查看已安装的yum
rpm -qa|grep yum
删除已有的yum
rpm -aq|grep yum|xargs rpm -e --nodeps
下载yum
wget --no-check-certificate https://vault.centos.org/6.9/os/i386/Packages/yum-metadata-parser-1.1.2-16.el6.i686.rpm wget --no-check-certificate https://vault.centos.org/6.9/os/i386/Packages/yum-3.2.29-81.el6.centos.noarch.rpm wget --no-check-certificate https://vault.centos.org/6.9/os/i386/Packages/yum-plugin-fastestmirror-1.1.30-40.el6.noarch.rpm
安装yum
rpm -ivh yum-metadata-parser-1.1.2-16.el6.i686.rpm --nodeps --force yum包与yum-plgin-fastestmirror包要同时安装 rpm -ivh yum-3.2.29-81.el6.centos.noarch.rpm yum-plugin-fastestmirror-1.1.30-40.el6.noarch.rpm 这两步不能少 yum clean all yum makecache
更换CentOS Yum 源
wget http://mirrors.aliyun.com/repo/Centos-6.repo 要现备份下原来的yum源，然后替换当前系统的repo文件，输入下面的命令 cd /etc/yum.repos.d/ mv CentOS-base.repo CentOS-base.repo.bak mv /usr/local/src/yum/Centos-6.repo CentOS-base.repo
把文件中的 url 改为下列网址，版本号对应自己机器的版本号
name=CentOS-6.9 failovermethod=priority baseurl=https://vault.centos.org/6.9/os/i386/ gpgcheck=0
做好以上的工作之后，我们就可以来执行yum 更新了
sudo yum clean all sudo yum makecache sudo yum update
故障排查(思路)
检查yum的安装路径
whereis yum
检查python的安装路径
whereis python
检查系统调用按个版本的路径(如果机器上有多个python)
ll /usr/local/bin/
检查/usr/bin/目录下是否含有python的文件
需要将/usr/bin/python软连接到/usr/local/bin/ 目录下(如下图)
ln -s /usr/bin/python2.6 /usr/local/bin/python
ln -s /usr/bin/python2.6-config /usr/local/bin/python-config
