why the pid namespace is not compiled in the kernel ?

[Tim Gardner]

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
> 
> 
> 
> 
> 
> 

Enabled.

http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-jaunty.git;a=commit;h=c0399d5596fb3db7f685bd59ab0c93b3612f3ee9
-- 
Tim Gardner tim.gardner at canonical.com