[ovs-discuss] OVS-bridges Troubleshooting

aeris aeris at ytechteam.com
Thu Nov 14 12:38:03 UTC 2019


about flows - maybe this output would be better -

  br-int(ovs-bridge3)
  cookie=0x9f5f4658300163fb, duration=255211.898s, table=71, 
n_packets=221, n_bytes=9282, 
priority=95,arp,reg5=0x46,in_port="tapafe5cc97-46",dl_src=b2:ac:73:a2:4e:20,arp_spa=*.*.*.16 
actions=resubmit(,94)
  cookie=0x9f5f4658300163fb, duration=255211.898s, table=71, 
n_packets=68274, n_bytes=6379501, 
priority=65,ip,reg5=0x46,in_port="tapafe5cc97-46",dl_src=b2:ac:73:a2:4e:20,nw_src=*.*.*.16 
actions=ct(table=72,zone=NXM_NX_REG6[0..15])
  br-ex(ovs-bridge2)
  cookie=0x539c250217577d59, duration=3197928.791s, table=0, 
n_packets=717237943, n_bytes=120156920973, 
priority=4,in_port="phy-br-ex",dl_vlan=3 actions=strip_vlan,NORMAL
  cookie=0x539c250217577d59, duration=3197935.391s, table=0, 
n_packets=1919206, n_bytes=278077793, priority=2,in_port="phy-br-ex" 
actions=drop
  cookie=0x539c250217577d59, duration=3197935.397s, table=0, 
n_packets=850526618, n_bytes=408960488324, priority=0 actions=NORMAL
  br-phy(ovs-bridge1)
  cookie=0x0, duration=3599826.112s, table=0, n_packets=1574126232, 
n_bytes=530825513146, priority=0 actions=NORMAL

On 11/14/2019 11:58 AM, aeris wrote:
> We aren't using DPDK now, ports seems to be patch ports as of some 
> output of ovs-*ctl commands
>
> About flow table what I can show ? To be more exact - which out of 300 
> flows you're interested in (as output of ovs-vsctl dump-flows)?
>
> If it is about something about "problematic" VM then -
> recirc_id(0),in_port(18),ct_state(-trk),eth(src=b2:ac:73:a2:4e:20),eth_type(0x0800),ipv4(src=*.*.*.16,proto=6,frag=no), 
> packets:46, bytes:3404, used:0.573s, flags:PR., 
> actions:ct(zone=3),recirc(0xaf01f)
>
> recirc_id(0xaf01f),in_port(18),ct_state(-new+est-rel+rpl-inv+trk),ct_zone(0x3),ct_mark(0),eth(src=b2:ac:73:a2:4e:20,dst=64:c3:d6:bb:05:4a),eth_type(0x0800),ipv4(frag=no), 
> packets:46, bytes:3404, used:0.570s, flags:PR., 
> actions:push_vlan(vid=500,pcp=0),11
>
>
> Also I've tried to use "ovs-appctl ofproto/trace <bridge-name>" and 
> none of my bridges accepted as an argument(Previously listed them via 
> "ovs-appctl ofproto/list")
>
> stderr told me : "ovs-appctl: ovs-vswitchd: server returned an error"
>
>
> On 11/13/2019 3:29 PM, Flavio Leitner wrote:
>> 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
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