[lxc-users] sysctl -p no longer allowed in container

[Dan Kegel]

Just tried a ubuntu 15.10 host, and at first glance, it gives ubuntu
15.10 *and* ubuntu 12.04 guests sufficient semaphores right from the
start, so I don't need to do anything.

Ubuntu 14.04 is dead, long live Ubuntu 15.10 :-)

Um, well, actually, 14.04 isn't dead yet.  Is something missing from backports?
Could we get this goodness on 14.04?
- Dan

On Fri, Dec 11, 2015 at 9:15 AM, Dan Kegel <dank at kegel.com> wrote:
> Alas, it was the lack of coffee, or wishful thinking.  I must have
> been typing in the wrong terminal.
>
> I guess my next step is to try this on an ubuntu 15.10 host and see if
> everything just works there.
> - Dan
>
> On Fri, Dec 11, 2015 at 8:10 AM, Dan Kegel <dank at kegel.com> wrote:
>> I did, but it was a slightly older version from the ppa.
>>
>> Updating lxc and lxcfs to the one in trusty-backports, and then
>> creating a new container, seems to have helped!
>>
>> $ apt-cache policy lxcfs
>> lxcfs:
>>   Installed: 0.11-0ubuntu3~ubuntu14.04.1
>> $ sudo lxc-create -t download -n ubu1510-x -- --dist ubuntu --release
>> wily --arch amd64
>> ...
>> $ cat /proc/sys/kernel/sem
>> 250 65536 32 32768
>> $ ssh ubu1510-x
>> $ cat /proc/sys/kernel/sem
>> 250 65536 32 32768
>>
>> I haven't figured out how to endow an old container with higher sem
>> settings yet...
>> diff on the config files and etc didn't immediately illuminate the
>> way, as the old container's a bit dirty.
>> But I can live with recreating them.
>>
>> Let's hope I'm not just short on coffee this morning, and this really
>> did fix the problem :-)
>> - Dan
>>
>> On Thu, Dec 10, 2015 at 11:09 PM, Fajar A. Nugraha <list at fajar.net> wrote:
>>> On Fri, Dec 11, 2015 at 12:20 PM, Dan Kegel <dank at kegel.com> wrote:
>>>>
>>>> Came back to this because it hit me again (14.04 host, 15.10 guest this
>>>> time).
>>>> I actually don't need to be able to write to /proc/sys/kernel/sem
>>>> from inside the container; I just need its limits to be high enough.
>>>>
>>>> $ uname -a
>>>> Linux dank-desktop 3.13.0-66-generic #108-Ubuntu SMP Wed Oct 7
>>>> 15:20:27 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
>>>>
>>>> $ apt-cache policy lxc
>>>> lxc:
>>>>   Installed: 1.1.5-0ubuntu3~ubuntu14.04.1
>>>>
>>>> Looks like at one point, inside was going to inherit from outside:
>>>> http://lists.linuxfoundation.org/pipermail/containers/2014-May/034544.html
>>>> but that doesn't seem to be happening here:
>>>>
>>>> $ cat /proc/sys/kernel/sem
>>>> 250 65536 32 32768
>>>> $ sudo lxc-start -n foo
>>>> $ ssh foo
>>>> $ cat /proc/sys/kernel/sem
>>>> 250 32000 32 128
>>>>
>>>
>>>
>>> Do you have lxcfs installed? At least my installation has high-enough limit
>>> without me having to do anything.
>>>
>>> dev ~ # cat /proc/sys/kernel/sem
>>> 32000   1024000000      500     32000
>>> dev ~ # lxc-attach -n app01 -- cat /proc/sys/kernel/sem
>>> 32000   1024000000      500     32000
>>>
>>> ubuntu 14.04, linux-image-generic-lts-wily 4.2.0.18.13, lxc
>>> 1.1.5-0ubuntu3~ubuntu14.04.1 (from backports), lxcfs
>>> 0.12-0ubuntu5~ubuntu14.04.1~ppa1 (from ppa).
>>>
>>> --
>>> Fajar
>>>
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