首先用VMware12虚拟机，光驱载入redhat7安装光盘iso文件。
创建挂载点
[root@localhost ~]#mkdir /mnt/cdrom
[root@localhost ~]# mount -lv /dev/sr0 /mnt/cdrom
mount: /dev/sr0 is write-protected, mounting read-only
mount: /dev/sr0 mounted on /mnt/cdrom.
[root@localhost ~]# ls /mnt/cdrom
addons images Packages RPM-GPG-KEY- redhat-release
EFI isolinux release-notes TRANS.TBL
EULA LiveOS repodata
GPL media.repo RPM-GPG-KEY-redhat-beta
编辑yum配置文件
[root@localhost ~]# vim /etc/yum.repos.d/rhcsa.repo
[rhcsa]
name=rhcsa
baseurl=file:///mnt/cdrom
enable=1
gpgcheck=0
保存退出，然后yum clean all, yum makecache 就OK了
[root@localhost ~]# yum clean all
Loaded plugins: fastestmirror, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Cleaning repos: base extras rhcsa updates
Cleaning up everything
Maybe you want: rm -rf /var/cache/yum, to also free up space taken by orphaned data from disabled or removed repos
Cleaning up list of fastest mirrors
[root@localhost ~]# yum makecache
Loaded plugins: fastestmirror, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
base | 3.6 kB 00:00
extras | 3.4 kB 00:00
rhcsa | 4.1 kB 00:00
updates | 3.4 kB 00:00
(1/17): base/x86_64/group_gz | 166 kB 00:05
(2/17): base/x86_64/filelists_db | 6.9 MB 00:10
(3/17): base/x86_64/other_db | 2.5 MB 00:02
(4/17): base/x86_64/primary_db | 5.9 MB 00:08
(5/17): extras/x86_64/filelists_db | 603 kB 00:04
(6/17): extras/x86_64/prestodelta | 100 kB 00:04
(7/17): extras/x86_64/primary_db | 204 kB 00:00
(8/17): rhcsa/group_gz | 134 kB 00:00
(9/17): rhcsa/filelists_db | 3.0 MB 00:00
(10/17): rhcsa/other_db | 1.3 MB 00:00
(11/17): rhcsa/primary_db | 3.4 MB 00:00
(12/17): rhcsa/productid | 1.6 kB 00:00
(13/17): extras/x86_64/other_db | 126 kB 00:02
(14/17): updates/x86_64/prestodelta | 675 kB 00:05
(15/17): updates/x86_64/filelists_db | 3.4 MB 00:06
(16/17): updates/x86_64/other_db | 576 kB 00:00
(17/17): updates/x86_64/primary_db | 6.0 MB 00:46
Determining fastest mirrors
Metadata Cache Created
最后写入/etc/fstab 开机启动，增加一句
/dev/sr0 /mnt/cdrom iso9660 defaults 0 0
或者直接
echo "/dev/sr0 /mnt/cdrom iso9660 defaults 0 0" >> /etc/fstab
