說明：
操作系統：CentOS 6.x
IP地址：192.168.21.188
實現目的：同步CentOS鏡像站點的內容到此服務器，並且通過配置http服務器，能夠向外提供yum服務
準備篇：
一、安裝http服務器
這裏使用Nginx服務器提供http服務
關於Nginx服務器搭建，參考：CentOS安裝配置LNMP服務器（Nginx+PHP+MySQL）
http://www.osyunwei.com/archives/5910.html
二、系統約定
Nginx站點根目錄:/usr/local/nginx/html
服務器執行腳本文件存放目錄:/home/crontab
三、開始Nginx目錄瀏覽功能
vi /usr/local/nginx/conf/nginx.conf #編輯配置文件，在http {下面添加以下內容：
autoindex on; #開啓nginx目錄瀏覽功能
autoindex_exact_size off; #文件大小從KB開始顯示
autoindex_localtime on; #顯示文件修改時間爲服務器本地時間
:wq! #保存，退出
service nginx reload #重新加載配置
http://www.osyunwei.com/archives/5051.html
安裝篇：
一、創建鏡像文件存放目錄
mkdir -p /usr/local/nginx/html/centos #CentOS官方標準源
mkdir -p /usr/local/nginx/html/repoforge #第三方rpmforge源
mkdir -p /usr/local/nginx/html/epel #第三方epel源
說明：這裏創建三個文件夾，分別存放CentOS官方標準源、第三方的rpmforge源和epel源
二、確定以上三個yum源上游源的同步鏡像地址
1、CentOS官方標準源：rsync://mirrors.ustc.edu.cn/centos/
2、rpmforge源：rsync://mirrors.ispros.com.bd/repoforge/
3、epel源：rsync://mirrors.ustc.edu.cn/epel/
備註：上游yum源必須要支持rsync協議，否則不能使用rsync進行同步。
參考：
CentOS官方標準源：
rsync://mirrors.kernel.org/centos
rpmforge源：
http://apt.sw.be/
rsync://ftp-stud.fht-esslingen.de/dag
epel源：
http://mirrors.fedoraproject.org/publiclist/EPEL/
rsync://mirrors.kernel.org/fedora-epel
三、創建以上三個yum源同步腳本，並且設定腳本自動執行
mkdir -p /home/crontab #創建目錄
vi /home/crontab/yum_rsync.sh #添加以下代碼
#!/bin/sh
/usr/bin/rsync -avrt rsync://mirrors.ustc.edu.cn/centos/ --exclude-from=/usr/local/nginx/html/exclude_centos.list /usr/local/nginx/html/centos/
/usr/bin/rsync -avrt rsync://mirrors.ispros.com.bd/repoforge/ --exclude-from=/usr/local/nginx/html/exclude_repoforge.list /usr/local/nginx/html/repoforge/
/usr/bin/rsync -avrt rsync://mirrors.ustc.edu.cn/epel/ --exclude-from=/usr/local/nginx/html/exclude_epel.list /usr/local/nginx/html/epel/
:wq! #保存退出
chmod +x /home/crontab/yum_rsync.sh #添加腳本執行權限
備註：運行此腳本前，先要創建好同步目錄及不需要同步的目錄列表文件
cd /usr/local/nginx/html/ #進入目錄
touch exclude_centos.list #創建文件
touch exclude_repoforge.list #創建文件
touch exclude_epel.list #創建文件
把不需要同步的目錄寫到上面對應的文件中，每行一個目錄
例如：
vi exclude_epel.list
4/
4AS/
4ES/
4WS/
:wq! #保存退出
四、添加腳本定時執行任務
vi /etc/crontab #在最後一行添加以下代碼
0 1 * * * root /home/crontab/yum_rsync.sh #設置每天凌晨1點整開始執行腳本
:wq! #保存退出
service crond restart #重啓
測試篇：
一、安裝rsync同步軟件
yum install rsync xinetd #安裝
vi /etc/xinetd.d/rsync #編輯配置文件，設置開機啓動rsync
disable = no #修改爲
/etc/init.d/xinetd start #啓動（CentOS中是以xinetd 來管理Rsync服務的）
:wq! #保存退出
二、執行同步腳本
sh /home/crontab/yum_rsync.sh
注意：等待腳本執行完畢，首次同步，耗費的時間比較長！
三、根據不同版本創建三個yum源的repo配置文件
cd /etc/yum.repos.d/ #進入目錄
mv /etc/yum.repos.d/CentOS-Base.repo CentOS-Base.repo-bak
1、CentOS官方標準源：
CentOS 5.x系列：
vi /etc/yum.repos.d/CentOS-Base.repo #添加以下代碼
# 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-$releasever - Base - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-5
#released updates
[updates]
name=CentOS-$releasever - Updates - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-5
#packages used/produced in the build but not released
[addons]
name=CentOS-$releasever - Addons - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/addons/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=addons
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-5
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-5
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-5
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/contrib/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
gpgcheck=1
enabled=0
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-5
:wq! #保存退出
#########################
CentOS 6.x系列：
vi /etc/yum.repos.d/CentOS-Base.repo #添加以下代碼
