环境 vmware + centos5.7
目录 /data/Centos/i386/

1、挂载文件
mkdir -p /mnt/soft
mount -o loop -t iso9660 /dev/cdrom /mnt/soft
cd /data/Centos/i386/

2.新建一个自定义的目录，用来放置你的RPM包，并复制一份。
mkdir -p /data/Centos/i386/
cp -rf /mnt/soft/CentOS/ /data/CentOS/i386/
 
3.将/mnt/soft下的repodata/ 拷贝到/data/Centos/i386/CentOS下
cp -rf /mnt/soft/repodata/ /data/Centos/i386/CentOS/    
 
4.安装rpm -ivh /mnt/soft/CentOS/createrepo-0.4.11-3.el5.noarch.rpm  （此包是用来安装服务端设置软件仓库及信息文件）

5.生成客户端所需的信息文件
createrepo -g /mnt/soft/repodata/comps.xml /data/Centos/i386/
 
6.将key文件（用于客户端与服务端的认证）拷入指定目录/data/Centos/i386 下
cp /mnt/soft/RPM-GPG-KEY-CentOS-5 /data/Centos/i386/

7.更改yum的配置文件，更改之前CentOS-Base.repo要做好备份
vim CentOS-Base.repo
[base]
name=CentOS5.7-base
baseurl=file:///data/Centos/i386/
enable=1
gpgcheck=1
gpgkey=file:///data/Centos/i386/RPM-GPG-KEY-CentOS-5

先执行下yum clean all
 
验证结果
[root@lx_web_s1 CentOS]# yum install zlib
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package zlib.i386 0:1.2.3-4.el5 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================
 Package         Arch            Version                  Repository       Size
================================================================================
Updating:
 zlib            i386            1.2.3-4.el5              base             51 k

Transaction Summary
================================================================================
Install      0 Package(s)         
Update       1 Package(s)         
Remove       0 Package(s)        

Total download size: 51 k
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Updating       : zlib                                                     1/2 
  Cleanup        : zlib                                                     2/2

Updated:
  zlib.i386 0:1.2.3-4.el5                                                      

Complete!
这样安装/升级软件比网络源快很多。