RHEL7 默认是最小化安装（Minimal Install），没有图形界面，
我们应该选择Server with GUI。若已错过此步骤，我们采用以下方式补充安装GUI界面。

先配置yum源

[root@LiuZhen mnt]# rpm --import RPM-GPG-KEY-redhat-release

执行以下命令

[root@LiuZhen mnt]# yum group list

Loaded plugins: langpacks, product-id, subscription-manager

This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.

There is no installed groups file.

Maybe run: yum groups mark convert (see man yum)

Available environment groups:

   Minimal Install

   Infrastructure Server

   File and Print Server

   Basic Web Server

   Virtualization Host

   Server with GUI

Available Groups:

   Compatibility Libraries

   Console Internet Tools

   Development Tools

   Graphical Administration Tools

   Legacy UNIX Compatibility

   Scientific Support

   Security Tools

   Smart Card Support

   System Administration Tools

   System Management

Done

[root@LiuZhen mnt]#

 列出的组包中 Server with GUI 就是安装图形所需要的，继续执行以下命令

[root@LiuZhen mnt]# yum -y groupinstall "Server with GUI"

Loaded plugins: langpacks, product-id, subscription-manager

This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.

There is no installed groups file.

Maybe run: yum groups mark convert (see man yum)

Package 1:NetworkManager-config-server-0.9.9.1-12.git20140326.4dba720.el7.x86_64 already installed and latest version

Warning: Group core does not have any packages to install.

Warning: Group gnome-desktop does not have any packages to install.

Warning: Group guest-agents does not have any packages to install.

Package gtk2-immodule-xim-2.24.22-5.el7.x86_64 already installed and latest version

Package imsettings-gsettings-1.6.3-9.el7.x86_64 already installed and latest version

Package ibus-gtk3-1.5.3-11.el7.x86_64 already installed and latest version

Package ibus-gtk2-1.5.3-11.el7.x86_64 already installed and latest version

Package gtk3-immodule-xim-3.8.8-5.el7.x86_64 already installed and latest version

Warning: Group input-methods does not have any packages to install.

Group input-methods does have 2 conditional packages, which may get installed.

Warning: Group guest-desktop-agents does not have any packages to install.

Warning: Group fonts does not have any packages to install.

Warning: Group print-client does not have any packages to install.

Warning: Group desktop-debugging does not have any packages to install.

Warning: Group dial-up does not have any packages to install.

Warning: Group base does not have any packages to install.

Group base does have 1 conditional packages, which may get installed.

Package gstreamer1-plugins-bad-free-1.0.7-4.el7.x86_64 already installed and latest version

Package gstreamer1-plugins-good-1.0.7-5.el7.x86_64 already installed and latest version

Warning: Group multimedia does not have any packages to install.

Warning: Group internet-browser does not have any packages to install.

Warning: Group x11 does not have any packages to install.

Maybe run: yum groups mark install (see man yum)

No packages in any requested group available to install or update

[root@LiuZhen mnt]# show-installed

WARNING: The following packages are installed but not in the repository:

cups-pdf

WARNING: The following groups contain packages not found in the repositories:

XXX base

yum-plugin-security

XXX core

ql2100-firmware

ql23xx-firmware

ql2200-firmware

bfa-firmware

XXX gnome-desktop

unoconv

polkit-gnome

gvfs-obexftp

@base

-yum-plugin-security

@core

-bfa-firmware

-ql2100-firmware

-ql2200-firmware

-ql23xx-firmware

@dial-up

@fonts

@gnome-desktop

-gvfs-obexftp

-polkit-gnome

-unoconv

@guest-agents

@guest-desktop-agents

@input-methods

@internet-browser

@multimedia

@print-client

@x11

# Others

Red_Hat_Enterprise_Linux-Release_Notes-7-zh-CN

Red_Hat_Enterprise_Linux-Release_Notes-7-zh-TW

clucene-core

cups-pdf

grub2

lftp

samba-client

screen

# 1196 package names, 228 leaves

# 12 groups, 8 leftovers, 8 excludes

# 32 lines

可以执行startx看下效果。