CentOS是Linux的一個發行版。
特點：
＝＝＝
1、可以把CentOS理解爲Red Hat AS系列！它完全就是對Red Hat AS進行改進後發佈的！各種操作、使用和RED HAT沒有區別！
2、CentOS完全免費，不存在RED HAT AS4需要序列號的問題。
3、CentOS獨有的yum命令支持在線升級，可以即時更新系統，不像RED HAT那樣需要花錢購買支持服務！
4、CentOS修正了許多RED HAT AS的BUG！
一、使用更新源的國內鏡像
CentOS 安裝完畢，首先應該修改更新源，並升級到最新的系統。
國內速度較快的常用更新源：
http://mirror.be10.com/centos/
http://centos.candishosting.com.cn/
http://ftp.sjtu.edu.cn/centos/
http://ftp.hostrino.com/pub/centos/
http://mirrors.ta139.com/centos/
http://ftp.iasi.roedu.net/mirrors/centos.org/centos/
首先備份CentOS-Base.repo，然後再編輯 yum 的配置文件
[admingu@googe ~]$ sudo cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
[admingu@googe ~]$ sudo vi /etc/yum.repos.d/CentOS-Base.repo
[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
baseurl=http://centos.candishosting.com.cn/$releasever/os/$basearch/
http://mirrors.ta139.com/centos/$releasever/os/$basearch/
http://mirror.be10.com/centos/$releasever/os/$basearch/
http://ftp.sjtu.edu.cn/centos/$releasever/os/$basearch/
http://ftp.hostrino.com/pub/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
baseurl=http://centos.candishosting.com.cn/$releasever/updates/$basearch/
http://mirrors.ta139.com/centos/$releasever/updates/$basearch/
http://mirror.be10.com/centos/$releasever/updates/$basearch/
http://ftp.sjtu.edu.cn/centos/$releasever/updates/$basearch/
http://ftp.hostrino.com/pub/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
#packages used/produced in the build but not released
[addons]
name=CentOS-$releasever - Addons
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=addons
#baseurl=http://mirror.centos.org/centos/$releasever/addons/$basearch/
baseurl=http://centos.candishosting.com.cn/$releasever/addons/$basearch/
http://mirrors.ta139.com/centos/$releasever/addons/$basearch/
http://mirror.be10.com/centos/$releasever/addons/$basearch/
http://ftp.sjtu.edu.cn/centos/$releasever/addons/$basearch/
http://ftp.hostrino.com/pub/centos/$releasever/addons/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
baseurl=http://centos.candishosting.com.cn/$releasever/extras/$basearch/
http://mirrors.ta139.com/centos/$releasever/extras/$basearch/
http://mirror.be10.com/centos/$releasever/extras/$basearch/
http://ftp.sjtu.edu.cn/centos/$releasever/extras/$basearch/
http://ftp.hostrino.com/pub/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
baseurl=http://centos.candishosting.com.cn/$releasever/centosplus/$basearch/
http://mirrors.ta139.com/centos/$releasever/centosplus/$basearch/
http://mirror.be10.com/centos/$releasever/centosplus/$basearch/
http://ftp.sjtu.edu.cn/centos/$releasever/centosplus/$basearch/
http://ftp.hostrino.com/pub/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
#baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/
baseurl=http://centos.candishosting.com.cn/$releasever/contrib/$basearch/
http://mirrors.ta139.com/centos/$releasever/contrib/$basearch/
http://mirror.be10.com/centos/$releasever/contrib/$basearch/
http://ftp.sjtu.edu.cn/centos/$releasever/contrib/$basearch/
http://ftp.hostrino.com/pub/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
其中：
repositoryid:用於指定一個倉庫
name：用於指定易讀的倉庫名稱
baseurl：用於指定本倉庫的URL，可以是以下的3種類型，如http,ftp,file
mirrorlist：用於指定倉庫的鏡像站點
enable：用於指定是否使用本倉庫，默認值爲1，即可用。
gpgcheck：用於指定是否檢查軟件包的GPG簽名。
gpgkey：用於指定GPG簽名文件的URL。
執行命令：
[admingu@googe ~]$ sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY*
二、使用非官方更新源
下面以安裝rpmforge和DAG軟件包爲例添加非官方更新源
I、添加rmpforge軟件庫
1）到http://dag.wieers.com/rpm/packages/rpmforge-release/查找適用於RHEL5/CentOS5的軟件包。
2）下載適用於RHEL5/CentOS5的軟件包。
[admingu@googe ~]$ sudo wget http://dag.wieers.com/rpm/packag ... 6-1.el5.rf.i386.rpm
[admingu@googe ~]$ sudo rpm -ivh rpmforge-release-0.3.6-1.el5.rf.i386.rpm
[admingu@googe ~]$ sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-*
安裝rpmforge-release軟件包之後，就可以看到/etc/yum.repos.d/rpmforge.repo文件，以後yum就可以使用這個更新源了。
II、添加DAG更新倉庫。
