1 2 Previous Next 22 Replies Latest reply on Sep 20, 2018 10:30 AM by Quanwen Zhao Go to original post
      • 15. Re: xhost:  unable to open display ""
        Quanwen Zhao

        NIK 撰写:

         

        Hi.

        Mistake on step 3.

        You should initiate ssh session from you PC to Linux.

        You create session from Linux to Linux, so port 5901 was listen on Linux, not on PC.

         

        You can use any ssh client on your PC. For example: putty ( https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html )

         

        It can be running with same options as ssh or you can configure session with required options.

         

         

        Regards,

        Nik

         

        Hello, NIK

         

        Yep, I actually haven't done the Port forward on my PC.

         

        Afterwards I open the CMD window (my PC is OS of Windows 10 including ssh command) and directly input "ssh -L 5901:localhost:5995 vn-89D@192.168.210.10" and successfully connect to Linux Server.

         

        Next I use VNC viewer to connect the virtual desktop via "localhos:5901". This time it's finally Okay!

         

        Thank you very much.

         

        Best Regards

        Quanwen Zhao

        • 16. Re: xhost:  unable to open display ""
          Dude!

          Please follow the instructions at 3.5  Establishing the SSH Tunnel.

           

          As the document mentions, if you have the April 2018 update of Windows 10, you do not need to install any additional SSH client and can use SSH from Powershell or command prompt. Or use PuTTy as shown in Appendix A of the same document.

          1 person found this helpful
          • 17. Re: xhost:  unable to open display ""
            Quanwen Zhao

            Dude! 撰写:

             

            Please follow the instructions at 3.5 Establishing the SSH Tunnel.

             

            As the document mentions, if you have the April 2018 update of Windows 10, you do not need to install any additional SSH client and can use SSH from Powershell or command prompt. Or use PuTTy as shown in Appendix A of the same document.

             

            Hello, Dude!

             

            Apart from discussing your simple VNCpilot, I found that standard VNCserver's configuration has also generated a file "vncserver@:number.service" whatever on user root or oracle.

             

            But it's interesting that if I don't installed this grouplist "Server with GUI" on OL 7.5, there's nothing on that virtual desktop window via VNCviewer client tool (even no terminal window). Ortherwise it'll show a fully GUI. That's why? Does VNCserver need X11 and GUI?

             

            Because I have glanced at a special function calling terminal and xclock tool in your source code of VNCpilot and it'll not load more unnecessary GUI components and tools. It's obvious that you must deeply understand the concept of X11, VNC and GUI of Linux/Unix. However, till now I don't understand that concept very well. Certainly your source code is very nice and I really admire you.

             

            BTW how to transform your source code to RPM package? That's what I desire to know as well.

             

            Best Regards

            Quanwen Zhao

            • 18. Re: xhost:  unable to open display ""
              Dude!

              If you install server with GUI you install X Window and a user desktop. As I recall, screen sharing under Gnome is done by VINO, which is the VNC server for the GNOME desktop environment.

               

              Vncpilot however relies on TigerVNC, which provides a virtual desktop that can only be seen by a vnc viewer and hence does not need X Window on the server side. It's also mentioned in the Introduction. and I've posted more details about it at VNC

               

              You may be running more than one VNC server, and that's btw why Vncpilot uses display 95 in order not to interfere with any other VNC services you may have.

               

              BTW how to transform your source code to RPM package? That's what I desire to know as well.

              That's a different topic and a question how to create a RPM package. There is information about it on the web.

              1 person found this helpful
              • 19. Re: xhost:  unable to open display ""
                Dude!

                One more thing worth being mentioned. If you just install TigerVNC and set it up the usual way you are not getting something very useful, in particular as of OL/RHEL 7. For example, you will see font corruption and other issues when displaying the Oracle installer. To make using the remote virtual desktop a user friendly experience you also need a minimal window manager. Unfortunately, TWM was available in previous releases and does not function properly anymore. I created a RPM package because a few more things need to be installed, which are pulled in by defining RPM dependencies. All of this plus the question how to address VNC firewall, encryption and and security is a complex topic. It's not admin friendly. VNCpilot takes care of it. Sometimes you also only want temporary VNC access on demand.

                1 person found this helpful
                • 20. Re: xhost:  unable to open display ""
                  Quanwen Zhao

                  Dude! 撰写:

                   

                  One more thing worth being mentioned. If you just install TigerVNC and set it up the usual way you are not getting something very useful, in particular as of OL/RHEL 7. For example, you will see font corruption and other issues when displaying the Oracle installer. To make using the remote virtual desktop a user friendly experience you also need a minimal window manager. Unfortunately, TWM was available in previous releases and does not function properly anymore. I created a RPM package because a few more things need to be installed, which are pulled in by defining RPM dependencies. All of this plus the question how to address VNC firewall, encryption and and security is a complex topic. It's not admin friendly. VNCpilot takes care of it. Sometimes you also only want temporary VNC access on demand.

                   

                  Hi, Dude!

                   

                  Yep, here what you have mentioned is also my confusion thus I submit this post.

                   

                  On RHEL/OL 6 I also remembered that it hasn't issue such as never trying to set DISPLAY variable via VNCviewer for installing oracle software on user oracle, but on RHEL/OL 7 it is apparently different and   always warns you to set DISPLAY even I have connected to virtual desktop via VNCviewer.

                   

                  Thanks for your simple tool VNCpilot.

                   

                  Best Regards

                  Quanwen Zhao

                  • 21. Re: xhost:  unable to open display ""
                    Dude!

                    I have never experienced or seen any problem with the DISPLAY variable when using VNC. The purpose of the DISPLAY variable is to tell the X client or app the location of the X server. The X server connects to your screen and keyboard.

                     

                    You should not need to set the DISPLAY variable when using SSH with X11 forwarding or VNC. SSH with X11 forwarding as well as VNC automatically configure the appropriate DISPLAY variable.

                     

                    VNC will set the DISPLAY variable to the VNC server port that provides the connection to your VNC client. When you connect to a VNC service created by VNCpilot it will automatically set the DISPLAY to 95 (localhost). You can start the Oracle OUI or any X app without the need to configure DISPLAY.

                    1 person found this helpful
                    • 22. Re: xhost:  unable to open display ""
                      Quanwen Zhao

                      I have never experienced or seen any problem with the DISPLAY variable when using VNC. The purpose of the DISPLAY variable is to tell the X client or app the location of the X server. The X server connects to your screen and keyboard.

                       

                      You should not need to set the DISPLAY variable when using SSH with X11 forwarding or VNC. SSH with X11 forwarding as well as VNC automatically configure the appropriate DISPLAY variable.

                       

                      VNC will set the DISPLAY variable to the VNC server port that provides the connection to your VNC client. When you connect to a VNC service created by VNCpilot it will automatically set the DISPLAY to 95 (localhost). You can start the Oracle OUI or any X app without the need to configure DISPLAY.

                       

                      Hello, Dude!

                       

                      Yes, about using VNCpilot has no problem.

                       

                      But when I usually use the VINO of tigerVNC server (including GNOME desktop) and I create two services for Port 5901 and 5902 via VNC server (5901 is for root user and 5902 is for oracle).

                       

                      At this very moment the weird phenomenon has shown, such as this example on OL 7.5 as follows,

                       

                      (1)

                      1.png

                      (2)

                      2.png

                      3.jpg

                      (3)

                      4.png

                      5.png

                       

                      Best Regards

                      Quanwen Zhao

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