YUM是一种安装软件包的工具，这个工具可以自行解决rpm软件包之间的依赖关系，可以实现快速安装软件包。

（1）、挂载光驱，将光盘 ISO文件挂载到目录 /mnt/sr0
            [root@localhost /]# mkdir /mnt/sr0
            [root@localhost /]# mount /dev/sr0 /mnt/sr0/
            mount: block device /dev/sr0 is write-protected, mounting read-only
 
            创建本地目录，用来copy光盘包。
            [root@localhost ~]# mkdir -p /CentOS/local_repo

            copy RPM 包到指定目录。
            [root@localhost media]# cd /mnt/sr0/Packages/
            [root@localhost Packages]# cp *  /CentOS/local_repo/

            安装 createrepo 包，该软件用来解析依赖关系。
            [root@localhost Packages]# rpm -ivh deltarpm-3.5-0.5.20090913git.el6.x86_64.rpm
             Preparing...                ########################################### [100%]
               1:deltarpm               ########################################### [100%]
            [root@localhost Packages]# rpm -ivh python-deltarpm-3.5-0.5.20090913git.el6.x86_64.rpm
             Preparing...                ########################################### [100%]
              1:python-deltarpm        ########################################### [100%]
            [root@localhost Packages]# rpm -ivh createrepo-0.9.9-18.el6.noarch.rpm
             Preparing...                ########################################### [100%]
              1:createrepo             ########################################### [100%]
            
             创建 repo 数据库。
             [root@localhost Packages]# createrepo -d /CentOS/local_repo/

             进入yum.repos.d 目录下会有4个文件，编辑CentOS-Media.repo这个文件。编辑后将CentOS-
            Base.repo该名，下面是在源文件后面加个后缀.BAK。如果不将此文件改名或移除系统将默认通过
             该文件找YUM源。

             [root@localhost ~]# cd /etc/yum.repos.d/
             [root@localhost yum.repos.d]# ll
             总用量 16
             -rw-r--r--. 1 root root 1926 11月 27 2013 CentOS-Base.repo.BAK
             -rw-r--r--. 1 root root  638 11月 27 2013 CentOS-Debuginfo.repo
             -rw-r--r--. 1 root root  581 5月  25 21:59 CentOS-Media.repo
             -rw-r--r--. 1 root root 3664 11月 27 2013 CentOS-Vault.repo

             [root@localhost yum.repos.d]# vim CentOS-Media.repo
              # CentOS-Media.repo
              #  This repo can be used with mounted DVD media, verify the mount point for
              #  CentOS-6.  You can use this repo and yum to install items directly off the
              #  DVD ISO that we release.
             #
             # To use this repo, put in your DVD and use it with the other repos too:
            #  yum --enablerepo=c6-media [command]
            #
           # or for ONLY the media repo, do this:
           #
           #  yum --disablerepo=\* --enablerepo=c6-media [command]

           [c6-media]
            name=CentOS-$releasever - Media
            baseurl=file:///CentOS/local_repo/

           gpgcheck=1
           enabled=1
           gpgkey=file:///mnt/src/RPM-GPG-KEY-CentOS-6

          测试仓库
          [root@localhost ~]# yum clean all
          Loaded plugins: fastestmirror, security
         Cleaning repos: c6-media
         Cleaning up Everything
         Cleaning up list of fastest mirrors
         [root@localhost ~]# yum repolist
         Loaded plugins: fastestmirror, security
         Determining fastest mirrors
         c6-media                                                                | 2.9 kB     00:00 ...
        c6-media/primary_db                                                     | 3.3 MB     00:00 ...
        repo id                                 repo name                                        status
        c6-media                                CentOS-6 - Media                                 3,995
        repolist: 3,995
        [root@localhost ~]#