1)在/etc/yum.repos.d/下建立dag.repo
2)編輯dag.repo
[admingu@googe ~]$ sudo vi /etc/yum.repos.d/dag.repo
[dag]
name=Dag RPM Repository for Red Hat Enterprise Linux
baseurl=http://apt.sw.be/redhat/el5/en/i386/dag
gpgcheck=1
enabled=1
gpgkey=http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt
保存退出。
然後導入Key,
[admingu@googe ~]$ sudo rpm --import http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt
添加DAG可能會有點問題，這要看所在網速如何？
三、使用如下命令更新到最新系統
# yum upgrade
四、安裝必要的軟件工具
# yum install wget bzip2 unzip zip nmap tree lynx fileutils ncftp lftp
若您需要在本機編譯源代碼的軟件，請安裝開發工具組的軟件包
# yum groupinstall "Development Tools"
二 RHEL5建立自己的源
爲了解決軟件包的依賴問題，紅帽系列發行版最好的方式是利用yum，但用紅帽子的yum源安裝軟件有諸多限制，棄之，還有兩種方法，一個是用centos 對應版本的yum源，不過centos一般都是慢rhel半拍纔出來，第二是自己用rhel安裝光盤文件裏的文件構建yum源，這裏以http方式（還可以本地光盤方式，本地文件方式），本文記錄簡要過程，僅供參考。
1.掛載安裝光盤到系統
- mount /dev/cdrom /media/
複製代碼
2.複製文件到web服務器rhel5目錄下
- cp -fr /media/* /var/www/htm/rhel5
複製代碼
3.重建記錄分組文件
首先，確認系統已經安裝createrepo包。
- cd /var/www/htm/rhel5/Server
- rpm -ivh createrepo-0.4.11-3.el5.noarch.rpm
複製代碼
然後重建rpm記錄分組文件
- createrepo -g /var/www/html/rhel5/VT/repodata/comps-rhel5-vt.xml /var/www/html/rhel5/VT
- createrepo -g /var/www/html/rhel5/Cluster/repodata/comps-rhel5-cluster.xml /var/www/html/rhel5/Cluster
- createrepo -g /var/www/html/rhel5/ClusterStorage/repodata/comps-rhel5-cluster-st.xml /var/www/html/rhel5/ClusterStorage
- createrepo -g /var/www/html/rhel5/Server/repodata/comps-rhel5-server-core.xml /var/www/html/rhel5/Server
複製代碼
4.在/etc/yum.repos.d目錄下建立repo庫文件 rhel5-http.repo
(注：此文件名任意，文件後綴名必須是repo)
cd /etc/yum.repos.d
vi rhel5-http.repo
#我的機器IP是爲192.168.171.3
[Cluster]
name=Red Hat Enterprise Linux $releasever - $basearch - Cluster
baseurl=http://192.168.171.3/rhel5/Cluster
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
[ClusterStorage]
name=Red Hat Enterprise Linux $releasever - $basearch - ClusterStorage
baseurl=http://192.168.171.3/rhel5/ClusterStorage
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
[Server]
name=Red Hat Enterprise Linux $releasever - $basearch - Server
baseurl=http://192.168.171.3/rhel5/Server
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
[VT]
name=Red Hat Enterprise Linux $releasever - $basearch - VT
baseurl=http://192.168.171.3/rhel5/VT
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
5.清除本機yum緩存
yum clean all
6.測試
yum -y install vim*
引用
Loaded plugins: rhnplugin, security
This system is not registered with RHN.
RHN support will be disabled.
Setting up Install Process
Parsing package install arguments
Package 2:vim-minimal-7.0.109-4.el5_2.4z.i386 already installed and latest version
Package 2:vim-common-7.0.109-4.el5_2.4z.i386 already installed and latest version
Package 2:vim-enhanced-7.0.109-4.el5_2.4z.i386 already installed and latest version
Resolving Dependencies
--> Running transaction check
---> Package vim-X11.i386 2:7.0.109-4.el5_2.4z set to be updated
--> Finished Dependency Resolution
Dependencies Resolved
=============================================================================================================================
Package Arch Version Repository Size
=============================================================================================================================
Installing:
vim-X11 i386 2:7.0.109-4.el5_2.4z Server 1.4 M
Transaction Summary
=============================================================================================================================
Install 1 Package(s)
Update 0 Package(s)
Remove 0 Package(s)
Total download size: 1.4 M
Downloading Packages:
vim-X11-7.0.109-4.el5_2.4z.i386.rpm | 1.4 MB 00:00
warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID 37017186
Importing GPG key 0x37017186 "Red Hat, Inc. (release key) " from /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : vim-X11 [1/1]
Installed: vim-X11.i386 2:7.0.109-4.el5_2.4z
Complete!
7.分發rhel5-http.repo到其他機器以供使用。