Re: [ovs-discuss] Traffic got stuck in a port

[Valentine Sinitsyn]

Hi,

On 14.10.2016 22:22, D3c3 Balus wrote:

Can you take snapshots of flows in the kernel at different moments in time 
(when everything is OK and it is not) using the dpctl utility (ovs-dpctl) ?
Thanks for the quick reply. I tried this (sorry for not mentioning it 
earlier). When traffic flow resumes, OVS install many flows naturally, 
so it's hard to compare "before" and "after" states.


Is there anything specific in datapath flows we should look for?

Valentine





On Oct 14, 2016, at 12:11 PM, Valentine Sinitsyn  
wrote:

Hi everyone,

We are observing strange OVS behavior in some of our setups.

Sometimes, the traffic just stops flowing through veth or tap interfaces 
plugged into OVS bridge.

ovs-appctl ofproto/trace for sample packet show that OVS will output it to the 
correct port, and we see real traffic in a mirror port we add to OVS.

This persists until one re-initializes the interface with ip link set down && 
ip link set up. Then the traffic flow restores. Nothing changes in OF flows as per 
ovs-ofctl dump-flows, except cookie value, which I presume means OVS re-installed the 
flows. The OVS database remains the same as well, except stats.

How can we debug this? I'm giving a high-level overview without any details as 
I'm not seeking for the solution, just a way to find one. I'm okay with OVS 
internals and diving into the kernel.

Many thanks,
Valentine Sinitsyn
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Re: [ovs-discuss] Traffic got stuck in a port

[D3c3 Balus]

Can you take snapshots of flows in the kernel at different moments in time 
(when everything is OK and it is not) using the dpctl utility (ovs-dpctl) ?


> On Oct 14, 2016, at 12:11 PM, Valentine Sinitsyn 
>  wrote:
> 
> Hi everyone,
> 
> We are observing strange OVS behavior in some of our setups.
> 
> Sometimes, the traffic just stops flowing through veth or tap interfaces 
> plugged into OVS bridge.
> 
> ovs-appctl ofproto/trace for sample packet show that OVS will output it to 
> the correct port, and we see real traffic in a mirror port we add to OVS.
> 
> This persists until one re-initializes the interface with ip link set down && 
> ip link set up. Then the traffic flow restores. Nothing changes in OF flows 
> as per ovs-ofctl dump-flows, except cookie value, which I presume means OVS 
> re-installed the flows. The OVS database remains the same as well, except 
> stats.
> 
> How can we debug this? I'm giving a high-level overview without any details 
> as I'm not seeking for the solution, just a way to find one. I'm okay with 
> OVS internals and diving into the kernel.
> 
> Many thanks,
> Valentine Sinitsyn
> ___
> discuss mailing list
> discuss@openvswitch.org
> http://openvswitch.org/mailman/listinfo/discuss

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