1.删除redhat原有的yum
rpm -aq|grep yum|xargs rpm -e --nodeps
2.下载yum安装文件
RHEL7
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-150.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-40.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
RHEL6.0
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-3.2.29-81.el6.centos.noarch.rpm
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.30-40.el6.noarch.rpm
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/python-iniparse-0.3.1-2.1.el6.noarch.rpm
wget http://mirrors.163.com/centos/6/os/x86_64/Packages/python-urlgrabber-3.9.1-11.el6.noarch.rpm
3.进行安装yum
rpm -ivh python-iniparse-0.4-9.el7.noarch.rpm
rpm -ivh yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
rpm -ivh yum-3.4.3-150.el7.centos.noarch.rpm yum-plugin-fastestmirror-1.1.31-40.el7.noarch.rpm
注意最后两个包必需同时安装，否则会相互依赖
4.更新repo文件
mv /etc/yum.repos.d/rhel-debuginfo.repo /etc/yum.repos.d/rhel-debuginfo.repo.repo.bak
vi /etc/yum.repos.d/rhel-debuginfo.repo
内容为：
[base]
name=CentOS-$releasever - Base
baseurl=http://mirrors.163.com/centos/7.3.1611/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=http://mirrors.163.com/centos/7.3.1611/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
#packages used/produced in the build but not released
#[addons]
#name=CentOS-$releasever - Addons
#baseurl=http://mirrors.163.com/centos/$releasever/addons/$basearch/
#gpgcheck=1
#gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=http://mirrors.163.com/centos/7.3.1611/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
baseurl=http://mirrors.163.com/centos/7.3.1611/centosplus/$basearch/
gpgcheck=1
enabled=0
5、若更新yum后仍会自动生成redhat.repo文件，提示未进行注册，则检查是否安装subscription-manager组件，如下：
1）查找RHN注册和订阅的程序组件。
(1) 查找subscription-manager相关组件:
执行命令: rpm -qa|grep subscription-manager
subscription-manager-gui-1.14.10-1.el6.x86_64
subscription-manager-1.14.10-1.el6.x86_64
subscription-manager-migration-1.14.10-1.el6.x86_64
subscription-manager-migration-data-2.0.22-1.el6.noarch
subscription-manager-firstboot-1.14.10-1.el6.x86_64
(2) 查找rhn相关组件:
执行命令: rpm -qa|grep rhn
rhnsd-4.9.3-2.el6.x86_64
rhn-check-1.0.0.1-32.el6.noarch
rhn-setup-gnome-1.0.0.1-32.el6.noarch
rhn-setup-1.0.0.1-32.el6.noarch
rhn-client-tools-1.0.0.1-32.el6.noarch
rhnlib-2.5.22-15.el6.noarch
yum-rhn-plugin-0.9.1-58.el6.noarch
2）删除subscription-manager和rhn的相关程序组件。
(1) 执行命令: yum remove subscription-manager
正在删除 : subscription-manager-firstboot-1.14.10-1.el6.x86_64 1/4
正在删除 : subscription-manager-migration-1.14.10-1.el6.x86_64 2/4
正在删除 : subscription-manager-gui-1.14.10-1.el6.x86_64 3/4
正在删除 : subscription-manager-1.14.10-1.el6.x86_64 4/4
(2) 执行命令: yum remove rhn-check
正在删除 : rhn-setup-gnome-1.0.0.1-32.el6.noarch 1/5
正在删除 : rhn-check-1.0.0.1-32.el6.noarch 2/5
正在删除 : yum-rhn-plugin-0.9.1-58.el6.noarch 3/5
正在删除 : rhn-setup-1.0.0.1-32.el6.noarch 4/5
正在删除 : rhnsd-4.9.3-2.el6.x86_64 5/5
注：这里不用rpm -e来删除程序是因为在执行删除任务的过程中会出现由于程序的相互依赖关系而无法删除的错误。
因此，用yum remove来执行删除任务，它会自动分析程序的相互依赖关系并删除。