1. Check the version number of centos
cat /etc/redhat-release
2. Ali cloud into the source station address: http: //mirrors.aliyun.com/ find the corresponding version number
3. download the appropriate package yum
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. Run the following commands
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. Test
