Centos6.0使用第三方YUM源（EPEL，RPMForge，RPMFusion）
yum是centos下很方便的rpm包管理工具，配置第三方软件库使你的软件库更加丰富。以下简单的讲下配置的步骤。
首先，需要安装yum-priorities插件：
yum install yum-priorities -y
该插件的作用主要是设置调用源时的优先级的，一般将官方的优先级设置为最高。例如：
[base]
name=CentOS-$releasever - Base
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
priority=1
在每个[]段的最后加上priority=[]字段来设置每个镜像的优先级，1为最高，99为最低。
一般的配置为:
[base], [addons], [updates], [extras] … priority=1
[CentOSplus],[contrib] … priority=2
其他第三的软件源为：priority=N （推荐N>10）
###安装epel.repo，下载地址为 http://download.fedora.redhat.com/pub/epel/ 找与自己系统版本相符的包
rpm -ivh http://download.fedora.redhat.com/pub/epel/6/x86_64/epel-release-6-5.noarch.rpm
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
修改epel.repo，
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
priority=11
设置epel.repo的优先级为11.
###安装rpmforge.repo，下载地址为 http://pkgs.repoforge.org/rpmforge-release/ 找与自己系统版本相符的包
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
wget http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt
rpm -import RPM-GPG-KEY.dag.txt
rpm -K rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
rpm -ivh rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
修改rpmforge.repo，
[rpmforge]
name = RHEL $releasever - RPMforge.net - dag
baseurl = http://apt.sw.be/redhat/el6/en/$basearch/rpmforge
mirrorlist = http://apt.sw.be/redhat/el6/en/mirrors-rpmforge
#mirrorlist = file:///etc/yum.repos.d/mirrors-rpmforge
enabled = 1
protect = 0
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-dag
gpgcheck = 1
priority=12
设置rpmforge.repo优先级为12
###安装rpmfusion.repo,下载地址为http://download1.rpmfusion.org
rpm -ivh http://download1.rpmfusion.org/free/el/updates/testing/6/x86_64/rpmfusion-free-release-6-0.1.noarch.rpm
rpm -ivh http://download1.rpmfusion.org/nonfree/el/updates/testing/6/x86_64/rpmfusion-nonfree-release-6-0.1.noarch.rpm
修改rpmfusion.repo，
[rpmfusion-nonfree-updates-testing]
name=RPM Fusion for EL 6 - Nonfree - Test Updates
#baseurl=http://download1.rpmfusion.org/nonfree/el/updates/testing/6/$basearch/
mirrorlist=http://mirrors.rpmfusion.org/mirrorlist?repo=nonfree-el-updates-testing-6&arch=$basearch
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-nonfree-el-6
priority=13
设置优先级为13
测试：
yum check-update
会载入yum-priorities插件
yum install nginx -y
成功安装
参考文档：http://wiki.centos.org/zh/AdditionalResources/Repositories/RPMForge