XManager5連接CentOS6的方法已經行不通了，那么如何用XManager5連接CentOS7
從Xmanger官網博客得知：
“Gnome in CentOS 7 tries to use local hardware acceleration and this becomes a problem when trying to connect remotely using XDMCP. To avoid this problem, you have to use an alternative display manager (other than ‘gdm’) and desktop environment.”
“This guide explains how you can change the display manager to lightdm from gdm and desktop environment from Gnome to Xfce.”
這就是使用Xfce而不用gdm的原因（僅限CentOS7），嗯，不懂的可以百度一下。
參考：
http://blog.netsarang.com/89/connecting-to-centos-7/
http://blog.csdn.net/lic95/article/details/48948099
http://blog.csdn.net/wuzhimang/article/details/51523867
1.安裝源
# yum install epel-release -y
2.安裝lightdm
# yum install lightdm -y
3.編寫配置文件
# vi /etc/lightdm/lightdm.conf
[XDMCPServer]
enabled=true
port=177
4.設置默認顯示為lightdm
# systemctl disable gdm ; systemctl enable lightdm
5.啟動lightdm
#systemctl start lightdm
6.安裝xfce桌面，
#yum groupinstall -y xfce
7.刪除gnome文件
關鍵的一步，刪除gnome文件，不然啟動的時候還是gnome而不是xfce
# cd /usr/share/xsessions/
# mkdir bak
# mv gnome* bak
# systemctl restart lightdm
8.將Display Manager切換為lightdm
#systemctl disable gdm && systemctl enable lightdm
9.啟動lightdm
#systemctl start lightdm
10.關閉防火牆
#systemctl stop firewalld.service
11、查看可用的中文安裝包
# yum list kde*chinese
12、安裝中文包
# yum install kde-l10n-Chinese.noarch
13、修改開啟啟動模式
[root@k8smaster /]# vi /etc/inittab
# multi-user.target: analogous to runlevel 3
graphical.target: analogous to runlevel 5
上面multi-user.target是命令行模式
上面graphical.target圖形界面模式
14、設置啟動模式
[root@k8smaster /]# systemctl set-default graphical.target