[Paraview] paraview - client-server

Mon Feb 8 20:45:07 EST 2010

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> wrote:

> Actually I didn't write the notes at the 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> 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 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 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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>>
>
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