Redhat AS4和AS5升级至Centos系统!

单位很多服务器都是Redhat AS4和AS5的机器，平时经常需要安装和编译软件包，到Centos能够方便不少!

网上查阅了相关资料，但是都不尽如人意，最终自己摸索出以下方法，和大家一起分享!

查看当前系统版本号# less /etc/redhat-release 检查系统已安装的组件包中是否已存在Redhat的自带的yum系列组件包# su root# rpm -qa | grep yum 如果存在请逐一全部删除# rpm -e --nodeps 组件包名称 建立Centos专用目录，然后下载并安装Centos系统的yum系列组件包# su webuser# cd /home/webuser# mkdir centos 下载Centos升级组件包（注：根据RedHat AS4或RedHat AS5分别操作） RedHat AS4： # wget http://centos.ustc.edu.cn/centos/4.7/os/i386/CentOS/RPMS/python-elementtree-1.2.6-5.el4.centos.i386.rpm# wget http://centos.ustc.edu.cn/centos/4.7/os/i386/CentOS/RPMS/python-sqlite-1.1.7-1.2.1.i386.rpm# wget http://centos.ustc.edu.cn/centos/4.7/os/i386/CentOS/RPMS/python-urlgrabber-2.9.8-2.noarch.rpm# wget http://centos.ustc.edu.cn/centos/4.7/os/i386/CentOS/RPMS/sqlite-3.3.6-2.i386.rpm# wget http://centos.ustc.edu.cn/centos/4.7/os/i386/CentOS/RPMS/yum-2.4.3-4.el4.centos.noarch.rpm# wget http://centos.ustc.edu.cn/centos/4.7/os/i386/CentOS/RPMS/yum-metadata-parser-1.0-8.el4.centos.i386.rpm# wget http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-4 RedHat AS5： # wget http://centos.ustc.edu.cn/centos/5.3/os/i386/CentOS/python-iniparse-0.2.3-4.el5.noarch.rpm# wget http://centos.ustc.edu.cn/centos/5.3/os/i386/CentOS/yum-3.2.19-18.el5.centos.noarch.rpm# wget http://centos.ustc.edu.cn/centos/5.3/os/i386/CentOS/yum-fastestmirror-1.1.16-13.el5.centos.noarch.rpm# wget http://centos.ustc.edu.cn/centos/5.3/os/i386/CentOS/yum-metadata-parser-1.1.2-2.el5.i386.rpm# wget http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5 安装Centos升级组件包# su root# rpm -Uvh --nodeps /home/webuser/centos/*.rpm 导入Centos升级组件授权（注：根据RedHat AS4或RedHat AS5分别操作） RedHat AS4：# rpm --import /home/webuser/centos/RPM-GPG-KEY-CentOS-4 RedHat AS5：# rpm --import /home/webuser/centos/RPM-GPG-KEY-CentOS-5 创建并编辑yum升级源配置文件# su root# mkdir -p /etc/yum.repos.d/# vi /etc/yum.repos.d/CentOS-Base.repo粘贴以下内容覆盖文件： RedHat AS4： [base]name=CentOS-$releasever - Basebaseurl=http://centos.ustc.edu.cn/centos/4.7/os/$basearch/gpgcheck=1gpgkey= http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-4 #released updates[update]name=CentOS-$releasever - Updatesbaseurl=http://centos.ustc.edu.cn/centos/4.7/updates/$basearch/gpgcheck=1gpgkey= http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-4 #packages used/produced in the build but not released[addons]name=CentOS-$releasever - Addonsbaseurl=http://centos.ustc.edu.cn/centos/4.7/addons/$basearch/gpgcheck=1gpgkey= http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-4 #additional packages that may be useful[extras]name=CentOS-$releasever - Extrasbaseurl=http://centos.ustc.edu.cn/centos/4.7/extras/$basearch/gpgcheck=1gpgkey= http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-4 #additional packages that extend functionality of existing packages[centosplus]name=CentOS-$releasever - Plusbaseurl=http://centos.ustc.edu.cn/centos/4.7/centosplus/$basearch/gpgcheck=1enabled=0gpgkey= http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-4 #contrib - packages by Centos Users[contrib]name=CentOS-$releasever - Contribbaseurl=http://centos.ustc.edu.cn/centos/4.7/contrib/$basearch/gpgcheck=1enabled=0gpgkey= http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-4 RedHat AS5： [base]name=CentOS-$releasever - Basebaseurl=http://centos.ustc.edu.cn/centos/5.3/os/$basearch/gpgcheck=1gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5 #released updates[update]name=CentOS-$releasever - Updatesbaseurl=http://centos.ustc.edu.cn/centos/5.3/updates/$basearch/gpgcheck=1gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5 #packages used/produced in the build but not released[addons]name=CentOS-$releasever - Addonsbaseurl=http://centos.ustc.edu.cn/centos/5.3/addons/$basearch/gpgcheck=1gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5 #additional packages that may be useful[extras]name=CentOS-$releasever - Extrasbaseurl=http://centos.ustc.edu.cn/centos/5.3/extras/$basearch/gpgcheck=1gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5 #additional packages that extend functionality of existing packages[centosplus]name=CentOS-$releasever - Plusbaseurl=http://centos.ustc.edu.cn/centos/5.3/centosplus/$basearch/gpgcheck=1enabled=0gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5 #contrib - packages by Centos Users[contrib]name=CentOS-$releasever - Contribbaseurl=http://centos.ustc.edu.cn/centos/5.3/contrib/$basearch/gpgcheck=1enabled=0gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5 核对后保存并退出 开始升级系统# yum update等待系统列出需要升级的组件清单并按”y”确认Total download size: 334 MIs this ok [y/n]: y…Complete!等待全部组件下载完成后，重新启动服务器，操作系统升级完毕！