[Openstack] 99.5% of packets are disappearing somewhere between the Linux Bridge (brqxxxxzzzz-yy) and the tap (tapxxxxzzzz-yy).

Martinx - ジェームズ thiagocmartinsc at gmail.com
Thu Jul 9 00:41:13 UTC 2015


Guys,

 What can cause packets to just disappear after arriving the bridge
"brqxxxxzzzz-yy" ???

 I'm using "VLAN Provider Networks", Juno on top of Trusty.

 With Neutron ML2 + LinuxBridges, setup "all-in-one".


Where:

 - eth0 is the default - api, etc;
 - eth1 is the "external" - floating ip, etc;
 - eth2 is the physical vlan mapped into ML2;
 - eth3 is another physical vlan mapped into ML2;
 - dummy0 is being used by ML2 for VXLAN.


Explaining:


 * I can see the tagged packets arriving at "eth3", by using "tcpdump -eni
eth2 | grep "vlan 666";

 * I can see the untagged packets arriving at "brq50b13311-fa", by using
"tcpdump -eni brq50b13311-fa";

 * I CAN NOT see the untagged packets arriving at "tap9a546be0-d6", by
using "tcpdump -eni tap9a546be0-d6"!


 "tcpdump -eni tap9a546be0-d6" only shows "alien" packets for this "tap",
like this:

 http://paste.openstack.org/show/356838/ - While what is arriving at
"brq50b13311-fa" looks completely different!

 For example, I can not see the string "Cisco" while running "tcpdump -eni
brq50b13311-fa | grep -i cisco", so, where those packets come from (that
I'm seeing on tap9a546be0-d6 and within its instance - pastebin above) ???


Instance details:
---
...
    <interface type='bridge'>
      <mac address='fa:16:3e:51:16:60'/>
      <source bridge='brq50b13311-fa'/>
      <target dev='tap9a546be0-d6'/>
      <model type='e1000'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
function='0x0'/>
    </interface>
...
---

"brctl show" returns:

---
bridge name            bridge id                   STP enabled
interfaces
....
brq50b13311-fa          8000.ecf4bbd0417b           no
   eth3.666

               tap9a546be0-d6
....
---

"neutron net-show XXX" returns:

 http://paste.openstack.org/show/356845/

-

ML2 configuration contains:

http://paste.openstack.org/show/356860/

-

 Can someone please, tell me, why ~99.5% of the packets are disappearing
out of nothing?

 What is driving me crazy is that, on top of this very same setup
(including e1000 driver), but with different vlan tag, it works!

 I already disabled "rp_filter", ebtables, arptables, iptables, also, all
files under "/proc/sys/net/bridge" have "0"...

 I really appreciate any help! I'm working on this for about 16 hours
straight...

Thanks,
Thiago
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