[torqueusers] Re: [Mauiusers] potential of misuse with interactive jobs

Neelesh Arora narora at Princeton.EDU
Thu Oct 19 12:14:40 MDT 2006


Garrick Staples wrote:
> On Wed, Oct 18, 2006 at 04:05:24PM -0400, Neelesh Arora alleged:
>> Hi All,
>>
>> In a setup like ours:
>> multiple queues with different max_cputime limits, users specify 
>> required cputime, jobs get routed accordingly
>> there is a potential of resource hoarding, in that a user may submit an 
>> interactive job with very high cputime and block a node for future use. 
>> Since the job does not accrue cputime, it is not effected by the queue's 
>> max_cputime limit.
>>
>> We would like to avoid this scenario and I can think of 2 ways to do it:
>> - route interactive jobs to a separate queue (with limited max_cputime)
>> - identify an interactive job at submission and set a very low walltime 
>> (similar to above)
>> - disable interactive jobs at the server level
>>
>> I am afraid I can't find the way to achieve any of these. Can someone 
>> please apprise me how this can be done? How do others avoid such misuse?
> 
> There isn't a way to enforce policy based on interactive jobs.
> 
> Btw, understand that such a feature would always be trivial to bypass.  
> Users can run the exact same commands in interactive and batch jobs.  My
> own users like to do naughty things like this:
> 
>   echo sleep 999999 | qsub
> 
> The smarter ones do this:
>   echo screen -m -D | qsub
> 
> The best solution to these things is this:
>   qselect -u <username> | xargs qdel
>   chsh <username> /bin/false

While I agree that there will always be users who would try to act 
smart, but that does not mean that shared systems like Torque should not 
provide countermeasures. In particular, when it happens to be a misuse 
of a feature of such a system. If there is a potential of misuse of 
interactive jobs to bypass all fairshare/priority/usage based policies, 
then a workaround should be offered.

Besides, having the ability to route jobs based on whether they are 
batch or interactive is a useful job management feature in itself. So, I 
guess I am asking for a couple of feature additions to Torque here.

Would the powers that be please comment on how much work it would be to 
add the ability to a) route jobs based on their type and/or b) disable 
interactive jobs at the server level.

Thanks.

-Neel


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