RedHat yum源是收费的，没有注册的Redhat机器是不能使用yum源的。

1、当前系统环境：

系统版本：Red Hat Enterprise Linux Server release 7.3 (Maipo)

软件环境：系统默认是自带了yum程序的，需要卸载，安装CentOS的

2、更换yum源：

1) 卸载本地yum:

# rpm -qa|grep yum    　　#查看本地yum

# rpm -qa|grep yum|xargs rpm -e --nodeps     　　#卸载本地yum，不检查依赖性，卸载yum程序

# rpm -qa | grep Python-urlgrabber | xargs rpm -e --nodeps

2) 下载CentOS yum程序

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-161.el7.centos.noarch.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-50.el7.noarch.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm

使用wget命令下载，也可以用浏览器下载。rpm包下载地址http://mirrors.163.com/centos/7/os/x86_64/Packages/ ，包的版本会有更新，选择最新版本下载

安装CentOS yum程序

为避免他们之间互相依赖，三个程序一起安装

# rpm -ivh yum-3.4.3-161.el7.centos.noarch.rpm yum-plugin-fastestmirror-1.1.31-50.el7.noarch.rpm yum-metadata-parser-1.1.4-10.el7.x86_64.rpm

安装报错，依赖软件版本不兼容，

警告：yum-3.4.3-161.el7.centos.noarch.rpm: 头V3 RSA/SHA256 Signature, 密钥 ID f4a80eb5: NOKEY

错误：依赖检测失败：

python-urlgrabber >= 3.10-8 被 yum-3.4.3-161.el7.centos.noarch 需要

rpm >= 0:4.11.3-22 被 yum-3.4.3-161.el7.centos.noarch 需要

重新下载新版本的依赖软件，安装更新

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-35.el7.x86_64.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-libs-4.11.3-35.el7.x86_64.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-build-libs-4.11.3-35.el7.x86_64.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-python-4.11.3-35.el7.x86_64.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/python-chardet-2.2.1-1.el7_1.noarch.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/python-kitchen-1.1.1-5.el7.noarch.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/python-urlgrabber-3.10-9.el7.noarch.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/libxml2-python-2.9.1-6.el7_2.3.x86_64.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-35.el7.x86_64.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-sign-4.11.3-35.el7.x86_64.rpm

#  wget  http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-build-4.11.3-35.el7.x86_64.rpm

更新依赖软件：

# rpm –ivh python-*

# rpm -ivh libxml*

# rpm –Uvh rpm*

再次安装yum程序

# rpm -ivh yum-3.4.3-161.el7.centos.noarch.rpm yum-plugin-fastestmirror-1.1.31-50.el7.noarch.rpm yum-metadata-parser-1.1.4-10.el7.x86_64.rpm

安装报错：

错误：依赖检测失败：

python-urlgrabber >= 3.10-8 被 yum-3.4.3-161.el7.centos.noarch 需要

Python-urlgrabber版本不兼容，下载对应的版本。

#  wget  ftp://ftp.icm.edu.pl/vol/rzm3/linux-centos-altarch/7.5.1804/os/armhfp/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm

安装：

# rpm -ivh python-urlgrabber-3.10-8.el7.noarch.rpm

再次安装yum程序

# rpm -ivh yum-3.4.3-161.el7.centos.noarch.rpm yum-plugin-fastestmirror-1.1.31-50.el7.noarch.rpm yum-metadata-parser-1.1.4-10.el7.x86_64.rpm

安装成功。

3) repo 配置文件

下载配置文件

#  cd /etc/yum.repos.d/　　#进入到yum配置文件目录

#  wget http://mirrors.163.com/.help/CentOS7-Base-163.repo    #下载配置文件

设置配置文件

# sed -i "s;\$releasever;7;g" CentOS7-Base-163.repo

替换新的repo文件

# mv redhat.repo redhat.repo.bak

配置文件内容如下：

[base]

name=CentOS-7 - Base - 163.com

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os

baseurl=http://mirrors.163.com/centos/7/os/$basearch/

gpgcheck=1

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

#released updates

[updates]

name=CentOS-7 - Updates - 163.com

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates

baseurl=http://mirrors.163.com/centos/7/updates/$basearch/

gpgcheck=1

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful

[extras]

name=CentOS-7 - Extras - 163.com

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras

baseurl=http://mirrors.163.com/centos/7/extras/$basearch/

gpgcheck=1

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages

[centosplus]

name=CentOS-7 - Plus - 163.com

baseurl=http://mirrors.163.com/centos/7/centosplus/$basearch/

gpgcheck=1

enabled=0

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

更新yum缓存

# yum clean all　　#清除yum缓存

# yum makecache  　　#更新yum缓存

执行yumrepolist查看，如果显示出repo仓库列表，并显示软件包数量则OK。

#  yum  repolist

至此yum源更换完成。