[Lxc-users] not separeted resources

[Daniel Lezcano]

On 07/13/2010 03:34 AM, Nirmal Guhan wrote:
> On Mon, Jul 12, 2010 at 10:20 AM, Daniel Lezcano<daniel.lezcano at free.fr>  wrote:
>    
>> On 07/12/2010 06:25 PM, atp wrote:
>>      
>>> Nirmal,
>>>
>>>
>>>
>>>        
>>>>>    Per container/per cgroup resource tracking has not been implemented.
>>>>>
>>>>>            
>>>> I think only the *tracking* has not been implemented. It would still
>>>> be possible to configure resources per container using cgroup (cpuset,
>>>> memory etc.) Please confirm.
>>>>
>>>>          
>>>     Yes, resource constraint has been implemented. That is the main
>>> purpose of control groups. The tracking of resource consumption by
>>> control group (as a container has a control group associated with it)
>>> has not been done.
>>>
>>>    Apologies if I was unclear. As always this is based off my
>>> understanding. Please correct me if I'm wrong.
>>>
>>>        
>> The process tracking is the cgroup itself. The different controllers are
>> plugged on this framework, these are known as subsystems and they make use
>> of the cgroup process tracking to assign, account, restrict some resources.
>>
>> The existing subsystems are:
>>
>>   * physical and swap memory : assign an amount of physical memory
>>   * network traffic control : choose network traffic bandwidth and network
>> priority between cgroups
>>   * cpuset : assign cpus (exclusive or not)
>>   * freezer : block all the processes of the container
>>   * cgroup scheduling : a "nice" at the cgroup level
>> * and some accounting informations about the cpus and the memory used
>>
>> The container is tied with a cgroup, so for example if you assign a cgroup
>> scheduling priority higher to another container, this one will be less
>> responsive than the one competing with it.
>>
>> lxc gives a thin abstraction layer between the container and the cgroup, it
>> is up to the user to know the container subsystems in order to assign the
>> right values. That has the advantage to have the lxc code agnostic with the
>> cgroup file system moving interface.
>>
>> The next subsystems and cgroup features are the io nice per cgroup and an
>> event file to notify for example the memory has reached a limit. AFAICS it
>> is for 2.6.35.
>>
>> Unfortunately, the cgroup like the proc fs are not container aware and
>> several times people is complaining they don't understand why when they set
>> the physical memory to 256MB via the cgroup, they don't see the same value
>> in /proc/meminfo ?
>>      
> I read this as the reporting is not virtualized for container but
> limits will still apply per container. For instance I can configure
> 256MB physical memory for container but  it won't show up in meminfo
> or free. The physical limit will still apply. Did I misread?
>    

No, that's correct. The memory will be limited for the container.

Thanks
   -- Daniel