1、Wget安装

Redhat7.3最小安装wget命令也需要自己安装一下，wget下载地址：http://mirrors.163.com/centos/7/os/x86_64/Packages/wget-1.14-18.el7_6.1.x86_64.rpm

下载到/usr/local/soft目录后，执行rpm -ivh wget-1.14-18.el7_6.1.x86_64.rpm安装。

2、Yum必须的rpm文件下载

进入/usr/local目录，创建一个soft文件夹，将安装yum所需要的包下载到soft文件夹下。

wget https://vault.centos.org/7.3.1611/os/x86_64/Packages/python-iniparse-0.4-9.el7.noarch.rpm
wget https://vault.centos.org/7.3.1611/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm
wget https://vault.centos.org/7.3.1611/os/x86_64/Packages/yum-3.4.3-150.el7.centos.noarch.rpm
wget https://vault.centos.org/7.3.1611/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget https://vault.centos.org/7.3.1611/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-40.el7.noarch.rpm

3、卸载系统自带的yum相关安装

3.1 查看原来是否安装yum： rpm -qa | grep yum

3.2 直接卸载自带的yum： rpm -qa|grep yum|xargs rpm -e --nodeps

3.3 查看是否卸载干净： rpm -qa |grep yum

4、安装centos源yum

依次安装之前下载的5个rpm文件

rpm -ivh python-iniparse-0.4-9.el7.noarch.rpm
rpm -ivh python-urlgrabber-3.10-8.el7.noarch.rpm
rpm -ivh yum-3.4.3-150.el7.centos.noarch.rpm --force --nodeps
rpm -ivh yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
rpm -ivh yum-plugin-fastestmirror-1.1.31-40.el7.noarch.rpm --force --nodeps

5、rhel-source.repo配置

编辑rhel-source.repo文件

编辑命令：vi /etc/yum.repos.d/rhel-source.repo，将文件原内容清空，替换为下面的内容

# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the 
# remarked out baseurl= line instead.
#
#

[base]
name=CentOS-$releasever - Base - 163.com
baseurl=http://mirrors.163.com/centos/7/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-7

6、卸载subscription-manager

查看subscription-manager版本： rpm -qa | grep subscription-manager

卸载subscription-manager：rpm -e subscription-manager-1.1.23-1.el6.x86_64

7、yum验证

清除缓存： yum clean all

测试，再次安装rzsz命令：yum -y install lrzsz，执行成功。

建立元数据缓存：yum makecache