[ovs-discuss] network problem with vxlan

[t22330033]

2014-05-21 0:25 GMT+08:00 Qin, Xiaohong <Xiaohong.Qin at emc.com>:

> Can you session into dhcp namespace to run tcpdump on that tap interface
> to see if the dhcp traffic is been exchanged between dns process and VM?
>
>
tcpdump in the dhcp namespace captures nothing no matter I start an
instance from nova controller or compute node. however the network of VM in
controller node is OK but not OK in compute node.

another finding regarding the manually-created bridge that works for vxlan
is that if I set the fail-mode to secure, it won't send vxlan packet
anymore. I saw the setting on bridges created by neutron are all set to
secure. it that the root cause?


>
>
> Dennis
>
>
>
> *From:* discuss [mailto:discuss-bounces at openvswitch.org] *On Behalf Of *
> t22330033
> *Sent:* Tuesday, May 20, 2014 12:20 AM
> *To:* discuss at openvswitch.org
> *Subject:* Re: [ovs-discuss] network problem with vxlan
>
>
>
> 2014-05-19 23:58 GMT+08:00 Qin, Xiaohong <Xiaohong.Qin at emc.com>:
>
> You have to start with the dhcp problem first in your case. “ip netns” on
> your controller node should list a dhcp name space,
>
>
>
> ip netns
>
> qdhcp-3fc234e5-335f-463d-ba1d-bcf1bdd8f479
>
> qrouter-6df76d30-17fc-4024-8d01-4cfe007ab531
>
>
>
> then session into that dhcp name space,
>
>
>
> sudo ip netns exec qdhcp-3fc234e5-335f-463d-ba1d-bcf1bdd8f479 ifconfig
>
>
>
> it should list a tap interface,
>
>
>
> tapef85f5c3-c5 Link encap:Ethernet  HWaddr fa:16:3e:53:ad:f2
>
>
>
> then check the dnsmasq is launched against that interface,
>
>
>
> dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces
> --interface=tapef85f5c3-c5 -
>
>
>
> everything on the controller behaves the same as you mentioned. and I
> don't have problem on instances running on the controller node. only those
> in compute node have network problem.
>
>
>
>
>
> Also I don’t see ovs physical bridge is been created in your show table.
>
>
>
> do you mean br-ex? the output is from the compute node. I thought there
> are only br-tun and br-int on the compute node.
>
> I also manually created a bridge to compare with those created by
> openstack and I can see vxlan packets being sent out through physical NIC.
> I don't understand what the difference is. here is what I did
>
> # ip tuntap add mode tap vnet0
> # ip link set vnet0 up
> # ovs-vsctl add-br br-vxlan
> # ovs-vsctl add-port br-vxlan vnet0
> # ovs-vsctl add-port br-vxlan tep0 -- set interface tep0 type=vxlan
> options:remote_ip=172.31.0.125
> # qemu-system-x86_64 -m 64 -net nic -net
> tap,ifname=vnet0,script=no,downscript=no -hda cirros-0.3.2-x86_64-disk.img
> -display vnc=:1
>
>
> when I ran ping in the guest VM, I can capture vxlan packets carrying ARP
> requests on eth0 of the host. output of ovs-vsctl show of my manually
> created bridge is as follows
>
>     Bridge br-vxlan
>         Controller "tcp:172.31.0.125:6633"
>         Port "vnet0"
>             Interface "vnet0"
>         Port "tep0"
>             Interface "tep0"
>                 type: vxlan
>                 options: {remote_ip="172.31.0.125"}
>         Port br-vxlan
>             Interface br-vxlan
>                 type: internal
>
> but ovs-ofctl dump-flows shows nothing
>
>     OFPST_FLOW reply (OF1.3) (xid=0x2):
>
>
>
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