[ovs-dev] Issue with OVS lacp-fallback-ab option

Arun Navasivasakthivelsamy arunkum.navasiv at nutanix.com
Mon Oct 8 20:57:06 UTC 2018


Thanks Ben. Let me try it out this week and report back.

On 10/8/18, 1:15 PM, "Ben Pfaff" <blp at ovn.org> wrote:

>I think I see a problem in the implementation of bonding when
>recirculation is available.  Are you able to try out a patch?  If so,
>try the following.  It is not a good way to solve the issue, but it
>should illustrate whether recirculation is the problem.
>
>diff --git a/ofproto/bond.c b/ofproto/bond.c
>index f87cdba7908f..bb6a80411de5 100644
>--- a/ofproto/bond.c
>+++ b/ofproto/bond.c
>@@ -927,7 +928,7 @@ bond_recirculation_account(struct bond *bond)
> static bool
> bond_may_recirc(const struct bond *bond)
> {
>-    return bond->balance == BM_TCP && bond->recirc_id;
>+    return bond->balance == BM_TCP && bond->recirc_id && false;
> }
> 
> static void
>
>
>On Fri, Oct 05, 2018 at 04:45:21AM +0000, Arun Navasivasakthivelsamy
>wrote:
>> Also, ofproto/trace is suggesting that the packet will be hashed to a
>>slave (instead of just to the active port) with lacp-fallback-ab option.
>> 
>> This is with active-backup bond mode:
>> 
>> 
>> [root at frankfurter02-4 ~]# ovs-appctl ofproto/trace br0
>>in_port=6,dl_dst=28:99:3a:08:7a:cf
>> 
>> Bridge: br0
>> 
>> Flow: 
>>in_port=6,vlan_tci=0x0000,dl_src=00:00:00:00:00:00,dl_dst=28:99:3a:08:7a:
>>cf,dl_type=0x0000
>> 
>> 
>> Rule: table=0 cookie=0 priority=0
>> 
>> OpenFlow actions=NORMAL
>> 
>> forwarding to learned port
>> 
>> 
>> Final flow: unchanged
>> 
>> Megaflow: 
>>recirc_id=0,in_port=6,vlan_tci=0x0000/0x1fff,dl_src=00:00:00:00:00:00,dl_
>>dst=28:99:3a:08:7a:cf,dl_type=0x0000
>> 
>> Datapath actions: 5
>> 
>> 
>> This is with balance-tcp with lacp-fallback-ab mode (LACP is not
>>negotiated):
>> 
>> 
>> [root at frankfurter02-4 ~]# ovs-appctl ofproto/trace br0
>>in_port=6,dl_dst=28:99:3a:08:7a:cf
>> 
>> Bridge: br0
>> 
>> Flow: 
>>in_port=6,vlan_tci=0x0000,dl_src=00:00:00:00:00:00,dl_dst=28:99:3a:08:7a:
>>cf,dl_type=0x0000
>> 
>> 
>> Rule: table=0 cookie=0 priority=0
>> 
>> OpenFlow actions=NORMAL
>> 
>> forwarding to learned port
>> 
>> 
>> Final flow: unchanged
>> 
>> Megaflow: 
>>recirc_id=0,in_port=6,vlan_tci=0x0000/0x1fff,dl_src=00:00:00:00:00:00,dl_
>>dst=28:99:3a:08:7a:cf,dl_type=0x0000
>> 
>> Datapath actions: hash(hash_l4(0)),recirc(0x1)
>> 
>> From: Arunkumar Navasiva
>><arunkum.navasiv at nutanix.com<mailto:arunkum.navasiv at nutanix.com>>
>> Date: Thursday, October 4, 2018 at 4:18 PM
>> To: "ovs-dev at openvswitch.org<mailto:ovs-dev at openvswitch.org>"
>><ovs-dev at openvswitch.org<mailto:ovs-dev at openvswitch.org>>
>> Subject: Issue with OVS lacp-fallback-ab option
>> 
>> Hello folks,
>> 
>> We¹re seeing an issue with lacp-fallback-ab option on ovs 2.5/2.6/2.8.
>>It looks like when LACP is not enabled on the TOR switch ports, OVS on
>>the centos server is not falling back cleanly to active-backup, and
>>continues to send some portions of the traffic through the backup
>>interface (we¹ve seen this occur with various TOR vendor switches).
>>Please see the attached screenshot which shows that some traffic still
>>hashes to backup interface. We looked at the TOR forwarding table, and
>>MAC addresses of VMs running on this server flaps between the two
>>corresponding TOR switch ports of the bond . I¹m still in the early
>>stages of debugging this, but wanted to reach out to you to see if this
>>is already a known issue? If not, any help on how to debug this further
>>will be helpful.
>> 
>> 
>> Thanks
>> -Arun
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