[Lxc-users] seeing a network pause when starting and stopping LXCs - how do I stop this?

[Daniel Lezcano]

On 12/12/2011 04:48 AM, Derek Simkowiak wrote:
> When there are only one bridge on the system or the bridges are not
> connected together, this option is pointless and we can set the delay to
> '0'. That makes the port to be enabled instantaneously, hence the
> container can access the network immediately after the start.
>
>
>      As previously posted, this is not what causes the network "freeze" 
> with LXC.
>
>      The problem is not related to the setfd option.  It is caused by 
> the bridge acquired a new MAC address.  Libvirt already has a fix for 
> this, and there is a patch in the works for the LXC tools.
>
>      See my post about this four days ago at this URL, which includes a 
> link to the patch and a link to a possible workaround:
>
> http://osdir.com/ml/lxc-chroot-linux-containers/2011-12/msg00029.html

Yes, I was aware of that. I was just explaining why disabling setfd was
useful.
I have queued the patch to set an higher mac address.

Thanks
  -- Daniel

> Thanks,
> Derek
>
> On 12/11/2011 02:21 PM, Daniel Lezcano wrote:
>> On 12/08/2011 09:25 AM, Ulli Horlacher wrote:
>>> On Thu 2011-12-08 (07:39), Daniel Lezcano wrote:
>>>> On 12/08/2011 12:38 AM, Joseph Heck wrote:
>>>>
>>>>> I've been seeing a pause in the whole networking stack when starting
>>>>> and stopping LXC - it seems to be somewhat intermittent, but happens
>>>>> reasonably consistently the first time I start up the LXC.
>>>>>
>>>>> I'm using ubuntu 11.10, which is using LXC 0.7.5
>>>>>
>>>>> I'm starting the container with lxc-start -d -n $CONTAINERNAME
>>>> That could be the bridge configuration. Did you do 'brctl setfd br0 0' ?
>>> I have this in my /etc/network/interfaces (Ubuntu 10.04):
>>>
>>> auto br0
>>>          iface br0 inet static
>>>          address 129.69.1.227
>>>          netmask 255.255.255.0
>>>          gateway 129.69.1.254
>>>          bridge_ports eth0
>>>          bridge_stp off
>>>          bridge_maxwait 5
>>>          post-up /usr/sbin/brctl setfd br0 0
>>>
>>>
>>> I have never noticed a network freeze and I really often start/stop LXC
>>> containers. Does this "brctl setfd br0 0" prevent the freeze? I do not
>>> remember why I have added it :-}
>> The setfd delay is used when there are several bridge setup on the
>> system to detect if the packet are looping across the bridges and to
>> learn the spawning tree control. AFAIR, a packet is transmitted on the
>> new port and the bridge waits for<delay>  to see if the packet goes out
>> of the bridge and came back from another port. During this delay, the
>> port is not enabled.
>>
>> When there are only one bridge on the system or the bridges are not
>> connected together, this option is pointless and we can set the delay to
>> '0'. That makes the port to be enabled instantaneously, hence the
>> container can access the network immediately after the start.
>>
>>
>>
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> ------------------------------------------------------------------------------
> Learn Windows Azure Live!  Tuesday, Dec 13, 2011
> Microsoft is holding a special Learn Windows Azure training event for 
> developers. It will provide a great way to learn Windows Azure and what it 
> provides. You can attend the event by watching it streamed LIVE online.  
> Learn more at http://p.sf.net/sfu/ms-windowsazure
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