报错情况：
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
一、升级或卸载Python导致：
1、查看已安装python的版本，可能是当前系统存在多个python导致[root@test ~]# whereis pythonpython: /usr/bin/python2.6 /usr/bin/python /usr/bin/python2.6-config /usr/lib/python2.6 /usr/lib64/python2.6 /usr/include/python2.6 /usr/share/man/man1/python.1.gz[root@test ~]# vi /usr/bin/yum将 #!/usr/bin/python 修改为 #!/usr/bin/python2.6如果是源代码安装的，默认路径是/usr/local/bin/python2.6,做个软链接即可rm -rf /usr/bin/pythonln -s /usr/local/bin/python2.6 /usr/bin/python 二、完全重装python和yum
1、删除现有Python[root@test ~]# rpm -qa|grep python|xargs rpm -ev --allmatches --nodeps ##强制删除已安装程序及其关联[root@test ~]# 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[root@test ~]# whereis python ##验证删除，返回无结果2、删除现有的yum[root@test ~]# rpm -qa|grep yum|xargs rpm -ev --allmatches --nodeps[root@test ~]# whereis yum |xargs rm -frv3、从http://mirrors.ustc.edu.cn/centos/7.4.1708/os/x86_64/Packages/下载相应的包python-2.6.6-36.el6.x86_64.rpmpython-devel-2.6.6-36.el6.x86_64.rpmpython-libs-2.6.6-36.el6.x86_64.rpmpython-pycurl-7.19.0-8.el6.x86_64.rpmpython-setuptools-0.6.10-3.el6.noarch.rpmpython-urlgrabber-3.9.1-8.el6.noarch.rpm python-iniparse-0.3.1-2.1.el6.noarch.rpmrpm-python-4.8.0-32.el6.x86_64.rpmyum-3.2.29-40.el6.centos.noarch.rpmyum-metadata-parser-1.1.2-16.el6.x86_64.rpmyum-utils-1.1.30-14.el6.noarch.rpmyum-plugin-fastestmirror-1.1.30-14.el6.noarch.rpm yum-plugin-protectbase-1.1.30-14.el6.noarch.rpmyum-plugin-aliases-1.1.30-14.el6.noarch.rpmpython-backports-ssl_match_hostname
python-backports-
libxml2-python
python-kitchen
python-chardet
[root@test ~]# rpm -Uvh --replacepkgs libxml2-python*.rpm[root@test ~]# rpm -Uvh --replacepkgs python*.rpm[root@test ~]# rpm -Uvh --replacepkgs rpm-python*.rpm yum*.rpm