Use network DHCP server with bridge interface?

Community Support
1

Hi,

Right now I have one host with one bridget network (br0) and one 1GB NIC.

This is the network configuration from the host (Debian 8, OpenNebula 4.14.2):

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto br0
iface br0 inet dhcp
  bridge_ports eth0
  bridge_fd 9
  bridge_hello 2
  bridge_maxage 12
  bridge_stp off

How can I use a virtual machine with our internal DNS/DHCP server?

Sunstone => Create Virtual Network:

  1. What should I choose for “Conf” => “Network model”?
  2. “Ethernet” looks right to me for “Addresses”.

I have only one port with no VLAN defined. Only the bridge setup from above.

Thanks for your input.

2

Hi,

I tested a little bit how that could be done but did not find a solution!
I thought using Ethernet too and then enter an ethernet address and the amount of adresses available. Seemed logic to me.
But the VM fails to start with “can’t create domain”.
If I am using the normal setup with dhcp through one, then the VM starts without trouble.
I am not sure how to use the LAN in bridge mode.

Regards,
Bernhard

3

I have a similar config. I’m using Ethernet networks. but my hosts are using open vswitch bridges instead of linux bridging. But it works. I’m able to get DHCP and PXE boot instances.

I’m still a newbie but I’d make sure that when you instantiate your instance that you see vnet interfaces added to br0. If that’s not happening your host might be added with the right network driver or the scripts aren’t able to execute brctl.

4

@kansfv

What do you mean with “I am using the normal setup with dhcp through”?

I have reconfigured my host to use “ovs” but it didn’t works. I got this error:

Fri Feb  5 11:08:41 2016 [Z0][VM][I]: New state is ACTIVE
Fri Feb  5 11:08:41 2016 [Z0][VM][I]: New LCM state is PROLOG
Fri Feb  5 11:08:41 2016 [Z0][VM][I]: New LCM state is BOOT
Fri Feb  5 11:08:41 2016 [Z0][VMM][I]: Generating deployment file: /var/lib/one/vms/10/deployment.0
Fri Feb  5 11:08:41 2016 [Z0][VMM][I]: ExitCode: 0
Fri Feb  5 11:08:41 2016 [Z0][VMM][I]: Successfully execute network driver operation: pre.
Fri
 Feb  5 11:08:41 2016 [Z0][VMM][I]: Command execution fail: cat <<
 EOT | /var/tmp/one/vmm/kvm/deploy 
'/var/lib/one//datastores/0/10/deployment.0' 'localhost' 10 localhost
Fri Feb  5 11:08:41 2016 [Z0][VMM][I]: error: Failed to create domain from /var/lib/one//datastores/0/10/deployment.0
Fri Feb  5 11:08:41 2016 [Z0][VMM][I]: error: Unable to add bridge br0 port vnet0: Operation not supported
Fri Feb  5 11:08:41 2016 [Z0][VMM][E]: Could not create domain from /var/lib/one//datastores/0/10/deployment.0
Fri Feb  5 11:08:41 2016 [Z0][VMM][I]: ExitCode: 255
Fri Feb  5 11:08:41 2016 [Z0][VMM][I]: Failed to execute virtualization driver operation: deploy.

Bridge mode on the host is working perfekt.

Thanks

5

I use the DHCP from the One Server not from the network switch.
Can you do an brctl show?

6

You can’t just change your host to use ovs. you need to install and setup ovs on your host. If this is what you did. you will want to make sure that you have all of your names right.

A host using ovs will expect the default bridge be named ovsbr0 instead of br0. that error about unable to add bridge port is definitely a problem. But I suspect you don’t have ovs set up on this host. so you might have some conflicting configs between ovs and linux bridging.