CentOS - Jan 2010 - Setup multiple bridges for use with KVM

Running CentOS 5.4 x64.

Have successfully bridged eth2 with br2 by following the instructions here:
http://wiki.libvirt.org/page/Networking (under the RHEL section)

Have been running several KVM VMs successfully via this bridge.

I am now trying to bridge additional interfaces by using the same routine.
Each bridge is named to correspond with the ethX device its bridged with.

Example of ifcfg-eth0 script:
DEVICE=eth0
HWADDR=00:16:76:D6:C9:45
ONBOOT=yes
BRIDGE=br0

then of ifcfg-br0 script:
DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes
DELAY=0

This is repeated 3 times for eth0-eth2 and br0-br2.

I've read somewhere that STP needs to be enabled when using multiple
bridges. I've tried adding STP=on to the ifcfg-brX scripts but with the same
result. Yes, brctl shows that STP is on.

The original bridge eth2-br2 continues to work but I can't get any traffic
across any other bridge. Either by dhcp or static ips.

Is multiple bridges a possibility?

Previous to moving to KVM I was running Xen Server on the same hardware. I
am just trying to recreate the network setup I had. I believe Xen Server
runs on top of a linux platform so such a thing should be possible.

Thanks,

Jacob
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Jacob Hydeman wrote on Sat, 9 Jan 2010 18:15:14 -0800:
> BOOTPROTO=dhcp
I'm using the same setup for multiple bridges for Xen, no problem. But I 
use static IP addresses. You *have* to use IP numbers from different 
subnets.
> I've read somewhere that STP needs to be enabled when using multiple
> bridges
No.

Kai

-- 
Get your web at Conactive Internet Services: http://www.conactive.com

On Sat, Jan 9, 2010 at 11:15 PM, Jacob Hydeman <jhydeman at gmail.com>
wrote:
> Running CentOS 5.4 x64.
>
> Have successfully bridged eth2 with br2 by following the instructions here:
> http://wiki.libvirt.org/page/Networking (under the RHEL section)
>
> Have been running several KVM VMs successfully via this bridge.
>
> I am now trying to bridge additional interfaces by using the same routine.
> Each bridge is named to correspond with the ethX device its bridged with.
>
> Example of ifcfg-eth0 script:
> DEVICE=eth0
> HWADDR=00:16:76:D6:C9:45
> ONBOOT=yes
> BRIDGE=br0
>
> then of ifcfg-br0 script:
> DEVICE=br0
> TYPE=Bridge
> BOOTPROTO=dhcp
> ONBOOT=yes
> DELAY=0
>
> This is repeated 3 times for eth0-eth2 and br0-br2.
>
> I've read somewhere that STP needs to be enabled when using multiple
> bridges. I've tried adding STP=on to the ifcfg-brX scripts but with the
same
> result. Yes, brctl shows that STP is on.
>
> The original bridge eth2-br2 continues to work but I can't get any
traffic
> across any other bridge. Either by dhcp or static ips.
>
> Is multiple bridges a possibility?
>
> Previous to moving to KVM I was running Xen Server on the same hardware. I
> am just trying to recreate the network setup I had. I believe Xen Server
> runs on top of a linux platform so such a thing should be possible.
I am curious as to what exactly is your topology and which is its
intended use. I have found no issues wrt STP but you seemingly need to
assign different vlans to your VM interfaces, depending on which
bridge they are attached to (i.e. roughly 1 bridge = 1 vlan).
I am confused about what interfaces are attached to which bridge in
your setup, would like to see the scripts you are using to start your
VMs...
Thank you in advance

-- 
Eduardo Grosclaude
Universidad Nacional del Comahue
Neuquen, Argentina