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List:       openvswitch-discuss
Subject:    [ovs-discuss] Setting the HW addr of bridge internal interface -- issues
From:       jpettit () nicira ! com (Justin Pettit)
Date:       2012-12-26 7:51:59
Message-ID: B508E3D0-8B27-45E2-83A0-A2707CAF878F () nicira ! com
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You should be able to set it with a command similar to the following:

	ovs-vsctl set bridge br0 other-config:hwaddr=aa:bb:cc:dd:ee:ff

There are a bunch of other configuration parameters you may want to look at here:

	http://openvswitch.org/ovs-vswitchd.conf.db.5.pdf

Hope that helps.

--Justin


On Dec 25, 2012, at 11:43 PM, Florian Daniel Otel <florian.otel at gmail.com> wrote:

> Hello all, 
> 
> First, a disclaimer: As I'm relatively new to OVS (and to this list) pls point me \
> to the correct resource(s) if this is a known issue / solution.  TIA.  
> Setup: 
> 
> I am trying to do some testing with OVS inside a VM.  The challenge is that in the \
> environment I'm working the Host does a static mapping btw. the MAC address of  \
> VM's primary interface ("eth0" henceforth) and the  ip address it assigns to that \
> VM. Since my tests involve putting that primary interface ("eth0")  in an OVS \
> bridge as per the OVS standard FAQ I need to first zero out the ip address of the \
> said interface, add  "eth0" to my bridge and then assign "eth0" ip address  to \
> "br0" -- i.e. to the bridge internal interface (then reset the default gateway etc. \
> etc accordingly...) 
> Now, given the peculiarities of my setup that swap doesn't work straight away since \
> the MAC addrs of "eth0" and "br0" are different, so the connectivity to the outside \
> world is cut off by the host (it still responds to e.g. ARP traffic by sending the \
> responses to "eth0" MAC address).  
> The way I solve this is not only to assign to "br0" the  IP addr of  "eth0"  but \
> swap MAC addresses as well btw the two interfaces, using smth like this:  
> OLDHWADDR=`cat /sys/class/net/eth0/address`
> NEWHWADDR=`cat /sys/class/net/br0/address`
> 
> ifconfig eth0 down
> ifconfig eth0 hw ether $NEWHWADDR
> ifconfig eth0 up 
> 
> ifconfig br0 hw ether $OLDHWADDR
> 
> As a result "br0" has "eth0" IP _and_ MAC addrs, and all works well. 
> 
> Problem: 
> 
> As soon as I do _any_  subsequent operations in OVS -- e.g. add another (unrelated) \
> bridge "br1" , add a port to "br1" etc. etc -- the MAC address of "br0" is  reset \
> to its initial value. Which, given my setup, cuts off the VM from the outside world \
> again.  
> Questions:
> 
> 1) Is this intended behavior ? If yes, any logic behind it and can that be altered \
> ?  
> 2) How can I make the MAC address assignment to a bridge internal interface "stick" \
> i.e. make it a one time only operation  ?  Goes w/o saying that, while I can script \
> any subsequent  OVS operations by appending them with a command that re-sets the \
> "br0" MAC addr to the one I need to, that's nothing short of a horrible \
> workaround.. 
> I've confirmed this behavior on Ubuntu 12.04 x64 with both vannilla packages \
> (1.4.0.1-1ubuntu1.3) and the code currently in the official GitHub repo.  LMK if \
> there is any more info needed.  
> TIA for all the help / advice / pointers,
> 
> Florian _______________________________________________
> discuss mailing list
> discuss at openvswitch.org
> http://openvswitch.org/mailman/listinfo/discuss


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