1.删除python及yum相关文件
2.从http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/下载并安装python和yum程序包及其依赖包
所有rpm包下载完成
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/lvm2-python-libs-2.02.177-4.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/libxml2-python-2.9.1-6.el7_2.3.x86_64.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-libs-2.7.5-68.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-ipaddress-1.0.16-2.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-backports-1.0-8.el7.x86_64.rpm
wgethttp://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-backports-ssl_match_hostname-3.5.0.1-1.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-2.7.5-68.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-pycurl-7.19.0-19.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-setuptools-0.9.8-7.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-kitchen-1.1.1-5.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/python-chardet-2.2.1-1.el7_1.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/rpm-python-4.11.3-32.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-utils-1.1.31-45.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-3.4.3-158.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-plugin-aliases-1.1.31-45.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-plugin-protectbase-1.1.31-45.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.5.1804/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-45.el7.noarch.rpm
rpm -Uvh --replacepkgs lvm2-python-libs*.rpm
rpm -Uvh --replacepkgs libxml2-python*.rpm
rpm -Uvh --replacepkgs python*.rpm
rpm -Uvh --replacepkgs rpm-python*.rpm yum*.rpm
若出现依赖错误rpm = 4.8.0-55.el6 is needed by rpm-python-4.8.0-55.el6.x86_64等
就强制安装，使用命令：rpm -i --force --nodeps 安装每一个包，就解决了；
3 测试
