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

Derek Simkowiak derek at simkowiak.net
Mon Dec 12 03:48:34 UTC 2011


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


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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