# 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-$releasever - Base - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-$releasever - Updates - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/contrib/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
gpgcheck=1
enabled=0
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
:wq! #保存退出
#########################
CentOS 7.x系列：
vi /etc/yum.repos.d/CentOS-Base.repo #添加以下代碼
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#
[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://192.168.21.188/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-7
#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://192.168.21.188/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-7
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://192.168.21.188/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-7
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
baseurl=http://192.168.21.188/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-7
:wq! #保存退出
#########################
或者參考：https://lug.ustc.edu.cn/wiki/mirrors/help/centos
把裏面的http://mirrors.ustc.edu.cn/替換爲http://192.168.21.188/
2、rpmforge源：
CentOS 5.x系列：
vi /etc/yum.repos.d/rpmforge.repo #添加以下代碼
[rpmforge]
name = RHEL $releasever - RPMforge.net - dag
baseurl = http://192.168.21.188/repoforge/redhat/el5/en/$basearch/rpmforge
enabled = 1
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
[rpmforge-extras]
name = RHEL $releasever - RPMforge.net - extras
baseurl = http://192.168.21.188/repoforge/redhat/el5/en/$basearch/extras
enabled = 0
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
[rpmforge-testing]
name = RHEL $releasever - RPMforge.net - testing
baseurl = http://192.168.21.188/repoforge/redhat/el5/en/$basearch/testing
enabled = 0
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
:wq! #保存退出
#########################
CentOS 6.x系列：
vi /etc/yum.repos.d/rpmforge.repo #添加以下代碼
[rpmforge]
name = RHEL $releasever - RPMforge.net - dag
baseurl = http://192.168.21.188/repoforge/redhat/el6/en/$basearch/rpmforge
enabled = 1
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
[rpmforge-extras]
name = RHEL $releasever - RPMforge.net - extras
baseurl = http://192.168.21.188/repoforge/redhat/el6/en/$basearch/extras
enabled = 0
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
[rpmforge-testing]
name = RHEL $releasever - RPMforge.net - testing
baseurl = http://192.168.21.188/repoforge/redhat/el6/en/$basearch/testing
enabled = 0
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
:wq! #保存退出
#########################
CentOS 7.x系列：
vi /etc/yum.repos.d/rpmforge.repo #添加以下代碼
[rpmforge]
name = RHEL $releasever - RPMforge.net - dag
baseurl = http://192.168.21.188/repoforge/redhat/el7/en/$basearch/rpmforge
enabled = 1
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
[rpmforge-extras]
name = RHEL $releasever - RPMforge.net - extras
baseurl = http://192.168.21.188/repoforge/redhat/el7/en/$basearch/extras
enabled = 0
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
[rpmforge-testing]
name = RHEL $releasever - RPMforge.net - testing
baseurl = http://192.168.21.188/repoforge/redhat/el7/en/$basearch/testing
enabled = 0
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
:wq! #保存退出
#########################
3、epel源：
CentOS 5.x系列：
vi /etc/yum.repos.d/epel.repo #添加以下代碼
[epel]
name=Extra Packages for Enterprise Linux 5 - $basearch
baseurl=http://192.168.21.188/epel/5/$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-5
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 5 - $basearch - Debug
baseurl=http://192.168.21.188/epel/5/$basearch/debug
failovermethod=priority
enabled=0
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-5
gpgcheck=1
[epel-source]
