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Howto use VLAN tagged external networks?

asked 2014-12-15 10:22:11 -0600

Anorak gravatar image

updated 2014-12-16 13:40:46 -0600

darragh-oreilly gravatar image


I have managed to install openstack with the neutron setup as described in the guide and everything is working fine. However, I have failed to find any configuration relating to my scenario which is described as below;

Current Scenario

Controller: 1st NIC (management)

Compute : 1st NIC (management), 2nd NIC (GRE Tunnel)

Neutron : 1st NIC (management), 2nd NIC (GRE Tunnel), 3rd NIC (External Network)

Now, What I would like is to use VLAN-tagged (external network) subnets as the VLAN tagging is done on the switch in the above scenario but I would like to set our switch's port as trunk and do the VLAN tagging on an openstack level for multiple subnets. Any help will be appreciated!

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The Rackspace multi-part networking blog post that Oreilly pointed to, is probably the best source available. It is very helpful if you find the neutron vocabulary confusing and you have a networking background.

Zollner Robert gravatar imageZollner Robert ( 2014-12-16 18:23:59 -0600 )edit

Thanks both! I will read the blog and see if I can come up with a solution.

Anorak gravatar imageAnorak ( 2014-12-17 06:34:29 -0600 )edit

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answered 2014-12-16 18:35:47 -0600

jbajin gravatar image

So the easiest thing to do is to just create VLAN based interfaces from that third NIC. It would be something like eth3.660, eth3.670, eth3.800 or whatever the other VLAN ID's that you decided to use. That makes things a lot easier when you are looking to troubleshoot via tcpdump or another tool. That lets you set-up you switch port as a trunk port.

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Assuming my knowledge is correct, "br-ex" can be mapped to only one It cannot be mapped to multiple eth3.yyy or eth3.zzz. Correct?

Anorak gravatar imageAnorak ( 2014-12-17 06:36:28 -0600 )edit

You could map bridges to other interfaces, but for what you are trying to do, no it will not work. br-ex is the bridge that your external interface attaches too. Your system has no idea what to do with those additional interfaces and would just confuse flow.

jbajin gravatar imagejbajin ( 2014-12-21 23:39:51 -0600 )edit

Hi, I am facing the same problem with allowing multiple networks(VLAN's) through br-ex mapped to physical switch trunk port. How should i configure phy int eth3 mapped to br-ex to allow multiple subnets from the physical switch trunk link? I would really appreciate your help with this. Thanks!

beinghuman gravatar imagebeinghuman ( 2015-05-08 20:37:38 -0600 )edit

Would love also to do the same. I've been trying for the whole week with a lot of google/examples, nothing worked. Clearly I most be doing something wrong, but can't find where. My br-ex as a physical nic attached to it. I would like to use the same br-ex for other vlans, I'm not sure where to l

flovax gravatar imageflovax ( 2016-05-13 10:41:43 -0600 )edit

I think I just got it (two hours after posting...): network_vlan_ranges = physnet1:2:2,physnet1:24:24,physnet1:100:100,physnet1:200:200

I had to put the same physnet1 everywhere. The, in /etc/neutron/plugins/ml2/openvswitch_agent.ini, had to specify: bridge_mappings = physnet1:br-ex

flovax gravatar imageflovax ( 2016-05-13 13:28:12 -0600 )edit

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Asked: 2014-12-15 10:22:11 -0600

Seen: 2,926 times

Last updated: Dec 16 '14