[Lxc-users] Issues with mass-starting and bridge

[Leon Waldman]

Hi all,


I'm having a strange issue with the bridge on my lxc host.


First, some background info:
I'm running lxc version 0.75 on a CentOS 6.3 install with the standard 
kernel (2.6.32-279.9.1.el6.i686).
it's running inside a VirtualBox VM.

I created 100 containers and named from 000 to 099. they are all with 
sequential assigned IPs and macaddresses (from 10.0.1.0/8 till 
10.0.1.99/8 | 80:04:C0:AB:00:00 till 80:04:C0:AB:00:63).


When starting them in "mass" with something like:
for i in `range 0 99`; do echo $i; lxc-start -n $i -d; done
after a random number of containers is started the br0 bridge just stops 
to answer for anything. It just freezes (it's easy to note because I'm 
connecting to the host through ssh using the same bridge).

If I put a sleep 5 on the for above, things goes better, but then one or 
two of the containers became a "remote bridge bomb". The bridge stays 
working till a packet arrives to the "bomb" container, and them again 
the entire bridge freezes. This container bomb is also random.

if I remove the problematic container iface from the bridge, it 
unfreezes. If I add it again and send a packet... It freezes again. If I 
stop the container and re-start it... all goes fine and the issue vanish.


 From my point of view, looks like when the virtual iface is created 
during the container start (if under load or with too much concurrent 
starts... I don't know), sometimes something goes wrong with the iface 
and it mess with the entire bridge if this "messy" iface is attached.


Do any one have any input on this (do this happened before? Is there a 
limit for concurrent containers initializations? Is there a kernel 
setting or some config that I could do to solve it)?


In order to achieve what I need in production environment, I will need 
to start and stop containers several times per minute. Do this sound too 
problematic?


If you guys need any additional information, please just let me know.


Thanks in advance

--
*Leon Waldman* <http://leonwaldman.com/>
Senior Linux/UNIX SysAdmin & Consultant.
Back-End & Infrastructure Architect.
View Leon Waldman's profile on LinkedIn 
<http://br.linkedin.com/in/leonwaldman>
<https://twitter.com/lewaldman>
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