[Users] OOM and /etc/vz/oom-groups.conf

[Kir Kolyshkin]

On 10/02/2013 10:10 AM, Mark J. wrote:
> On Tue, Oct 01, 2013 at 04:37:52PM -0700, Kir Kolyshkin wrote:
>> I'd suggest you to reproduce the bug on 081.3 kernel booted for real,
>> and if you succeed, file a kernel bug to bugzilla.openvz.org.
> Will put in the request to try and get one upgraded (or next node build on the new kernel)
>
>> Also, it would be helpful to see output of pstree or ps axf inside a
>> container.
>> Note that you have specified oom adjustment for mysqld processes
>> which parent is init. I guess that OOM killer kills a mysqld process
>> which parent is not init, so oom adj is not applied.
> ps axf:
>
<...skipped...>
> 15195 ?        S      0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/server.noticias365.net.pid
> 31661 ?        Sl     1:43  \_ /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --log-error=/var/log/mysql.error.log --open-files-limit=8192 --pid-file=/var/lib/mysql/server.noticias365.net.pid --socket=/tmp/mysql.sock --port=3306

As you can see, mysqld parent is not "init" as it is set in config file,
but "mysqld_safe", therefore the rule is not applicable.

>> Generally speaking, I think you are doing something wrong here.
>>
>> First, mysqld is a service which controls its own memory consumption
>> pretty well, you just need to set a few parameters in its /etc/my.cnf,
>> and that would be the preferred way of managing it.
> These do have tweaked my.cnf files for cPanel.
>
>> Second, OOM should not happen in general. In case you are using
>> vswap, the sum of ram and swap configured for all containers
>> should not exceed real ram and swap on the system. Worst case
>> scenario is swap will be used heavily, resulting in a slowdown
>> (which is still way better than killing processes). In case you are
>> not using VSwap -- well, you should, see http://openvz.org/VSwap.
>>
> These are vswap enabled VM's and the nodes do have the /proc/vz/vswap file. If I need to tweak the conf files more thats not a problem.

Well, the question is if CT config is VSwap or not.

Please show CT config file.