum-3.4.3-158.el7.centos.noarch.rpm
wget https://mirrors.huaweicloud.com/centos/7.5.1804/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget https://mirrors.huaweicloud.com/centos/7.5.1804/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-45.el7.noarch.rpm
4、下載到當前包後
rpm -ivh --force --nodeps *.rpm
--force 強制安裝 --nodeps 覆蓋安裝
5、安裝完畢後
備份配置文件：cp -a /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
修改CentOS-Base.repo文件，取消baseurl開頭的行的註釋，並增加mirrorlist開頭的行的註釋。將文件中的http://mirror.centos.org替換成https://mirrors.huaweicloud.com，可以參考如下命令：
sed -i "s/#baseurl/baseurl/g" /etc/yum.repos.d/CentOS-Base.repo
sed -i "s/mirrorlist=http/#mirrorlist=http/g" /etc/yum.repos.d/CentOS-Base.repo
sed -i "s@http://mirror.centos.org@https://mirrors.huaweicloud.com@g" /etc/yum.repos.d/CentOS-Base.repo
執行yum clean all；yum makecache生成緩存
遇到的問題：
File contains no section headers.
file: file:///etc/yum.repos.d/google-chrome.repo, line: 2
'ogle-chrome]\n'
打開google-chrome.repo缺少一個“[”符號