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Why network traffic gets out of control as instance is launched [closed]

asked 2014-01-22 05:35:37 -0500

anemic gravatar image

updated 2014-01-24 06:57:02 -0500

I have followed the standard ubuntu 12.04 installation instructions with GRE networking. I have one controller node and 4 compute nodes. Two network interfaces/node (one public, one private) as per instructions. When I start an instance the network just goes crazy (I'm using 10.0.99. as private net and 10.0.20. as tenant net):

13:58:46.846449 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846453 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846458 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846465 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846471 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846476 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846482 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846489 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846494 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42
13:58:46.846500 IP 10.0.99.5 > 10.0.99.30: GREv0, key=0x4, length 64: ARP, Reply 10.0.20.11 is-at fa:16:3e:e6:b9:b3 (oui Unknown), length 42

It just generates gigabytes of traffic in seconds! The traffic can be ARP or DHCP requests or just pings and somehow the traffic multiplies so that there is a constant flow of packets.

After restarting all services if I get lucky the first instance is working fine without problems but as soon as I create second instance (that gets a different node) the problems begin. When terminating the second instance the traffic will soon stop but then the first instance is not accessible anymore.

I have double checked all the configuration ... (more)

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Closed for the following reason the question is answered, right answer was accepted by anemic
close date 2014-01-27 17:48:16.881898

Comments

Seems like a loop. Check the tunnels are right - 'ovs-vsctl show' - if you previously entered a wrong local_ip, there may be bad tunnel endpoints that will need to be manually deleted from the ovs database.

darragh-oreilly gravatar imagedarragh-oreilly ( 2014-01-22 08:24:45 -0500 )edit

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answered 2014-01-27 16:40:59 -0500

anemic gravatar image

Finally solved it. Somehow from the installation documentation I got the idea to add a port from br-int to internal network just like br-ex is.

So the solution was to remove the port and deconfigure ip from br-int and now it seems to work.

The key to solving this was that the internal vlan communication of the hosts was leaked to the physical network as it should be tunneled with GRE. After scanning through the openflow rules (not recommended reading for anyone) I finally figured out how the networking shoud work. The GRE tunnels are configured with remote_ip=<destination> which will send them with correct interface and need not be connected via openvswich to physical interface.

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Asked: 2014-01-22 05:35:37 -0500

Seen: 602 times

Last updated: Jan 27 '14