引言：

      CentOS自带的yum源中rpm包数量有限，很多时候找不到我们需的软件包，（例如：要安装网络连接查看软件iftop，默认设置下无法使用yum命令安装），下面教大家在CentOS 6.2中（以32位系统为例，64位系统安装方法一样），使用第三方yum源来安装更多软件包。

一、安装CentOS yum源优先级插件yum-priorities      yum install yum-priorities   #输入y安装二、设置CentOS默认yum源的优先级为最高     cd  /etc/yum.repos.d/   #进入yum源目录     vi CentOS-Base.repo    #在[base]、[updates]、[extras]组下面添加priority=1，在[centosplus]、[contrib]组下面添加priority=2################################################################   [base]name=CentOS-$releasever - Basemirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/gpgcheck=1gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6priority=1

[updates]

name=CentOS-$releasever - Updatesmirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/gpgcheck=1gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6priority=1

[extras]

name=CentOS-$releasever - Extrasmirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/gpgcheck=1gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6priority=1

[centosplus]

name=CentOS-$releasever - Plusmirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/gpgcheck=1enabled=0gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6priority=2

[contrib]

name=CentOS-$releasever - Contribmirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib#baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/gpgcheck=1enabled=0gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6priority=2###############################################################   备注：priority的优先级为1到99，设置为1即优先级最高，1-10为系统保留，第三方yum源的优先级从11-99三、安装epel yum源    rpm -ivh      rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6    vi /etc/yum.repos.d/epel.repo   #修改epel yum源优先级，priority=11   ###############################################################    [epel]name=Extra Packages for Enterprise Linux 6 - $basearch#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearchmirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearchfailovermethod=priorityenabled=1gpgcheck=1gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6priority=11#################################################################四、安装rpmforge yum源   wget    wget    rpm --import RPM-GPG-KEY.dag.txt   rpm -ivh rpmforge-release-0.5.2-2.el6.rf.i686.rpm   vi  /etc/yum.repos.d/rpmforge.repo  #修改rpmforge yum源优先级，priority=12  #################################################################[rpmforge]name = RHEL $releasever - RPMforge.net - dagbaseurl = mirrorlist = #mirrorlist = file:///etc/yum.repos.d/mirrors-rpmforgeenabled = 1protect = 0gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-daggpgcheck = 1priority=12#################################################################

五、安装rpmfusion yum源   rpm -ivh    vi  /etc/yum.repos.d/rpmfusion-free-updates-testing.repo   #修改rpmfusion yum源优先级，priority=13 #################################################################[rpmfusion-free-updates-testing]name=RPM Fusion for EL 6 - Free - Test Updates#baseurl=http://download1.rpmfusion.org/free/el/updates/testing/6/$basearch/mirrorlist=http://mirrors.rpmfusion.org/mirrorlist?repo=free-el-updates-testing-6&arch=$basearchenabled=1gpgcheck=1gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-el-6priority=13#################################################################六、安装atomic yum源    wget   #下载    sh ./atomic   #安装    vi  /etc/yum.repos.d/atomic.repo  #修改atomic yum源优先级，priority=14##############################################################[atomic]name = CentOS / Red Hat Enterprise Linux $releasever - atomicrocketturtle.commirrorlist = #mirrorlist = enabled = 1priority = 1protect = 0gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY.art.txtgpgcheck = 1priority=14##############################################################七、更新yum软件包       yum check-update八、安装iftop       yum install iftop至此，CentOS 第三方yum源配置完成，现在你可以用yum命令安装自己需要的软件了！比如yum install nginx、yum update php等安装或者升级软件包。

备注：以下两个第三方yum源可以使用

rpm -Uvh  

rpm -Uvh 

yum --enablerepo=remi install php

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   扩展阅读：

   在使用yum update php命令升级php的同时，mysql也被升级到了最新版，升级好之后重启mysql，有可能会出现下面

   的错误信息，导致mysql启动失败。

   ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

   解决方法（切记，操作前，一定备份mysql数据库）：

   rm -fr /var/lib/mysql/*      #删除目录

   rm /var/lock/subsys/mysqld   #删除目录

   killall mysqld   #结束mysql进程

   service mysqld start  #启动mysql

   /etc/rc.d/init.d/mysqld status   #查看mysql状态

   mysql_secure_installation  #重置Mysql数据库密码

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