删除现有Python
rpm -qa|grep python|xargs rpm -ev --allmatches --nodeps ##强制删除已安装程序及其关联
whereis python |xargs rm -frv ##删除所有残余文件 ##xargs，允许你对输出执行其他某些命令
whereis python ##验证删除，返回无结果
删除原有YUM
rpm -aq|grep yum|xargs rpm -e --nodeps
验证是否删除完成：whereis yum |xargs rm -frv
下载：
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/python-2.7.5-68.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/python-devel-2.7.5-68.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/python-libs-2.7.5-68.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/python-pycurl-7.19.0-19.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/python-setuptools-0.9.8-7.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/rpm-python-4.11.3-32.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-3.4.3-158.el7.centos.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-utils-1.1.31-45.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-45.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-plugin-protectbase-1.1.31-45.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-plugin-aliases-1.1.31-45.el7.noarch.rpm
wget http://mirrors.ustc.edu.cn/centos/7/os/x86_64/Packages/libxml2-python-2.9.1-6.el7_2.3.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/libxml2-python-2.9.1-6.el7_2.3.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-32.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-chardet-2.2.1-1.el7_1.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-kitchen-1.1.1-5.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-backports-ssl_match_hostname-3.5.0.1-1.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-backports-1.0-8.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-ipaddress-1.0.16-2.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.2.1511/os/x86_64/Packages/python-ipaddress-1.0.16-2.el7.noarch.rp
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/lvm2-python-libs-2.02.130-5.el7.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/libxml2-python-2.9.1-5.el7_1.2.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-libs-2.7.5-34.el7.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-backports-1.0-8.el7.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-backports-ssl_match_hostname-3.4.0.2-4.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-2.7.5-34.el7.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-pycurl-7.19.0-17.el7.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-urlgrabber-3.10-7.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-setuptools-0.9.8-4.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-kitchen-1.1.1-5.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/python-chardet-2.2.1-1.el7_1.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/rpm-python-4.11.3-17.el7.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-utils-1.1.31-34.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-3.4.3-132.el7.centos.0.1.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-plugin-aliases-1.1.31-34.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-plugin-protectbase-1.1.31-34.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-34.el7.noarch.rpm
wget http://rpmfind.net/linux/fedora/linux/releases/27/Everything/x86_64/os/Packages/l/lvm2-libs-2.02.173-4.fc27.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/rpm-4.11.3-17.el7.x86_64.rpm
安装：
rpm -ivh python-* rpm-python-* --nodeps --force
rpm -ivh yum-*