Generating network traffic from a VM cuts off traffic to host [closed]

asked 2013-08-17 19:43:31 -0500

mnzaki gravatar image

I'm on Ubuntu 13.04, nova 2013.1.2, single node + quantum using the OVS plugin

I'm facing wierd network behaviour which I'm assuming is some form of misconfiguration of OVS. When any internet bound traffic is generated by a VM (for example: ping -c 5 8.8.8.8) it immediately locks down the host machine (no incoming or outgoing packets can make it through any more).

All connections are refused (I've been testing with SSH and VNC). I've tried to trace using iptables and it appears that while in this lockdown packets do not even make it into iptables at all, which is why I'm assuming OVS has something to do with this.

Any ideas on what/how to debug this? What information can I provide?

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Closed for the following reason the question is answered, right answer was accepted by koolhead17
close date 2014-06-05 21:18:02.258654

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answered 2013-08-18 16:55:20 -0500

mnzaki gravatar image

it turns out that you cannot assign the host IP to an openstack router if you are using namespaces. As soon as any traffic is generated from the router the namespace becomes active and any incoming traffic makes its way into it. I've actually tested this by running an ssh server inside the qrouter-XXXX namespace and connecting to it from outside successfully (as long as one of the VMs is pinging the outside world :D)

That took a considerable amount of headscratching because I hadn't dealt with network namespaces before. Next time I should probably read up on the technology before using it blindly.

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Asked: 2013-08-17 19:43:31 -0500

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Last updated: Aug 18 '13