redhat 的更新包只对注册的用户生效，所以我们需要自己手动更改成CentOS 的更新包，CentOS几乎和redhat是一样的，所以无需担心软件包
redhat 的更新包只对注册的用户生效，所以我们需要自己手动更改成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/7.3.1611/os/x86_64/Packages/yum-3.4.3-150.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7.3.1611/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget http://mirrors.163.com/centos/7.3.1611/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7.3.1611/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-40.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-$releasever - Base
baseurl=http://mirrors.163.com/centos/7.3.1611/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/7.3.1611/os/x86_64/RPM-GPG-KEY-CentOS-7
name=CentOS-$releasever - Updates
baseurl=http://mirrors.163.com/centos/7.3.1611/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/7.3.1611/os/x86_64/RPM-GPG-KEY-CentOS-7
name=CentOS-$releasever - Extras
baseurl=http://mirrors.163.com/centos/7.3.1611/extras//$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/7.3.1611/os/x86_64/RPM-GPG-KEY-CentOS-7
[centosplus]
name=CentOS-$releasever - Plus
baseurl=http://mirrors.163.com/centos/7.3.1611/centosplus//$basearch/
gpgcheck=1
enabled=0
5、 yum clean all
6、 yum update 测试。
7、 安装 epel 源
yum install epel-release
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