Changes between Version 33 and Version 34 of vnc3d


Ignore:
Timestamp:
04/05/16 09:42:46 (8 years ago)
Author:
Jens Henrik Goebbert
Comment:

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  • vnc3d

    v33 v34  
    4949
    5050VNC offers the ability to detach from a session (running in a VNC server) and then attach back at a later time. \\
    51 That means, that the user can close the VNC viewer on his/her computer and any application started in the VNC session on the server keeps on running. They do not pause or even be killed. \\
     51That means, that the user can close the VNC viewer on his/her computer and any application started in the VNC session on the server keeps on running - they do not pause or even be killed. \\
    5252Later on the user can connect back to the same VNC session (even from a different computer) and keep on working. \\
    5353
     54[[Image(Trac_Setup_VNC.png, 640px)]]\\
    5455
    5556==== hardware accelerated rendering (OpenGL)
    56 [[Image(https://upload.wikimedia.org/wikipedia/commons/thumb/6/67/X11transport.png/600px-X11transport.png, 100px, align=right, margin=0)]]
     57[[Image(https://upload.wikimedia.org/wikipedia/commons/thumb/6/67/X11transport.png/600px-X11transport.png, 200px, align=right, margin=0)]]
    5758Whenever an OpenGL capable visualization software, like !VisIt, is started on the remote cluster node, \\
    58 OpenGL commands can be redirected to the GPU of this node with the help of [http://www.virtualgl.org VirtualGL] (using the command '''vglrun'''). \\
     59OpenGL commands can be redirected to the GPU of this node with the help of [http://www.virtualgl.org VirtualGL]. \\
     60* ... using '''vglrun''' (e.g. vglrun paraview)
    5961This way the hardware accelerated rendering capabilities of a cluster node (if available) can be exploit for remote rendering. \\
    6062(attention: __without__ VirtualGL software, rendering using the CPU instead of the GPU must be used (if available), which is much slower).
    6163
    62 [[Image(Trac_Setup_VNC.png, 640px)]]\\
    6364
    64 The following steps are necessary to start a VNC session for remote rendering with !VisIt on JURECA.
     65The following steps are necessary to start a VNC session for remote rendering with !VisIt on JURECA. \\
    6566Please notice that the VNC server is only available on vis-nodes!
    6667
    67 ==== prerequisite: Create a VNC password and a startup script on JURECA
    68 This step is a prerequisite for using VNC and has only to be done '''once'''.
    69 
    70 The aim of this step is to create a VNC password and a very small (one line) VNC startup script to start the [http://www.xfce.org/?lang=en Xfce] desktop environment. \\
    71 As all VNC related commands are only available on a vis-node, one has to allocate a vis-node first and then start an interactive shell and execute the necessary commands there. \\
    72 It works as follows:
    73 
    74 {{{ #!sh
    75 # request allocation on visualization node ('vncpasswd' only available on vis-nodes)
    76 salloc -N 1 -p vis --gres=gpu:0
    77 
    78 # spawn interactive application 'bash' on the visualization node
    79 srun -n 1 --pty /bin/bash -i
    80 
    81 # create .vnc directory in HOME
    82 mkdir ~/.vnc
    83 cd ~/.vnc
    84 
    85 # create VNC password for later authentication when connecting VNC viewer with VNC server
    86 vncpasswd # -> type in your VNC password (which will be stored in ~/.vnc/passwd)
    87 
    88 # create/overwrite xstartup-script
    89 echo "exec startxfce4" > ~/.vnc/xstartup
    90 
    91 # exit job and release allocation
    92 exit
    93 exit
    94 }}}
    95 
    9668=== 1. Start VNC server on a vis node
    97 Open an ssh shell on a login node of JURECA the usual way.\\
     69Open an ssh shell on any login node of JURECA the usual way.\\
    9870
    9971salloc is used to request an allocation. When the job is started, a shell (or other program specified on the command line) is started on the submission host (login node). From the shell srun can be used to interactively spawn parallel applications. The allocation is released when the user exits the shell.
    … …  
    10375# request allocation and spawn VNC server on visualization node
    10476salloc -N 1 -p vis --gres=mem512,gpu:1 --start-xserver --time=1:00:00
    105 srun -n 1 --cpu_bind=none --gres=gpu:1 vncserver -fg -geometry 1920x1080
     77srun -n 1 --cpu_bind=none --gres=gpu:1 vncserver -fg -profile vis -geometry 1920x1080
    10678}}}
     79salloc/srun options
    10780* -N 1            -> Set number of requested nodes.
    10881* -p vis          -> Limit request to nodes from the visualization partition.
    … …  
    11386* Please check 'salloc --help' and 'srun --help' for more details.
    11487
     88vncserver options
     89* -fg             -> start VNC server in the foreground (ensure the end of job-script is not reached, as this will stop the job)
     90* -profile        -> choose a profile (eg. default, vis)
     91* -geometry       -> set the screen size (optional)
     92
    11593In case the VNC server could successfully be started, you will get an output like:
    116 {{{ #!ShellExample
    117 > New 'jrc1391:1 (<USER>)' desktop is jrc1391:1
    118 >
    119 > Starting applications specified in ${HOME}/.vnc/xstartup
    120 > Log file is ${HOME}/.vnc/jrc1391:1.log
     94{{{ #!sh
     95Desktop 'TurboVNC: jrc1384.zam.kfa-juelich.de:1 (<USERID>)' started on display jurecavis01.fz-juelich.de:1
    12196}}}
    12297