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

Siva Teja ARETI siva_teja.areti at nuagenetworks.net
Tue Nov 20 02:30:35 UTC 2018


On Mon, Nov 19, 2018 at 7:17 PM Gregory Rose <gvrose8192 at gmail.com> wrote:

>
> Hi Siva,
>
> One more request  - I need to see the underlying network configuration
> of the hypervisor running the two VMs.
> Are both VMs on the same machine?  If so then just the network
> configuration of the base machine
> running the VMs, otherwise the network configuration of each base
> machine running their perspective
> VM.
>
> This is turning into quite the investigation and I apologize that it is
> taking so long.  Please bear with me
> if you can and we'll see if we can't get this problem solved.  I've seen
> some puzzling bugs before and
> this one is turning out to be one of the best.  Or worst.... depends on
> your outlook.  :)
>
> Thanks for all your help so far!
>
> - Greg
>

Hi Greg,

Both the VMs run on same hypervisor in my setup. Created VMs and virtual
networks using virsh commands. Virsh XMLs for networks look like below

[user at hyp1 ] virsh net-dumpxml route1
<network connections='2'>
  <name>route1</name>
  <uuid>2c935aaf-ebde-5b76-a903-4fccb115ff75</uuid>
  <forward mode='route'/>
  <bridge name='testbr1' stp='on' delay='0'/>
  <mac address='42:54:00:84:4e:04'/>
  <ip address='20.20.0.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='20.20.0.2' end='20.20.0.254'/>
    </dhcp>
  </ip>
</network>

[user at hyp1 ]  network virsh net-dumpxml route2
<network connections='2'>
  <name>route2</name>
  <uuid>2c935baf-ebde-5b76-a903-4fccb115ff75</uuid>
  <forward mode='route'/>
  <bridge name='testbr2' stp='on' delay='0'/>
  <mac address='42:54:10:84:4e:04'/>
  <ip address='30.30.0.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='30.30.0.2' end='30.30.0.254'/>
    </dhcp>
  </ip>
</network>

Each VM is connected to both the networks.

Some network configuration of the hypervisor.

[user at hyp-1] ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group
default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1400 qdisc pfifo_fast
state UP group default qlen 1000
    link/ether <mac> brd ff:ff:ff:ff:ff:ff
    inet A.B.C.D/24 brd X.Y.Z.W scope global dynamic enp5s0
       valid_lft 318349sec preferred_lft 318349sec
3: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state
UP group default qlen 1000
    link/ether fe:54:00:0a:d3:70 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN
group default qlen 1000
    link/ether 52:54:00:94:4e:04 brd ff:ff:ff:ff:ff:ff
11: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state
UP group default
    link/ether 02:42:89:28:db:a5 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:89ff:fe28:dba5/64 scope link
       valid_lft forever preferred_lft forever
96: vboxnet0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast
state DOWN group default qlen 1000
    link/ether 0a:00:27:00:00:00 brd ff:ff:ff:ff:ff:ff
    inet 192.168.99.1/24 brd 192.168.99.255 scope global vboxnet0
       valid_lft forever preferred_lft forever
    inet6 fe80::800:27ff:fe00:0/64 scope link
       valid_lft forever preferred_lft forever
193: testbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue
state DOWN group default qlen 1000
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
    inet 10.10.0.1/24 brd 10.10.0.255 scope global testbr0
       valid_lft forever preferred_lft forever
194: testbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state
DOWN group default qlen 1000
    link/ether 42:54:00:94:4e:04 brd ff:ff:ff:ff:ff:ff
227: testbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UP group default qlen 1000
    link/ether fe:54:00:05:93:7c brd ff:ff:ff:ff:ff:ff
    inet 20.20.0.1/24 brd 20.20.0.255 scope global testbr1
       valid_lft forever preferred_lft forever
228: testbr1-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state
DOWN group default qlen 1000
    link/ether 42:54:00:84:4e:04 brd ff:ff:ff:ff:ff:ff
229: testbr2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UP group default qlen 1000
    link/ether fe:54:00:79:ef:92 brd ff:ff:ff:ff:ff:ff
    inet 30.30.0.1/24 brd 30.30.0.255 scope global testbr2
       valid_lft forever preferred_lft forever
230: testbr2-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state
DOWN group default qlen 1000
    link/ether 42:54:10:84:4e:04 brd ff:ff:ff:ff:ff:ff
231: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
master virbr0 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:0a:d3:70 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fe0a:d370/64 scope link
       valid_lft forever preferred_lft forever
232: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
master testbr2 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:b8:05:be brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:feb8:5be/64 scope link
       valid_lft forever preferred_lft forever
233: vnet2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
master testbr1 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:f0:64:37 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fef0:6437/64 scope link
       valid_lft forever preferred_lft forever
234: vnet3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
master virbr0 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:56:cb:89 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fe56:cb89/64 scope link
       valid_lft forever preferred_lft forever
235: vnet4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
master testbr2 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:79:ef:92 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fe79:ef92/64 scope link
       valid_lft forever preferred_lft forever
236: vnet5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
master testbr1 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:05:93:7c brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fe05:937c/64 scope link
       valid_lft forever preferred_lft forever
[user at hyp-1] ip route
default via A.B.C.D dev enp5s0  proto static  metric 100
10.10.0.0/24 dev testbr0  proto kernel  scope link  src 10.10.0.1 linkdown
20.20.0.0/24 dev testbr1  proto kernel  scope link  src 20.20.0.1
30.30.0.0/24 dev testbr2  proto kernel  scope link  src 30.30.0.1
A.B.C.D via P.Q.R.S dev enp5s0  proto dhcp  metric 100
X.Y.Z.W dev enp5s0  proto kernel  scope link  src A.B.C.D  metric 100
172.17.0.0/16 dev docker0  proto kernel  scope link  src 172.17.0.1
192.168.99.0/24 dev vboxnet0  proto kernel  scope link  src 192.168.99.1
linkdown
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1

