Preventing a single student programmer from choking the whole server.

[Josh Roden]

Hi
I see some explanation about cgroups on Centos 6 here:
https://www.digitalocean.com/community/tutorials/how-to-limit-resources-using-cgroups-on-centos-6
I will check about its implementation for Centos 6 and update my post.
Thanks for giving a direction.
Josh

On Fri, Apr 21, 2017 at 4:27 PM, guy keren <guy.choo.keren at gmail.com> wrote:

>
> how about using cgroups, putting each user's login shell in a cgroup that
> cannot use more then X% of the whole CPUs. this will affect all processes
> spawned under the user's shell.
>
> --guy
>
>
> On 04/21/2017 03:07 PM, Josh Roden wrote:
>
>> Hi
>>
>> server setup:
>> ------------------
>> Centos 6
>> 32GB RAM
>> 16 Cpu's
>> 70 students max
>>
>> I am using /etc/security/limits.conf to prevent the students from
>> choking the whole
>> server but sometimes one student will write a very bad program that
>> somehow
>> runs itself again and again - so fast that "killall" and "pkill -9 -u"
>> can't stop/remove
>> the user fast enough before the student's program is run again and
>> again...
>>
>> Here is my definition in limits:
>>
>>  @stud           hard    cpu             8
>>  @stud           hard    nproc           256
>>  @stud           hard    nofile          1024
>>  @stud           -       maxlogins       6
>>
>> I can't reduce cpu time below 8min because eclipse will be killed every
>> hour or so.
>> My problem seems to be that the student can run up to 256 processes that
>> each
>> uses 100% of a single CPU and we only have 16 CPU''s.
>>
>> Thanks for any suggestions.
>> Josh
>>
>>
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>>
>>
>
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