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  3. veyon-server doesn't start (Qt::AA_ShareOpenGLContexts must be set before QCoreApplication)

veyon-server doesn't start (Qt::AA_ShareOpenGLContexts must be set before QCoreApplication)

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  • T Offline
    T Offline
    tobydox
    wrote on last edited by
    #2

    This is just a warning which has been fixed in Veyon 4.5.6 but unfortunately it's not related to the server start problem 😞

    Did you already try to enable advanced the "Write to logging system of operating system" option (https://docs.veyon.io/en/latest/admin/reference.html#logging) and change the log level to debug? You should then see the output of the veyon-server process in the veyon-service unit's journal. If the program catchsegv is in PATH, it will be used to dump a possible backtrace of the server if it crashes.

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    • W Offline
      W Offline
      white_rabbit
      replied to tobydox on last edited by white_rabbit
      #3

      @tobydox
      Hi. I enabled the Logfiles in Debug-Mode.
      Now I found this:

       /tmp]$ tail  VeyonService.log
      
      2021-05-29T11:52:41.093: [INFO] LinuxServiceCore::startServer(): Starting server for new session "/org/freedesktop/login1/session/_32" with ID 0 at seat "/org/freedesktop/login1/seat/seat0"
      2021-05-29T11:55:20.873: [ERR] LinuxServiceCore::startServer(): Can't start Veyon Server in Wayland sessions as this is not yet supported. Please switch to X11-based sessions!
      2021-05-29T11:55:23.198: [DEBUG] PlatformSessionManager::closeSession(): Closing session 0 for platform session "/org/freedesktop/login1/session/_32"
      2021-05-29T11:55:23.198: [INFO] LinuxServiceCore::stopServer(): stopping server for removed session "/org/freedesktop/login1/session/_32"
      2021-05-29T11:55:35.946: [DEBUG] LinuxServiceCore::startServ
      

      When I observe the process veyon-service with catchsegv I found this:

      29/05/2021 12:12:03 Xinerama: number of sub-screens: 1
      29/05/2021 12:12:03 Xinerama: no blackouts needed (only one sub-screen)
      29/05/2021 12:12:03 
      
      X11 MIT Shared Memory Attach failed:
        Is your DISPLAY=:0 on a remote machine?
        Suggestion, use: x11vnc -display :0 ... for local display :0
      
      caught X11 error:
      29/05/2021 12:12:03 deleted 32 tile_row polling images.
      X Error of failed request:  BadAccess (attempt to access private resource denied)
        Major opcode of failed request:  130 (MIT-SHM)
        Minor opcode of failed request:  1 (X_ShmAttach)
        Serial number of failed request:  57
        Current serial number in output stream:  91
      
      

      And afterwards the same with veyon-server:

      2021-05-29T12:15:35.158: [DEBUG] VeyonCore::initSystemInfo(): "4.5.5" "fossa.my-domain.de" "linux" "5.8.0-53-generic" "Ubuntu 20.04.2 LTS" "ubuntu" "20.04"
      2021-05-29T12:15:35.166: [ERR] VncServer::VncServer(): no VNC server plugins found!
      2021-05-29T12:15:35.196: [DEBUG] [KLDAP] connection closed!
      2021-05-29T12:15:35.196: [DEBUG] [KLDAP] ldap url: "ldap://server.my-domain.de:3268"
      2021-05-29T12:15:35.197: [DEBUG] [KLDAP] setting version to: 3
      2021-05-29T12:15:35.197: [DEBUG] [KLDAP] setting timeout to: 0
      2021-05-29T12:15:35.197: [DEBUG] [KLDAP] setting security to: 1
      2021-05-29T12:15:35.197: [DEBUG] [KLDAP] start TLS
      2021-05-29T12:15:35.264: [DEBUG] [KLDAP] setting sizelimit to: 0
      2021-05-29T12:15:35.264: [DEBUG] [KLDAP] setting timelimit to: 0
      2021-05-29T12:15:35.264: [DEBUG] [KLDAP] initializing SASL client
      2021-05-29T12:15:35.264: [DEBUG] [KLDAP] binding to server, bindname:  "<MY-SAMBA-DOMAIN>\\admin"  password: *****
      2021-05-29T12:15:35.264: [DEBUG] [KLDAP] ldap_sasl_bind_s (simple)
      2021-05-29T12:15:35.303: [DEBUG] FeatureWorkerManager::startUnmanagedSessionWorker(): Starting worker (unmanaged session process) for feature QUuid("{8e997d84-ebb9-430f-8f72-d45d9821963d}")
      2021-05-29T12:15:35.304: [DEBUG] FeatureWorkerManager::sendMessageToUnmanagedSessionWorker(): User session likely not yet available - retrying worker start
      2021-05-29T12:15:35.304: [DEBUG] VncProxyServer::start(): started on port 11100
      2021-05-29T12:15:35.304: [DEBUG] VncServer::prepare():
      2021-05-29T12:15:35.304: [DEBUG] VeyonCore::exec(): Running
      2021-05-29T12:15:35.305: [DEBUG] VeyonCore::exec(): Exit
      2021-05-29T12:15:35.305: [DEBUG] ComputerControlServer::~ComputerControlServer():
      2021-05-29T12:15:35.305: [DEBUG] VncServer::~VncServer():
      2021-05-29T12:15:35.305: [DEBUG] Logger::~Logger(): Shutdown
      PluginManager::~PluginManager():
      CryptoCore::~CryptoCore():
      KLDAP: connection closed!
      
      

      Is this helpful?

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      • T Offline
        T Offline
        tobydox
        wrote on last edited by
        #4

        Can you try to add -noshm as additional custom x11vnc parameter in the advanced VNC server configuration?

        W S 2 Replies Last reply
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        • W Offline
          W Offline
          white_rabbit
          replied to tobydox on last edited by
          #5

          @tobydox said in veyon-server doesn't start (Qt::AA_ShareOpenGLContexts must be set before QCoreApplication):

          -noshm

          Wow -- I think that's the solution! I just added this option and restarted the Client -- now "htop" shows a running veyon-server ... I can't test it in our productive environment at the moment but it looks good so far! Thank you!

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          • H Offline
            H Offline
            hammergil
            replied to white_rabbit on last edited by
            #6

            @white_rabbit where do you add this parameter? Is it in the Veyon configuration interface somewhere?

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            • T Offline
              T Offline
              tobydox
              replied to hammergil on last edited by tobydox
              #7

              The VNC server section is correct, make sure to enable advanced view in the menu and to select "Builtin VNC server":

              noshm.jpg

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              • H Offline
                H Offline
                hammergil
                replied to tobydox on last edited by
                #8

                @tobydox the master computer is running Windows 10 and does not have an option for parameters. The built-in vnc is UltraVNC.
                1f9424b3-5656-4fac-8922-44091538f68a-image.png

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                • T Offline
                  T Offline
                  tobydox
                  replied to hammergil on last edited by
                  #9

                  @hammergil

                  Since the Linux-based student computers are affected, you have to make the configuration changes on them directly 😉

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                  • H Offline
                    H Offline
                    hammergil
                    replied to tobydox on last edited by
                    #10

                    @tobydox Great! That did it! Thanks for the help!

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                    • H Offline
                      H Offline
                      hammergil
                      replied to tobydox on last edited by
                      #11

                      @tobydox what does the parameter "-noshm" mean out of curiosity.

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                      • S Offline
                        S Offline
                        stephanvaningen
                        replied to tobydox on last edited by
                        #12

                        @tobydox nice. This solved an issue I've been struggling with for quite q few days:) thanks!

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