问题还原
[root@Oracle19c ~]# echo $DISPLAY
192.168.189.246:0.0
[root@Oracle19c ~]# xhost +
xhost: unable to open display "192.168.189.246:0.0"
问题解决方法
[root@Oracle19c ~]# export DISPLAY=:0
[root@Oracle19c ~]# xhost +
xhost: unable to open display ":0"
[root@Oracle19c ~]# export DISPLAY=192.168.189.246:0.0
[root@Oracle19c ~]#
[root@Oracle19c ~]# echo $DISPLAY
192.168.189.246:0.0
[root@Oracle19c ~]# xhost +
access control disabled, clients can connect from any host