由于Redhat的yum在线更新是收费的，如果没有注册的话是不能使用的，即不能在线安装软件。在这种情况下，想使用Redhat系统，还想用yum源来在线安装软件，有没有办法？
　　答案是有办法，请往下看！
原文 http://blog.itpub.net/23890223/viewspace-757724/

1、首先查看redhat 7.0系统本身所安装的那些yum 软件包：
[root@localhost ~]# rpm -qa | grep yum
yum-utils-1.1.31-24.el7.noarch
yum-langpacks-0.4.2-3.el7.noarch
yum-metadata-parser-1.1.4-10.el7.x86_64
yum-rhn-plugin-2.0.1-4.el7.noarchPackageKit-
yum-0.8.9-11.el7.x86_64
yum-3.4.3-118.el7.noarch
2、删除这些软件包；
[root@localhost ~]# rpm -e yum-3.4.3-118.el7.noarch --nodeps
[root@localhost ~]# rpm -e yum-utils-1.1.31-24.el7.noarch --nodeps
[root@localhost ~]# rpm -e yum-rhn-plugin-2.0.1-4.el7.noarch --nodeps
[root@localhost ~]# rpm -e yum-metadata-parser-1.1.4-10.el7.x86_64 --nodeps
[root@localhost ~]# rpm -e yum-langpacks-0.4.2-3.el7.noarch --nodeps
[root@localhost ~]# rpm -e PackageKit-yum-0.8.9-11.el7.x86_64 --nodeps

4、进入以下网站上面查看软件包的版本是否升级或者找到自己系统所对应的文件包版本更新；
网易163网络源地址：http://mirrors.163.com/CentOS
网络源地址：http://centos.ustc.edu.cn/centos/

5、找到自己所需要的版本下载：
[root@localhost ~]# wget http://mirrors.163.com/centos/7.1.1503/os/x86_64/Packages/yum-3.4.3-118.el7.centos.noarch.rpm
[root@localhost ~]# wget http://mirrors.163.com/centos/7.1.1503/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
[root@localhost ~]# wget http://mirrors.163.com/centos/7.1.1503/os/x86_64/Packages/yum-utils-1.1.31-24.el7.noarch.rpm
[root@localhost ~]# wget http://mirrors.163.com/centos/7.1.1503/os/x86_64/Packages/yum-updateonboot-1.1.31-24.el7.noarch.rpm
[root@localhost ~]# wget http://mirrors.163.com/centos/7.1.1503/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-24.el7.noarch.rpm

6、查看下载完成结果；
[root@localhost ~]# ls
yum-3.4.3-125.el7.centos.noarch.rpm
yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
yum-plugin-fastestmirror-1.1.31-29.el7.noarch.rpm
yum-updateonboot-1.1.31-29.el7.noarch.rpm
yum-utils-1.1.31-29.el7.noarch.rpm

7、安装软件包：
[root@localhost ~]# rpm -ivh yum-*
warning: yum-3.4.3-118.el7.centos.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEYPreparing... ################################# [100%]Updating / installing...
1:yum-metadata-parser-1.1.4-10.el7 ################################# [ 20%] 2:yum-plugin-fastestmirror-1.1.31-2################################# [ 40%] 3:yum-3.4.3-118.el7.centos ################################# [ 60%] 4:yum-updateonboot-1.1.31-24.el7 ################################# [ 80%] 5:yum-utils-1.1.31-24.el7 ################################# [100%

8、新建repo 配置文件；
[root@localhost ~]# vim /etc/yum.repos.d/CentOS-Base.repo
[base]
name=CentOS-$releasever - Base - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://mirrors.163.com/centos/7.1.1503/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
#released updates
[updates]
name=CentOS-$releasever - Updates - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://mirrors.163.com/centos/7.1.1503/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://mirrors.163.com/centos/7.1.1503/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
#additional packages that extendfunctionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - 163.com
baseurl=http://mirrors.163.com/centos/7.1.1503/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

9、至此YUM 网络源已经安装完成；
[root@localhost~]
# yum clean all #
清理yum缓存
[root@localhost ~]
# yum makecache #
将服务器上的软件包信息缓存到本地,以提高搜索安装软件的速度
[root@localhost ~]
# yum install vim* #
测试域名是否可用

关于安装yum mysql
1、首先查看卸载系统本身所安装的那些mysql 软件包：
[root@localhost ~]#rpm -qa | grep mysql
[root@localhost ~]#rpm -e 上面列出的包名 --nodeps
2、打开mysql官网
找到 Download 点击 Yum Repository 下拉找到 Red Hat Enterprise Linux 7 / Oracle Linux 7 (Architecture Independent), RPM Package 下载
3、安装下载的文件
[root@localhost ~]#rpm -ivh mysql-community-release-el7-5.noarch.rpm
4丶愉快的下载
[root@localhost ~]#yum install mysql

到这里怎么选择下载文件呢，谢谢

您可以尝试添加 --skip-broken 选项来解决该问题
** 发现 2 个已存在的 RPM 数据库问题， 'yum check' 输出如下：
PackageKit-0.8.9-11.el7.x86_64 有缺少的需求 PackageKit-backend
rhn-check-2.0.2-6.el7.noarch 有缺少的需求 yum-rhn-plugin >= ('0', '1.6.4', '1')
[root@localhost ~]# yum check
已加载插件：fastestmirror, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
PackageKit-0.8.9-11.el7.x86_64 有缺少的需求 PackageKit-backend
rhn-check-2.0.2-6.el7.noarch 有缺少的需求 yum-rhn-plugin >= ('0', '1.6.4', '1')
错误：check all
[root@localhost ~

完全没必要搞这么麻烦，直接用就可

那为啥不直接centos就行，它们两个没区别

python-urlgrabber >= 3.10-8 is needed by yum-3.4.3-150.el7.centos.noarch
python-kitchen is needed by yum-utils-1.1.31-40.el7.noarch

这是什么情况？