1. 查看centos 的版本号
cat /etc/redhat-release
2. 进入阿里云源站地址：http://mirrors.aliyun.com/ 找到对应的版本号
3.下载相应的yum包
wget https://mirrors.aliyun.com/centos/7.7.1908/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm wget https://mirrors.aliyun.com/centos/7.7.1908/os/x86_64/Packages/yum-3.4.3-163.el7.centos.noarch.rpm wget https://mirrors.aliyun.com/centos/7.7.1908/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-52.el7.noarch.rpm
4. 执行下面命令
rpm -ivh yum-metadata-parser-1.1.4-10.el7.x86_64.rpm rpm -ivh yum-3.4.3-163.el7.centos.noarch.rpm yum-plugin-fastestmirror-1.1.31-52.el7.noarch.rpm
5. 测试
