why the pid namespace is not compiled in the kernel ?

[Daniel Lezcano]

Tim Gardner wrote:
> Daniel Lezcano wrote:
>   
>> Tim Gardner wrote:
>>     
>>> Daniel Lezcano wrote:
>>>  
>>>       
>>>> Tim Gardner wrote:
>>>>    
>>>>         
>>>>> Daniel Lezcano wrote:
>>>>>  
>>>>>      
>>>>>           
>>>>>> Daniel Lezcano wrote:
>>>>>>           
>>>>>>             
>>>>>>> Hi,
>>>>>>>
>>>>>>> I hope it is the right mailing list to ask  :)
>>>>>>>
>>>>>>> I tried the latest kernel version from "intrepid" and it looks like
>>>>>>> the namespaces are compiled in except the pid namespace (according
>>>>>>> the config file stored in /boot).
>>>>>>> Is there any particular reason ?
>>>>>>>
>>>>>>> Thanks.
>>>>>>>  -- Daniel
>>>>>>>
>>>>>>> ps: I recently subscribed to this mailing list, sorry if this
>>>>>>> question was already asked ...
>>>>>>>                   
>>>>>>>               
>>>>>> did I ask to the right mailing list ?
>>>>>>
>>>>>>             
>>>>>>             
>>>>> Though there are a few features included in the config that depend on
>>>>> EXPERIMENTAL, CONFIG_PID_NS is not deemed sufficiently interesting to
>>>>> mess with.
>>>>>         
>>>>>           
>>>> Ah, I see, like the network namespace, it is experimental, that makes
>>>> sense.
>>>> We will have to wait a litlle before having a full featured container in
>>>> Ubuntu :)
>>>>
>>>> Thanks.
>>>>  -- Daniel
>>>>
>>>>     
>>>>         
>>> I'm not totally opposed, but you'll need to convince me with use cases
>>> and some stability analysis.
>>>   
>>>       
>> The namespaces with the control group provides the ability to create a
>> virtual private server.
>> You can launch an application like sshd or apache with its own private
>> resources, that allows to make several instances of the same server on
>> the same host without conflicts. You can launch several operating
>> systems (eg. a debian) on the same host.
>> This is different from the virtual machine because the kernel is shared
>> and it is up to it to handle the system resources per group of processes.
>> The advantage of this approach is the scalability and the very low
>> overhead of the virtualization.
>>
>> There are two projects implementing the container feature, the libvirt
>> and the liblxc.
>>
>> The pid namespace is enabled since fedora 9 and opensuse 11, and I
>> didn't fall into any problem while using the liblxc, I guess we can
>> consider it stable.
>> The network namespace is mutually exclusive with sysfs until 2.6.29,  I
>> spotted 2 bugs in the netwok namespace and I am fixing them right now,
>> one is leading to a kernel panic (fixed) and the last one just fails
>> gracefully, sometimes, to create a network namespace when trying to
>> instantiate a new network namespace in a infinite loop.
>>
>> AFAICS, nobody complained about the namespaces being enabled in these
>> different distros.
>>
>> The namespaces tests are included in the ltp test suite, so IMHO, it is
>> reasonable to say they are stable.
>> In any case, "experimental" is a scary word and I understand why the
>> feature would not be enabled for a stable kernel version :)
>> If the features are missing I can live with a custom kernel until
>> everything is enabled.
>>
>> FYI, I added the lxc.7 man page to this email, I hope that can give some
>> clues of what we can do with the namespaces and the cgroup :)
>>
>> Thanks.
>>  -- Daniel
>>     
Hi,

The return ... :)

I was wondering if the network namespace will be enabled for the 2.6.29 
kernel version too ?
The network namespace does not add any overhead neither extra memory 
consumption when it is enabled in the kernel.

Thanks
   -- Daniel