[lxc-devel] A question about lxc

[Gui Jianfeng]

Daniel Lezcano wrote:
> Gui Jianfeng wrote:
>> Hi Daniel,
>>
>> I tried lxc and have A question about lxc
>>
>> I successfully built lxc in my box, and i played with
>> it as following.
>>
>> #lxc-create -n foo
>> #lxc-execute -n foo /bin/bash
>> #lxc-ps -n foo
>>
>> Then, I got the following error:
>>
>> cat: /usr/local/var/lib/lxc/foo/nsgroup/tasks: No such file or directory
>> ERROR: List of process IDs must follow -p.
>>
>> I checked the code, IMHO, "/usr/local/var/lib/lxc/foo/nsgroup" should
>> link
>> to the corresponding Cgroup directory. But i can't find out which part
>> of the code takes care of creating Cgroup directory.
>>
>> Would you explain this a bit?
>>   
> 
> Hi Gui,
> 
> lxc does not create the cgroup directory, it is automatically created
> when a namespace is created, this is a feature of the ns_cgroup. It is
> probable you mounted the cgroup without the "ns" option or the feature
> is not enabled in the kernel.
> 
> There is a tool to check the kernel configuration : lxc-checkconfig; it
> should give you some informations about the kernel config.
> You should see something like that:
> 
> --- Namespaces ---
> Namespaces: enabled
> Utsname namespace: enabled
> Ipc namespace: enabled
> Pid namespace: enabled
> User namespace: enabled
> Network namespace: enabled
> Multiple /dev/pts instances: enabled
> 
> --- Control groups ---
> Cgroup: enabled
> Cgroup namespace: enabled
> Cgroup device: enabled
> Cgroup sched: enabled
> Cgroup cpu account: enabled
> Cgroup memory controller: enabled
> Cgroup cpuset: disabled
> 
> --- Misc ---
> Veth pair device: enabled
> Macvlan: enabled

Hi Daniel,

I tried lxc-checkconfig and got the following output with the config 
on 2.6.30.
It seems "ns_cgroup" is already enabled.

Kernel config /proc/config.gz not found, looking in other places...
Found kernel config file /lib/modules/2.6.30/build/.config
--- Namespaces ---
Namespaces: enabled
Utsname namespace: enabled
Ipc namespace: enabled
Pid namespace: enabled
User namespace: enabled
Network namespace: enabled
Multiple /dev/pts instances: disabled

--- Control groups ---
Cgroup: enabled
Cgroup namespace: enabled
Cgroup device: enabled
Cgroup sched: disabled
Cgroup cpu account: enabled
Cgroup memory controller: enabled
Cgroup cpuset: enabled

--- Misc ---
Veth pair device: disabled
Macvlan: disabled


> 
> 
> If you have a custom kernel, you should specify the config location like:
> 
> CONFIG=<path_to_my_config> lxc-checkconfig
> 
> Cheers
>  -- Daniel
> 
> 
> 

-- 
Regards
Gui Jianfeng