1、检查是否安装VNC

[root@localhost ~]# yum install -y vnc vnc-server

2、[root@localhost ~]# chmod 777 root/.vnc/xstartup

3、修改vnc 分辨率:

vi /usr/bin/vncserver：

$geometry = "1200x700"

4、修改 /root/.vnc/xstartup

#!/bin/sh

# Uncomment the following two lines for normal desktop:

unset SESSION_MANAGER

exec /etc/X11/xinit/xinitrc

[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
xterm -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
twm &

5、配置VNC

[root@localhost ~]#  cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:1.service 

[root@localhost ~]# vi /etc/sysconfig/vncservers

# THIS FILE HAS BEEN REPLACED BY /lib/systemd/system/vncserver@.service
VNCSERVERS="1:root"
VNCSERVERARGS[1]="-geometry 800x600"

VNCSERVERS="2:oracle"
VNCSERVERARGS[1]="-geometry 800x600"

 [root@localhost ~]# vi /etc/systemd/system/vncserver@:1.service

#将<USER>替换成用户root：

ExecStart=/usr/sbin/runuser -l root -c "/usr/bin/vncserver %i"
PIDFile=/home/root/.vnc/%H%i.pid

重启systemd：

[root@localhost ~]# systemctl daemon-reload

永久开启VNC服务： 

[root@localhost ~]# systemctl enable vncserver@1.service
Created symlink from /etc/systemd/system/multi-user.target.wants/vncserver@1.service
to /usr/lib/systemd/system/vncserver@.service.

6、启动VNC服务（解决xhost:unable to open display）

[root@localhost ~]# vncserver

New 'localhost:1 (root)' desktop is localhost.localdomain:1

Starting applications specified in /root/.vnc/xstartupLog file is /root/.vnc/localhost:1.log

[root@localhost ~]# export DISPLAY=localhost.localdomain:1

[root@localhost ~]# xhost +

access control disabled, clients can connect from any host

再进入oracle用户（安装Oracle时需要图形化界面）

[oracle@localhost ~]$ export DISPLAY=localhost:1
[oracle@localhost ~]$ xhost +
access control disabled, clients can connect from any host

注意：一定要在root用户下先启动vnc并配置diaplay，执行xhost +，再进入oracle用户进行操作

7、关闭VNC服务

[root@localhost ~]# ps -ef|grep -i vnc     （查看vnc的进程号）
root       5055      1  0 16:26 tty1     00:00:13 /bin/Xvnc :1 -auth /root/.Xauthority -desktop localhost.localdomain:1
(root) -fp catalogue:/etc/X11/fontpath.d -geometry 1200x700 -pn -rfbauth /root/.vnc/passwd -rfbport 5901 -rfbwait 30000
root       5748   5717  0 17:06 pts/0    00:00:00 grep --color=auto -i vnc
[root@localhost ~]# kill -9 5055     （通过杀掉进程关闭vnc）

或者：

[root@localhost ~]# vncserver -kill :3    #注意这里冒号前有空格，推荐这种方法
Killing Xvnc process ID 8083

8、删除无效的vnc端口

[root@localhost ~]# cd /tmp/.X11-unix/
[root@localhost .X11-unix]# ls
X1  X2  X3
[root@localhost .X11-unix]# rm X*
rm: remove socket  X1 ? Y
rm: remove socket  X2 ? Y
rm: remove socket  X3 ? Y
[root@localhost .X11-unix]# ls
[root@localhost .X11-unix]#