redhat 的更新包只对注册的用户生效，所以我们自己手动更改成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，另外CentOS公司去年已经被Redhat 收购了，不说费话了，我们还是来操作吧！
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.noarch
PackageKit-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
3、本机电脑得能上网；
我下载好了网盘地址：http://pan.baidu.com/s/1hqqCEOG
[root@localhost ~]# ping 8.8.8.8PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=48 time=51.3 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=48 time=49.5 ms
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/os/x86_64/Packages/yum-3.4.3-118.el7.centos.noarch.rpm
[root@localhost ~]# wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
[root@localhost ~]# wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-utils-1.1.31-24.el7.noarch.rpm
[root@localhost ~]# wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-updateonboot-1.1.31-24.el7.noarch.rpm
[root@localhost ~]# wget http://mirrors.163.com/centos/7/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-3.4.3-118.el7.centos.noarch.rpm
yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
yum-plugin-fastestmirror-1.1.31-24.el7.noarch.rpm
yum-updateonboot-1.1.31-24.el7.noarch.rpm
yum-utils-1.1.31-24.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: NOKEY
Preparing... ################################# [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-$releasever -Base
baseurl=http://mirrors.sohu.com/centos/7/os/$basearch/
gpgcheck=1
#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=http://mirrors.163.com/centos/7/updates/$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/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/centosplus/$basearch/
gpgcheck=1
enabled=0
9、至此YUM 网络源已经安装完成；
[root@localhost ~]# yum clean all10、测试安装是否正常；
[root@localhost ~]# yum -y install zlib zlib-devel openssl openssl-devel pcre pcre-devel
Loaded plugins: fastestmirror, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Loading mirror speeds from cached hostfile
No package zlib-devel available.
No package pcre-devel available.
Resolving Dependencies
--> Running transaction check
---> Package openssl.x86_64 1:1.0.1e-34.el7 will be updated
---> Package openssl.x86_64 1:1.0.1e-34.el7_0.7 will be an update
--> Processing Dependency: openssl-libs(x86-64) = 1:1.0.1e-34.el7_0.7 for package: 1:openssl-1.0.1e-34.el7_0.7.x86_64
---> Package openssl-devel.x86_64 1:1.0.1e-34.el7_0.7 will be installed
--> Processing Dependency: zlib-devel(x86-64) for package: 1:openssl-devel-1.0.1e-34.el7_0.7.x86_64
--> Processing Dependency: krb5-devel(x86-64) for package: 1:openssl-devel-1.0.1e-34.el7_0.7.x86_64
--> Running transaction check
