Nova network breaks access to Internet on compute node

asked 2014-01-30 10:06:15 -0600

JamieB gravatar image

updated 2014-01-30 10:08:10 -0600

I have been struggling with a simple network setup using OpenStack Havana over the past week, and have exhausted all available resources. Really hoping someone can point me in the right direction.

Here is my extremely simple topology:

I have a single Internet gateway router on This router doesn't do DHCP but handles DNS. Connected to the above router is a switch ("external switch").

I have a second switch that is not connected to any router, which I want to use for the private side of the network ("internal switch").

I have two servers (controller and compute1). Both servers have two NICs and run Ubuntu Server 12.04.3 LTS (x64).

I have plugged eth0 of both servers into the internal switch. I have plugged eth1 of both servers into the external switch.

The controller server has the network interfaces configured as follows:

auto eth0
iface eth0 inet static

auto eth1
iface eth1 inet static

The compute1 server has the network interfaces configured as follows:

auto eth0
iface eth0 inet static

auto br100
iface br100 inet static
bridge_ports eth1
bridge_stp off
bridge_maxwait 0
bridge_fd 0

I have basically followed the Ubuntu installation guide step-by-step. I don't want to run a separate Neutron server, I am happy to use the legacy nova network configuration in our production setup.

I have managed to run the dashboard and launch new instances without a problem using the instructions in the installation guide.

However, here is where the problem is...

Once I launch a VM instance, br100 gets reconfigured by OpenStack to IP and from this point forward I am unable to ping the Internet gateway router from the compute node (or any VMs). As such neither the compute node nor VMs have access to the Internet.

I'm not sure what I am doing wrong, all my configurations are exactly as shown in the step-by-step installation, though of course that doesn't go into detail of gateways (etc).

I would be extremely grateful of any help as I really can't understand where the problem is, and this seems to me like a really simple network setup, so not sure why it doesn't work.

Many thanks!

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I have the exact same issue. Have you found a solution?

delphyne gravatar imagedelphyne ( 2014-05-09 00:14:03 -0600 )edit

how did you do: nova network-create ?

chladic01 gravatar imagechladic01 ( 2015-08-28 03:42:34 -0600 )edit

1 answer

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answered 2016-09-29 23:46:05 -0600

Sudhin gravatar image


I was also having the same issue. But i fixed it by changing /etc/resolv.conf file with adding name-server as

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Asked: 2014-01-30 10:06:15 -0600

Seen: 541 times

Last updated: Sep 29 '16