[Paraview] paraview - client-server

burlen burlen.loring at gmail.com
Mon Feb 8 22:03:20 EST 2010


I am curious to hear what Sean has to say.

But, say the batch system returns right away after the job is submitted, 
I think we can doctor the command so that it will live for a while 
longer, what about something like this:

    ssh -R XXXX:localhost:YYYY remote_machine "submit_my_job.sh && sleep
    100d"


pat marion wrote:
> Hey just checked out the wiki page, nice!  One question, wouldn't this 
> command hang up and close the tunnel after submitting the job?
>    ssh -R XXXX:localhost:YYYY remote_machine submit_my_job.sh
>   
> Pat
>
> On Mon, Feb 8, 2010 at 8:12 PM, pat marion <pat.marion at kitware.com 
> <mailto:pat.marion at kitware.com>> wrote:
>
>     Actually I didn't write the notes at the hpc.mil <http://hpc.mil>
>     link.
>
>     Here is something- and maybe this is the problem that Sean refers
>     to- in some cases, when I have set up a reverse ssh tunnel from
>     login node to workstation (command executed from workstation) then
>     the forward does not work when the compute node connects to the
>     login node.  However, if I have the compute node connect to the
>     login node on port 33333, then use portfwd to forward that to
>     localhost:11111, where the ssh tunnel is listening on port 11111,
>     it works like a charm.  The portfwd tricks it into thinking the
>     connection is coming from localhost and allow the ssh tunnel to
>     work.  Hope that made a little sense...
>
>     Pat
>
>
>     On Mon, Feb 8, 2010 at 6:29 PM, burlen <burlen.loring at gmail.com
>     <mailto:burlen.loring at gmail.com>> wrote:
>
>         Nice, thanks for the clarification. I am guessing that your
>         example should probably be the recommended approach rather
>         than the portfwd method suggested on the PV wiki. :) I took
>         the initiative to add it to the Wiki. KW let me know if this
>         is not the case!
>
>          
>         http://paraview.org/Wiki/Reverse_connection_and_port_forwarding#Reverse_connection_over_an_ssh_tunnel
>
>         Would you mind taking a look to be sure I didn't miss anything
>         or bollix it up?
>
>         The sshd config options you mentioned may be why your method
>         doesn't work on the Pleiades system, either that or there is a
>         firewall between the front ends and compute nodes. In either
>         case I doubt the NAS sys admins are going to reconfigure for
>         me :) So at least for now I'm stuck with the two hop ssh
>         tunnels and interactive batch jobs. if there were someway to
>         script the ssh tunnel in my batch script I would be golden...
>
>         By the way I put the details of the two hop ssh tunnel on the
>         wiki as well, and a link to Pat's hpc.mil <http://hpc.mil>
>         notes. I don't dare try to summarize them since I've never
>         used portfwd and it refuses to compile both on my workstation
>         and the cluster.
>
>         Hopefully putting these notes on the Wiki will save future
>         ParaView users some time and headaches.
>
>
>         Sean Ziegeler wrote:
>
>             Not quite- the pvsc calls ssh with both the tunnel options
>             and the commands to submit the batch job.  You don't even
>             need a pvsc; it just makes the interface fancier.  As long
>             as you or PV executes something like this from your machine:
>             ssh -R XXXX:localhost:YYYY remote_machine submit_my_job.sh
>
>             This means that port XXXX on remote_machine will be the
>             port to which the server must connect.  Port YYYY (e.g.,
>             11111) on your client machine is the one on which PV
>             listens.  You'd have to tell the server (in the batch
>             submission script, for example) the name of the node and
>             port XXXX to which to connect.
>
>             One caveat that might be causing you problems, port
>             forwarding (and "gateway ports" if the server is running
>             on a different node than the login node) must be enabled
>             in the remote_machine's sshd_config.  If not, no ssh
>             tunnels will work at all (see: man ssh and man
>             sshd_config).  That's something that an administrator
>             would need to set up for you.
>
>             On 02/08/10 12:26, burlen wrote:
>
>                 So to be sure about what you're saying: Your .pvsc
>                 script ssh's to the
>                 front end and submits a batch job which when it's
>                 scheduled , your batch
>                 script creates a -R style tunnel and starts pvserver
>                 using PV reverse
>                 connection. ? or are you using portfwd or a second ssh
>                 session to
>                 establish the tunnel ?
>
>                 If you're doing this all from your .pvsc script
>                 without a second ssh
>                 session and/or portfwd that's awesome! I haven't been
>                 able to script
>                 this, something about the batch system prevents the
>                 tunnel created
>                 within the batch job's ssh session from working. I
>                 don't know if that's
>                 particular to this system or a general fact of life
>                 about batch systems.
>
>                 Question: How are you creating the tunnel in your
>                 batch script?
>
>                 Sean Ziegeler wrote:
>
>                     Both ways will work for me in most cases, i.e. a
>                     "forward" connection
>                     with ssh -L or a reverse connection with ssh -R.
>
>                     However, I find that the reverse method is more
>                     scriptable. You can
>                     set up a .pvsc file that the client can load and
>                     will call ssh with
>                     the appropriate options and commands for the
>                     remote host, all from the
>                     GUI. The client will simply wait for the reverse
>                     connection from the
>                     server, whether it takes 5 seconds or 5 hours for
>                     the server to get
>                     through the batch queue.
>
>                     Using the forward connection method, if the server
>                     isn't started soon
>                     enough, the client will attempt to connect and
>                     then fail. I've always
>                     had to log in separately, wait for the server to
>                     start running, then
>                     tell my client to connect.
>
>                     -Sean
>
>                     On 02/06/10 12:58, burlen wrote:
>
>                         Hi Pat,
>
>                         My bad. I was looking at the PV wiki, and
>                         thought you were talking about
>                         doing this without an ssh tunnel and using
>                         only port forward and
>                         paraview's --reverse-connection option . Now
>                         that I am reading your
>                         hpc.mil <http://hpc.mil> post I see what you
>                         mean :)
>
>                         Burlen
>
>
>                         pat marion wrote:
>
>                             Maybe I'm misunderstanding what you mean
>                             by local firewall, but
>                             usually as long as you can ssh from your
>                             workstation to the login node
>                             you can use a reverse ssh tunnel.
>
>
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