# 安装epel源
[root@webapp128 ~]# mount -o loop rhel-server-7.2-x86_64-dvd.iso /mnt/redhat7.2
#安装lightdm和Xfce
[root@webapp128 ~]# yum install -y lightdm
[root@webapp128 ~]# yum groupinstall -y xfce
# 修改lightdm.conf文件(配置文件中有详细的参数说明)
[root@webapp128 ~]# vim /etc/lightdm/lightdm.conf
[XDMCPServer]
enabled=true
port=177...
# 将Display Manager切换为lightdm
[root@webapp128 ~]# systemctl disable gdm && systemctl enable lightdm
# 启动lightdm
[root@webapp128 ~]# systemctl start lightdm
# 关闭或者取消防火墙(若已关闭则忽略)
[root@webapp128 ~]# systemctl stop firewalld.service
# 只保留/usr/share/xsessions/下xfce.desktop文件
[root@webapp128 ~]# cd /usr/share/xsessions/ && ls gnome-classic.desktop gnome-custom-session.desktop gnome.desktop xfce.desktop
[root@webapp128 ~]# mkdir back && mv gnome* back && ls back xfce.desktop
#启动lightdm
[root@webapp128 ~]# systemctl restart lightdm
#关闭lightdm
[root@webapp128 ~]# systemctl status lightdm