RedHat7.0更新yum源（踩过的坑）
前言
redhat系统安装好尽管默认带有yum，但是redhat的更新包只对注册用户有效，对于我们这些穷人来说，只有自己手动更改成CentOS的更新包了。
最初在网上查找资料：Redhat 7使用CentOS 7的Yum网络源
基本的流程就是：
- 删除redhat7.0系统自带的yum软件包；
- 自行下载所需要的软件包；
- 根据依赖项安装；
- 新建repo配置文件。
一般来说，之后就可以正常使用了。可能还会遇到一些依赖项的问题，后面会提到。
流程
1、查看自带的yum软件包
[root@xhb yum.repos.d]# 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这下面列出来的软件包，要记住一下，后面要根据其来搜索rpm包来安装新版本。比如”yum-utils”、”yum-langpacks”等等。
2、卸载这些安装包
rpm -qa | grep yum | xargs rpm -e --nodeps3、保证上网正常
ping www.baidu.com4、进入以下网站下载对应的rpm包
阿里云网络源地址：https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/
网易163网络源地址：http://mirrors.163.com/
CentOS网络源地址：http://centos.ustc.edu.cn/centos/
使用CTRL+F输入关键字查找对应的安装包即可。
5、找到安装包后下载下来
由于输出结果较多，故省略，下面是指令：
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-154.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-1.1.31-42.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-updateonboot-1.1.31-42.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-utils-1.1.31-42.el7.noarch.rpm6、安装
输入指令rpm -ivh yum-*，遇到报错，依赖项问题。
[root@xhb Packages]# rpm -ivh yum-*
warning: yum-3.4.3-154.el7.centos.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
error: Failed dependencies:
rpm >= 0:4.11.3-22 is needed by yum-3.4.3-154.el7.centos.noarch另外再回去找安装包下载下来：
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-25.el7.x86_64.rpm输入指令更新rpm：
rpm -Uvh rpm-4.11.3-25.el7.x86_64.rpm --nodeps再次运行rpm -ivh yum-*，可以正常安装了。
[root@xhb Packages]# rpm -ivh yum-*
warning: yum-3.4.3-154.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-1.1.31-4################################# [ 40%]
3:yum-3.4.3-154.el7.centos ################################# [ 60%]
4:yum-updateonboot-1.1.31-42.el7 ################################# [ 80%]
5:yum-utils-1.1.31-42.el7 ################################# [100%]
7、新建repo配置文件
创建repo文件：
vim /etc/yum.repos.d/CentOS-Base.repo输入以下内容：
#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-$7 - Base - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=$7&arch=$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=$7&arch=$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=$7&arch=$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-78、测试yum是否配置成功
随便下一个软件看看：
[root@xhb yum.repos.d]# yum -y install tree
Loaded plugins: fastestmirror, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
base | 3.6 kB 00:00
extras | 3.4 kB 00:00
updates | 3.4 kB 00:00
(1/4): base/x86_64/group_gz | 156 kB 00:00
(2/4): extras/x86_64/primary_db | 166 kB 00:00
(3/4): base/x86_64/primary_db | 5.7 MB 00:02
(4/4): updates/x86_64/primary_db | 6.0 MB 00:02
Determining fastest mirrors
Resolving Dependencies
--> Running transaction check
---> Package tree.x86_64 0:1.6.0-10.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
tree x86_64 1.6.0-10.el7 base 46 k
Transaction Summary
================================================================================
Install 1 Package
Total download size: 46 k
Installed size: 87 k
Downloading packages:
warning: /var/cache/yum/x86_64/$releasever/base/packages/tree-1.6.0-10.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
Public key for tree-1.6.0-10.el7.x86_64.rpm is not installed
tree-1.6.0-10.el7.x86_64.rpm | 46 kB 00:00
Retrieving key from http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
Importing GPG key 0xF4A80EB5:
Userid : "CentOS-7 Key (CentOS 7 Official Signing Key) "
Fingerprint: 6341 ab27 53d7 8a78 a7c2 7bb1 24c6 a8a7 f4a8 0eb5
From : http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Warning: RPMDB altered outside of yum.
** Found 4 pre-existing rpmdb problem(s), 'yum check' output follows:
PackageKit-0.8.9-11.el7.x86_64 has missing requires of PackageKit-backend
rhn-check-2.0.2-5.el7.noarch has missing requires of yum-rhn-plugin >= ('0', '1.6.4', '1')
rpm-libs-4.11.1-16.el7.x86_64 has missing requires of rpm = ('0', '4.11.1', '16.el7')
rpm-python-4.11.1-16.el7.x86_64 has missing requires of rpm = ('0', '4.11.1', '16.el7')
Installing : tree-1.6.0-10.el7.x86_64 1/1
Verifying : tree-1.6.0-10.el7.x86_64 1/1
Installed:
tree.x86_64 0:1.6.0-10.el7
Complete!