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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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  • W Offline
    W Offline
    white_rabbit
    wrote on last edited by
    #1

    Hi.
    When I check the status von veyon on an Ubuntu 20.04 client I get this:

    sudo systemctl status veyon
    ● veyon.service - Veyon Service
         Loaded: loaded (/lib/systemd/system/veyon.service; enabled; vendor preset: enabled)
         Active: active (running) since Thu 2021-05-27 11:09:42 CEST; 26min ago
           Docs: man:veyon-service(1)
       Main PID: 1519 (veyon-service)
          Tasks: 9 (limit: 9404)
         Memory: 46.3M
         CGroup: /system.slice/veyon.service
                 ├─ 1519 /usr/bin/veyon-service
                 └─81496 /usr/bin/veyon-worker {8e997d84-ebb9-430f-8f72-d45d9821963d}
    
    Mai 27 11:09:42 raum1-pc systemd[1]: Started Veyon Service.
    Mai 27 11:09:42 raum1-pc veyon-service[1519]: Attribute Qt::AA_ShareOpenGLContexts must be set before QCoreApplication is >
    
    

    I'm not sure but is it possible (as a consequence of the last error) that veyon-server doesn't start?
    Thank you?

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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.

      W 1 Reply Last reply
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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!

            H 1 Reply Last reply
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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

                H 1 Reply Last reply
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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 😉

                    H 2 Replies Last reply
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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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