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(Mitaka, SR-IOV) Possible to mix Flat and VXLAN nets on same VM?

asked 2017-05-10 11:09:33 -0500

tomas gravatar image

We have a setup where we have two nodes directly connected to each other via high-speed NICs, and then a normal connection to the switch. We have SR-IOV configured for the fast NICs.

What I want is to use a flat network for SR-IOV, and then a VXLAN configuration for the "management" and internet connection using the normal NIC that's connected to the switch. So right now there are two networks: flat_1 and admin_internal_net.

I've created a VM with an IP from an SR-IOV port (--nic port-id=...) and an IP from admin_internal_net (--nic net-id=...) and I can connect to the VM through the flat network, but if I add a floating ip and try to ping that it does not work and the VM does not have an internet connection. Creating a VM with only an IP from admin_internal_net can be assigned a floating ip as usual.

So my question is, should this be possible, and if it is, is there something additional that needs to be configured somewhere for these two network types to be mixed?

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Yes it is possible. How did you configure the VXLAN? Instructions for a typical set up are at

Bernd Bausch gravatar imageBernd Bausch ( 2017-05-10 12:39:48 -0500 )edit

We are using Fuel for our deployment so that takes care of the VXLAN configuration for the most part. But as it turned out, it was a silly problem where I just had to remove the gateway from the flat subnets; without the GW everything works like a charm.

tomas gravatar imagetomas ( 2017-05-11 02:17:11 -0500 )edit

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answered 2017-05-11 02:20:32 -0500

tomas gravatar image

Answering my own question but; yes it is possible and the problem was the we had gateways configured for the flat subnets. If the gateways are removed then everything works as it should.

So essentially the network configuration ended up as: - 1 "Management" VXLAN network - 1 flat network representing the fast NIC, with DHCP disabled and gateway disabled

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Asked: 2017-05-10 11:09:33 -0500

Seen: 276 times

Last updated: May 11 '17