1.yum install xxx 提示 -bash: yum: command not found
解决办法： rpm -qa | grep yum
查看有无yum,有的话卸载 rpm -aq|grep yum|xargs rpm -e --nodeps
2.下载需要的4个yum安装文件 （http://mirrors.163.com/centos/6/os/x86_64/Packages/）
yum-3.2.29-81.el6.centos.noarch.rpm
yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
yum-plugin-fastestmirror-1.1.30-41.el6.noarch.rpm
python-iniparse-0.3.1-2.1.el6.noarch.rpm
3.下载（如果下载不了，可以自己下载后再上传）
1.wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-3.2.29-81.el6.centos.noarch.rpm
2.wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
3.wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.30-41.el6.noarch.rpm
4.wget http://mirrors.163.com/centos/6/os/x86_64/Packages/python-iniparse-0.3.1-2.1.el6.noarch.rpm
4.安装
rpm -ivh --force --nodeps python-iniparse-0.3.1-2.1.el6.noarch.rpm
rpm -ivh --force --nodeps yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
rpm -ivh --force --nodeps yum-3.2.29-81.el6.centos.noarch.rpm yum-plugin-fastestmirror-1.1.30-41.el6.noarch.rpm
注意：最后两个包必须痛还是安装，否则报依赖出错
5.配置yum 源
yum install -y wget 先安装wget为下载网络yum源做准备，有的话就不必装了
替换 yum源
1. cd /etc/yum.repos.d
2. 将原来的备份 mv yum.repo yum.repo.bak
3.下载阿里云的yum源 wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
4.下载后生成缓存 yum makecache
6.报错：This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register
[Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
解决办法：sed -i 's/\$releasever/6/' CentOS-Base.repo 后面的6代表的是rehat的 版本
重新生成缓存
yum clean all
yum makecache
7.查看yum源是否配置完成
yum repolist
数字不为0，就成功了