[ovs-discuss] Issue when using local_ip with VXLAN tunnels in OVS

[Gregory Rose]

On 11/8/2018 4:16 PM, Gregory Rose wrote:
> On 11/8/2018 3:48 PM, Siva Teja ARETI wrote:
>>
>>
>> Siva,
>>
>>
>>     When you see the error condition with the local_ip option on
>>     vxlan can you provide me the output of
>>     this command?
>>
>>     *# ip -s link show vxlan_sys_4789*
>>     70: vxlan_sys_4789: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65470
>>     qdisc noqueue master ovs-system state UNKNOWN mode DEFAULT group
>>     default qlen 1000
>>         link/ether 0e:9b:58:4a:6e:44 brd ff:ff:ff:ff:ff:ff
>>         RX: bytes  packets  errors  dropped overrun mcast
>>         0          0        0       0       0       0
>>         TX: bytes  packets  errors  dropped carrier collsns
>>         0          0        99      8       99      0
>>
>> Hi Greg,
>>
>> Here is the output.
>>
>> [root at vm1 ~]# ip -s link show vxlan_sys_4789
>> 27: vxlan_sys_4789: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65000 qdisc 
>> noqueue master ovs-system state UNKNOWN mode DEFAULT qlen 1000
>>     link/ether ca:8f:0d:13:08:1f brd ff:ff:ff:ff:ff:ff
>>     RX: bytes  packets  errors  dropped overrun mcast
>>     0          0        0       0       0       0
>>     TX: bytes  packets  errors  dropped carrier collsns
>>     3666796    130957   0       0       0       0
>>
>>  Siva Teja.
>>
>>     It will help me understand which error you're encountering.
>>
>>     Thanks!
>>
>>     - Greg
>>
>
> Well then obviously I still have errors in my own setup.
>
> Back to the drawing board but I think it's a routing issue in my case.
>
> Thanks!
>

Siva,

I've made progress.  I misconfigured my network which led to the errors 
you were seeing.  Now I've got that fixed up and I think I'm reproducing 
the error you are seeing.  When adding the local IP option the packets 
are getting
delivered to the VXLAN port but not getting delivered over to the bridge 
with the local ip address.

I have two machines A and B.  They are bare metal running OVS with kvm 
virtual machines.  Here is the config:

A) IP 10.172.208.214
     Bridge test-vxlan   <-------- ip=10.1.1.3
         Port test-vxlan
             Interface test-vxlan
                 type: internal
         Port "vxlan0"
             Interface "vxlan0"
                 type: vxlan
                 options: {key="100", local_ip="10.1.1.3", 
remote_ip="10.172.208.215"}
         Port "vnet4"
             Interface "vnet4"  <-------- VM 1 with IP 10.1.1.1


B) IP 10.172.208.215
     Bridge test-vxlan <--------- ip=10.1.1.4
         Port "vxlan0"
             Interface "vxlan0"
                 type: vxlan
                 options: {key="100", local_ip="10.1.1.4", 
remote_ip="10.172.208.214"}
         Port "vnet6"
             Interface "vnet6"  <-------- VM 2 with IP 10.1.1.2
         Port test-vxlan
             Interface test-vxlan
                 type: internal

 From VM 2 on machine B I start a ping from 10.1.1.2 -> 10.1.1.1

roseg at ubuntu-1604-base:~$ ping 10.1.1.1
PING 10.1.1.1 (10.1.1.1) 56(84) bytes of data.
 From 10.1.1.2 icmp_seq=1 Destination Host Unreachable
 From 10.1.1.2 icmp_seq=2 Destination Host Unreachable
 From 10.1.1.2 icmp_seq=3 Destination Host Unreachable
 From 10.1.1.2 icmp_seq=4 Destination Host Unreachable

On machine B we can see the vxlan_sys_4789 tx counter increasing:

[root at sc2-hs2-b2515 ~]# ip -s link show vxlan_sys_4789
76: vxlan_sys_4789: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65470 qdisc 
noqueue master ovs-system state UNKNOWN mode DEFAULT group default qlen 1000
     link/ether f2:3a:d4:fd:b3:46 brd ff:ff:ff:ff:ff:ff
     RX: bytes  packets  errors  dropped overrun mcast
     0          0        0       0       0       0
     TX: bytes  packets  errors  dropped carrier collsns
     4200       150      0       8       0       0

On machine A we can see the vxlan_sys_4789 rx counter increasing:

53: vxlan_sys_4789: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65470 qdisc 
noqueue ma
ster ovs-system state UNKNOWN mode DEFAULT group default qlen 1000
     link/ether 06:4b:21:d8:af:8b brd ff:ff:ff:ff:ff:ff
     RX: bytes  packets  errors  dropped overrun mcast
     4200       150      0       0       0       0
     TX: bytes  packets  errors  dropped carrier collsns
     0          0        0       8       0       0

However, even though there is no indication of drops the packets are not 
getting over to the test-vxlan bridge
which has the local 10.1.1.3 ip address:

35: test-vxlan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue 
state UNKNOWN mode DEFAULT group default qlen 1000
     link/ether 86:9b:1f:ae:ba:42 brd ff:ff:ff:ff:ff:ff
     RX: bytes  packets  errors  dropped overrun mcast
     0          0        0       0       0       0
     TX: bytes  packets  errors  dropped carrier collsns
     0          0        0       0       0       0

They're just not seen at all - none of the counters are increasing. When 
I remove the local_ip option from
the vxlan tunnels then the ping between the VMs works as expected which 
you have shown:

roseg at ubuntu-1604-base:~$ ping 10.1.1.1
PING 10.1.1.1 (10.1.1.1) 56(84) bytes of data.
64 bytes from 10.1.1.1: icmp_seq=1 ttl=64 time=2.04 ms
64 bytes from 10.1.1.1: icmp_seq=2 ttl=64 time=0.366 ms
64 bytes from 10.1.1.1: icmp_seq=3 ttl=64 time=0.332 ms
64 bytes from 10.1.1.1: icmp_seq=4 ttl=64 time=0.335 ms
64 bytes from 10.1.1.1: icmp_seq=5 ttl=64 time=0.367 ms
64 bytes from 10.1.1.1: icmp_seq=6 ttl=64 time=0.319 ms
64 bytes from 10.1.1.1: icmp_seq=7 ttl=64 time=0.272 ms
.
.
.

So now that I have a reproduction I'm debugging why they're not getting 
delivered...

I'll continue to update as the investigation continues.

- Greg

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