[Lxc-users] Error starting a container - could not unmount old rootfs

[Daniel Lezcano]

On 09/22/2010 09:37 PM, Nirmal Guhan wrote:
> On Wed, Sep 22, 2010 at 1:14 AM, Daniel Lezcano<daniel.lezcano at free.fr>  wrote:
>    
>> On 09/22/2010 09:50 AM, Nirmal Guhan wrote:
>>      
>>> On Wed, Sep 22, 2010 at 12:36 AM, Daniel Lezcano<daniel.lezcano at free.fr>
>>>   wrote:
>>>
>>>        
>>>> On 09/22/2010 06:25 AM, Nirmal Guhan wrote:
>>>>
>>>>          
>>>>> Hi,
>>>>>
>>>>> When starting a container, am getting an error as :
>>>>>
>>>>> lxc-start: Device or resource busy - could not unmount old rootfs
>>>>> lxc-start: failed to pivot_root to '/lxc/f12'
>>>>> lxc-start: failed to set rootfs for 'f12connew'
>>>>> lxc-start: failed to setup the container
>>>>>
>>>>> My config is very simple :
>>>>> lxc.utsname = f12connew
>>>>> lxc.rootfs = /lxc/f12
>>>>> lxc.mount = /lxc/f12.fstab
>>>>> lxc.tty = 3
>>>>>
>>>>> Am running 2.6.32.16 kernel. Am able to start the same container while
>>>>> running the same kernel with only one difference - the one that does
>>>>> NOT work has CONFIG_MACVLAN=y but I doubt if that is the issue.
>>>>>
>>>>> Please help.
>>>>>
>>>>>
>>>>>            
>>>> What is the lxc version ?
>>>>
>>>>
>>>>          
>>> lxc version: 0.6.5. Please note that the lxc version is same across
>>> the working and non-working kernels.
>>>
>>>        
>> Mmh, this problem was solved with the 0.7.2 version I think, is it possible
>> to try it ?
>>
>>      
> It works. Thanks. Can I understand the reason for 0.6.5 error? It
> didn't show up always.
>    
I don't remember exactly why but that was happening when the rootfs was 
on the same fs than the host rootfs and this one is mounted with a 
specific option (as far as I remember). The changes made around the 
pivot_root solved the problem. In any case, if the umount of the 
oldrootfs fails, umount --force and umount --detach is done ensuring the 
old rootfs won't be reachable within the container.