redhat 的更新包只对注册的用户生效，所以我们自己手动更改成CentOS 的更新包，CentOS几乎和redhat是一样的，所以无需担心软件包是否可安装，安装之后是否有问题。
1、首先删除redhat原有的yum ，因为redhat 原本的yum 没有注册为redhat用户是用不了的。

rpm -aq|grep yum|xargs rpm -e --nodeps 
rpm -aq|grep python-iniparse|xargs rpm -e --nodeps

2、下载163的yum 安装包

# wget http://mirrors.163.com/centos/7.2.1511/os/x86_64/Packages/yum-3.4.3-132.el7.centos.0.1.noarch.rpm# wget http://mirrors.163.com/centos/7.2.1511/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm   # wget http://mirrors.163.com/centos/7.2.1511/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm # wget http://mirrors.163.com/centos/7.2.1511/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-34.el7.noarch.rpm

3、安装下载的rpm包

rpm -ivh *.rpm

4、创建文件/etc/yum.repos.d/rhel-debuginfo.repo并写入

[base]
name=CentOS-$releasever - Basebaseurl=http://mirrors.163.com/centos/7.2.1511/os/$basearch/gpgcheck=1gpgkey=http://mirrors.163.com/centos/7.2.1511/os/x86_64/RPM-GPG-KEY-CentOS-7#released updates[updates]
name=CentOS-$releasever - Updatesbaseurl=http://mirrors.163.com/centos/7.2.1511/updates/$basearch/gpgcheck=1gpgkey=http://mirrors.163.com/centos/7.2.1511/os/x86_64/RPM-GPG-KEY-CentOS-7[extras]
name=CentOS-$releasever - Extrasbaseurl=http://mirrors.163.com/centos/7.2.1511/extras//$basearch/
gpgcheck=1gpgkey=http://mirrors.163.com/centos/7.2.1511/os/x86_64/RPM-GPG-KEY-CentOS-7[centosplus]
name=CentOS-$releasever - Plusbaseurl=http://mirrors.163.com/centos/7.2.1511/centosplus//$basearch/
gpgcheck=1enabled=0

5、 yum clean all
6、 yum makecache

7、 安装 epel 源

# yum install epel-release