[Users] Delay in venet arp response

[Kir Kolyshkin]

On 07/25/2014 02:23 AM, Yefim Gasel wrote:
> Hello,
>
> For a long time we're having an issue with venet-connected containers — delay in arp response from the host machine:
> 11:10:29.319394 ARP, Request who-has 192.168.1.105 tell 192.168.1.1, length 46
> 11:10:29.539115 ARP, Reply 192.168.1.105 is-at 00:25:90:d9:d5:c7, length 28
>
>  - it takes approximately 220ms (the time is different on every request) for the host to respond with container's mac address.
>
> We're having this problem on different hardware running different kernel versions (all of them are 2.6.32 based) and different switches (HP or Juniper).
> veth doesn't have this problem, CT0's mac address is sent without delay too.
>
> Host has several network interfaces, but only one is up. We don't mix veth and venet on a single machine.
>
> Any ideas why is it happening?

I just did some testing, it's about the same for me, so this is not
something particular about your setup.

My wild guess would be that APR reply for CT venet address takes time
because the kernel
needs to consult its routing table, whereas for the host IP it can reply
instantly. Still 200 ms
is a bit too high.

Feel free to file a bug to bugzilla.openvz.org about it.

Kir.