[ovs-discuss] OVS-bridges Troubleshooting

[Flavio Leitner]

On Wed, 13 Nov 2019 14:02:33 +0200
aeris <aeris at ytechteam.com> wrote:

> Hello,
> 
> I'm new here, so sorry if i missed something or writing to wrong
> maillist
> 
> A bit of foreword -
> 
> We had an installation of ovs in our cloud environment and faced 
> networking issue with vms at random time, but mostly 3-7 minutes
> after reboot(it just stops answering on every request(typical ICMP)
> during time from a few seconds to a few minutes)
> 
> Our internal network for such kind of requests looks like this -
> 
> Physical-switch-->linux
> bond-->ovs-bridge1-->ovs-bridge2-->ovs-bridge3-->VM
> 
> With ovs-tcpdump i found that there is two-sided communication on
> link to VM and between ovs-bridge1 and linux-bond, but only one-sided 
> communication(only icmp-replies/requests depending on from which side 
> ping was issued) on link between ovs-bridge2 and ovs-bridge3 and no 
> packet on any other interface.
> 
> So, actually, my main question is - what instruments do u use when 
> troubleshooting such issues, which I in turn can use in my 
> implementation. And did you faced similar problems in your
> environments?

I see you're using ovs-tcpdump, but you haven't told us if you're using
DPDK or not. Also, how are the bridges connected to each other? veth?
patch ports? and last, what do you have in the flow table?

One thing that you might find useful is ofproto/trace:
https://developers.redhat.com/blog/2016/10/12/tracing-packets-inside-open-vswitch/

fbl