Open Stack

This might be a bit silly, but have you checked your routes?

Regards,
Victor Palma


On Aug 23, 2013, at 6:28 PM, Geraint Jones <geraint at koding.com> wrote:

> Hi
> 
> I have an interesting use case for quantum networking
> 
> This is the example :
> 
> Server A eth0 10.1.1.1 (http proxy) 
> Server B eth0 10.1.1.2 (runs LXC VM's) 
> Server B lxc-br 10.1.2.0/24 (the LXC's get addresses here)
> 
> Server A and B run OSPF so server A knows 10.1.2.0/24 is behind 10.1.1.2. (We have more than just A and B hence the useage of OSPF)
> 
> If I ping 10.1.2.1 from Server A it fails. 
> If I ping Server A from a VM with IP 10.1.2.1 then it works, however looking at the tcpdump the source of the VM's ICMP is rewritten to Server B's eth0 address.
> 
> Digging a bit deeper I see this on Server B when pinging from Server A to an LXC
> 
> tcpdump -i eth0 host 10.1.2.1
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
> 13:49:52.850764 IP 10.1.1.1 > 10.1.2.1: ICMP echo request, id 25672, seq 387, length 64
> 13:49:52.850878 IP 10.1.2.1 > 10.1.1.1: ICMP echo reply, id 25672, seq 387, length 64
> 13:49:53.850600 IP 10.1.1.1 > 10.1.2.1: ICMP echo request, id 25672, seq 388, length 64
> 13:49:53.850710 IP 10.1.2.1 > 10.1.1.1: ICMP echo reply, id 25672, seq 388, length 64
> 
> And this is what I see on Server A
> 
> tcpdump -i eth0 icmp
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
> 13:53:41.852613 IP 10.1.1.1 > 10.1.2.1: ICMP echo request, id 25672, seq 616, length 64
> 13:53:42.852603 IP 10.1.1.1 > 10.1.2.1: ICMP echo request, id 25672, seq 617, length 64
> 
> So the ICMP is getting to the VM without being rewritten, and the reply is being sent to Server A but something is dropping it in transit - I suspect its Open vSwitch GRE...
> 
> If anyone can shed any light on this and if there is something I can do to stop this that would be awesome, We have been doing the on AWS however we have had to create GRE tunnels there inside the instances to make it work, We would love it if we didnt have to do that :)
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