I am not completely sure what you meant by network configuration. Kindly
let me know if you are looking for something more specific.

There is one strange behavior that I observed on the VMs. I am able to ping
across networks if I use IP address but it does not work if I use interface
name directly.

[root at vm2 ~]# ip addr  show eth1
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state
UP qlen 1000
    link/ether 52:54:00:79:ef:92 brd ff:ff:ff:ff:ff:ff
    inet 30.30.0.193/24 brd 30.30.0.255 scope global dynamic eth1
       valid_lft 2728sec preferred_lft 2728sec
    inet6 fe80::5054:ff:fe79:ef92/64 scope link
       valid_lft forever preferred_lft forever
[root at vm2 ~]# ping 20.20.0.183 -I eth1
PING 20.20.0.183 (20.20.0.183) from 30.30.0.193 eth1: 56(84) bytes of data.
^C
--- 20.20.0.183 ping statistics ---
7 packets transmitted, 0 received, 100% packet loss, time 6000ms

[root at vm2 ~]# ping 20.20.0.183 -I 30.30.0.193
PING 20.20.0.183 (20.20.0.183) from 30.30.0.193 : 56(84) bytes of data.
64 bytes from 20.20.0.183: icmp_seq=1 ttl=64 time=0.766 ms
64 bytes from 20.20.0.183: icmp_seq=2 ttl=64 time=0.561 ms
64 bytes from 20.20.0.183: icmp_seq=3 ttl=64 time=0.605 ms
64 bytes from 20.20.0.183: icmp_seq=4 ttl=64 time=0.537 ms
64 bytes from 20.20.0.183: icmp_seq=5 ttl=64 time=0.607 ms
64 bytes from 20.20.0.183: icmp_seq=6 ttl=64 time=0.618 ms
64 bytes from 20.20.0.183: icmp_seq=7 ttl=64 time=0.624 ms
^C
--- 20.20.0.183 ping statistics ---
7 packets transmitted, 7 received, 0% packet loss, time 6000ms
rtt min/avg/max/mdev = 0.537/0.616/0.766/0.075 ms
[root at vm2 ~]#

I don't the reason behind this and I will need to understand this when I
get some time. Just letting you know if it might make any difference in
your setup.

Siva Teja.
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