[GE users] qlogin / ssh (ultimately, X forwarding)

rumpelkeks tina.friedrich at diamond.ac.uk
Thu Feb 4 17:27:42 GMT 2010

Sorry. Use Head. MPI uses qrsh, not qlogin, doesn't it? So changing the 
qlogin but leaving the qrsh alone is indeed the way forward, I guess.

Again, thanks a lot.


rumpelkeks wrote:
> Another thing.
> Doesn't MPI tight integration use qlogin? So would setting the qlogin 
> method to ssh globally break that, possibly?
> Sorry for being a bother :)
> Tina
> rumpelkeks wrote:
>> Hi,
>> I was wanting to avoid ssh due to the integration/accounting/etc issues, 
>> especially on the 'new' nodes.
>> The issue about "Potential loss of control: in some unusual cases, 
>> killing the job might leave behind idle or busy processes, even if the 
>> job is seen as finished by Grid Engine." mentioned in the disadvantages 
>> on the how to set it up page, how often would you say do you actually 
>> see that? That was one of my biggest gripes with it (regarding using 
>> that method on the faster nodes).
>> How far away is the builtin supporting X, actually?
>> Thanks a lot for your help,
>> Tina
>> reuti wrote:
>>> Hi,
>>> Am 04.02.2010 um 11:19 schrieb rumpelkeks:
>>>> <snip>
>>>> Okay. I didn't read it like that, again that's down to me not being  
>>>> good
>>>> of putting the puzzle together.
>>>> So there's definitely no way to only have part of the hosts in a queue
>>>> do that? Is there a way to only allow it on parts of a queue?
>>> in long-term also the -builtin- method will support X11 forwarding IIRC.
>>>> Basically, what I have is the - not unusual - case of having a  
>>>> group of
>>>> more elderly hosts and new, fast nodes. On the new, fast nodes, we run
>>>> automatic fast data processing and such; the older ones aren't in use
>>>> for the fast processing jobs any more. So I don't see any harm in
>>>> allowing people to run X applications on the older hosts; but I'd like
>>>> to keep the newer hosts used for fast processing free of them, if  
>>>> at all
>>>> possible. I thought (hoped?) that I could set it up so that only the
>>>> older hostgroup uses the ssh method (clearly, I was wrong). Is  
>>>> there any
>>>> way you can see of doing this? I wouldn't really like to set up a
>>>> different queue for it (I've got too many queues as it is, in my  
>>>> opinion).
>>> I would suggest to use ssh for all nodes, but adjust /etc/ssh/ 
>>> sshd_config to disallow X11 on certain machines (assuming that  
>>> interactive usage is allowed on all nodes besides this restriction).  
>>> If you don't want to tamper the original sshd_config, it's also  
>>> possible to supply a custom one for the SGE created sessions with the  
>>> -f option to sshd in SGE's qrsh setup or to append just the necessary  
>>> -oX11Forwarding=no in the local configuration for the disallowed  
>>> nodes to the qrsh_daemon entry.
>>>>> What you can set up is to use ssh for the interactive qlogin/rlogin,
>>>>> and -builtin- for qrsh with command (i.e. the rsh_* entries).
>>>> Or, I assume, qlogin with builtin and qrsh using the ssh method? (I  
>>>> want
>>>> the ssh/X forwarding to be the exception rather than the norm).  
>>>> Could I
>>>> then disallow qrsh on some host groups?
>>> You could remove the keyword "INTERACTIVE" from the qtype entry in  
>>> the queue definition. But this will not disallow interactive use when  
>>> users find out to get an interactive slot with:
>>> $ qrsh -now n
>>> it will then run in a batch queue. "INTERACTIVE" in SGE terms is more  
>>> to be read as "IMMEDIATE" (and a `qsub -now y ..` will run in an  
>>> interactive queue).
>>> In the sshd_config you can use one of the "AllowUsers" or  
>>> "AllowGroups" options to restrict access though.
>>> -- Reuti
>>> ------------------------------------------------------
>>> http://gridengine.sunsource.net/ds/viewMessage.do?dsForumId=38&dsMessageId=243197
>>> To unsubscribe from this discussion, e-mail: [users-unsubscribe at gridengine.sunsource.net].

Tina Friedrich, Computer Systems Administrator, Diamond Light Source Ltd
Diamond House, Harwell Science and Innovation Campus - 01235 77 8442


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