CENTOS7 VPN ORACLE DISPLAY

[ouxoux2]

Hi everybody,

I am new in the field of linux, oracle, centos and servers.
Before i post this, i allready have read many solutions that didnt solve my problems. Note that as i am a beginner i do not understand yet all the interactions in the system.

So i want to install oracle 12c Release 2 on a centOS server with GUI. I need GUI for the configuration and installation of oracle.
I proceeded as follows:

I- I first have installed a VM localy on my computer to try and test, i followed a tutorial from tecmint: i installed centos with GUI, when i was to install oracle i had a problem with the display variable that wasn't initialized, but the solution were easy one had to set it to 0.0 and than it worked, i have installaed oracle and everything was fine.

II- I wanted to do the same but directly after having installed the VM on the server, therefore i did the same thing, i configurated VNC to allow the communication from the server to my computer, this all worked good, i did everything as i did while it was localy installed. When i connect with VNC and i trx to run the oracle installation file, i had the same error as localy, i then tried to solve it the same way but that did not work.


Now i want to ask one question about how you think one can solve it? so someone have an idea?
Until now, I understood that centOS is our server, we instslled VNC to allow graphical communication with the local pc, this worked very good, but i dont understand well the display variabel. I read that this was about to set up the path for the graphical representation, but the thing that i dont understand is that the graphical representation works already good with VPN.

[TrevorH]

Your vnc session uses its own DISPLAY in addition to the one on the local console. When you set up your vnc systemd unit file, you probably had to tell that the display number to use - most likely it'll be 1.0 but really on a properly set up and running GUI system, DISPLAY should already be set to the right value as long as you start the terminal you use for this from the display itself.

[ouxoux2]

Hi Trevor,

Thanks for replying, i tryed to export the display as 1.0, but i still got the same error!
Another idea?

[TrevorH]

So you are connecting via VNC, what do you do once you have connected?

I just installed tigervnc-server here and running systemctl cat vncserver@:1.service show me that it has a unit file that would start up display :1 (also :2 - :9 seem to be set up too).

[ouxoux2]

Hi Trevor,

Thanks for replying, when i connect via VNC, i connect with an oracle account that i have created, (username : oracle) and execute the installation file for oracle /stage/database/runInstaller such as described in https://www.tecmint.com/install-oracle- ... -centos-7/ step number 7, i then become the error that the verification of the screen features has failed: the screen has to output at least 256 colours.. and that i have to solve this problem before continyung through verifying the display variable.

I had the problem when i did the same thing but localy in a VM, and this was solved by setting the display value by 0, with the root user.

If i reply continue even if condition not verified i become the following error: can't connect to windows x11 server using :1.0 as the value of the display.. i tryed many values such as 0.0 or the IP of my computer..

[TrevorH]

So, I set up tigervnc-server and copied and amended the supplied unit file as per the instructions using systemctl edit --full vncserver@:1 then did a daemon-reload and started up vncserver@:1. Opened the ports in iptables and connected and get a full gnome3 desktop. From there I select Applications -> Favorites -> Terminal to get a command prompt and from there I ran echo $DISPLAY and it says ":1". I also ran xwininfo then clicked on any window with the mouse and it shows me output that include "Depth: 32" which shows it's using 32 bit colour (256 colours is 16 bit).

[ouxoux2]

Thanks for reply, indeed it worked while setting display to 1.0, but it worked only after rebooting the server, thank you very mutch