name=Extra Packages for Enterprise Linux 5 - $basearch - Source
baseurl=http://192.168.21.188/epel/5/SRPMS
failovermethod=priority
enabled=0
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-5
gpgcheck=1
:wq! #保存退出
#########################
CentOS 6.x系列：
vi /etc/yum.repos.d/epel.repo #添加以下代碼
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://192.168.21.188/epel/6/$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-6
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://192.168.21.188/epel/6/$basearch/debug
failovermethod=priority
enabled=0
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-6
gpgcheck=1
[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://192.168.21.188/epel/6/SRPMS
failovermethod=priority
enabled=0
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-6
gpgcheck=1
:wq! #保存退出
#########################
CentOS 7.x系列：
vi /etc/yum.repos.d/epel.repo #添加以下代碼
[epel]
name=Extra Packages for Enterprise Linux 7 - $basearch
baseurl=http://192.168.21.188/epel/beta/7/$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-7
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 7 - $basearch - Debug
baseurl=http://192.168.21.188/epel/beta/7/$basearch/debug
failovermethod=priority
enabled=0
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-7
gpgcheck=1
[epel-source]
name=Extra Packages for Enterprise Linux 7 - $basearch - Source
baseurl=http://192.168.21.188/epel/beta/7/SRPMS
failovermethod=priority
enabled=0
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-7
gpgcheck=1
:wq! #保存退出
#########################
四、測試yum源是否配置正確
1、當前系統版本爲CentOS 6.x，以此爲例
cd /etc/yum.repos.d/
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
vi CentOS-Base.repo #添加以下代碼
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#
[base]
name=CentOS-$releasever - Base - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-$releasever - Updates - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - huanqiu.com
baseurl=http://192.168.21.188/centos/$releasever/contrib/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
gpgcheck=1
enabled=0
gpgkey=http://192.168.21.188/centos/RPM-GPG-KEY-CentOS-6
:wq! #保存退出
#########################
vi rpmforge.repo #添加以下代碼
[rpmforge]
name = RHEL $releasever - RPMforge.net - dag
baseurl = http://192.168.21.188/repoforge/redhat/el6/en/$basearch/rpmforge
enabled = 1
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
[rpmforge-extras]
name = RHEL $releasever - RPMforge.net - extras
baseurl = http://192.168.21.188/repoforge/redhat/el6/en/$basearch/extras
enabled = 0
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
[rpmforge-testing]
name = RHEL $releasever - RPMforge.net - testing
baseurl = http://192.168.21.188/repoforge/redhat/el6/en/$basearch/testing
enabled = 0
protect = 0
gpgkey=http://192.168.21.188/repoforge/RPM-GPG-KEY-rpmforge
gpgcheck = 1
:wq! #保存退出
#########################
vi epel.repo #添加以下代碼
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://192.168.21.188/epel/6/$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-6
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://192.168.21.188/epel/6/$basearch/debug
failovermethod=priority
enabled=0
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-6
gpgcheck=1
[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://192.168.21.188/epel/6/SRPMS
failovermethod=priority
enabled=0
gpgkey =http://192.168.21.188/epel/RPM-GPG-KEY-EPEL-6
gpgcheck=1
:wq! #保存退出
#########################
yum clean all #清除當前yum緩存
yum makecache #緩存yum源中的軟件包信息
yum repolist #列出yum源中可用的軟件包
2、使用yum命令安裝軟件
yum install php #測試CentOS官方標準源
yum install htop #測試rpmforge源
yum install nginx #測試epel源
至此，搭建CentOS在線yum源鏡像服務器完成！