[ovs-discuss] problem when using DHCP on "internal interface" of openvswitch

[liuxy]

thanks,  I do it flowing the answer, and the br0 can get IP from DHCP, but
when there are more than one "internal" interfaces in the bridge br0,  can
other interfaces get IP from DHCP? For example:

ovs-vsctl add-br br0
ovs-vsctl add-port br0 eth0
ifconfig eth0 0.0.0.0

after execute the command above , the  interface "br0" can use DHCP to get
IP

and then  I add another "internal" interface to br0

ovs-ovsctl add-port br0  vif0

and now there are three interfaces in br0 :  br0, eth0 and vif0,  can vif0
use DHCP to get IP ????

thanks a lot for help !!

2012/11/12 Ben Pfaff <blp at nicira.com>

> On Mon, Nov 12, 2012 at 04:16:58PM +0800, liuxy wrote:
> >   I want to use DHCP on the "internal" network interface of ovs, but it
> > can't works. I can exactly set  the static ip using "ifconfig", but when
> I
> > use the "dhclient " to set DHCP on the interface, it fails, I am sure
> > that the DHCP server works well !  the steps like this:
>
> This is a FAQ.
>
> Q: I created a bridge and added my Ethernet port to it, using commands
>    like these:
>
>        ovs-vsctl add-br br0
>        ovs-vsctl add-port br0 eth0
>
>    and as soon as I ran the "add-port" command I lost all connectivity
>    through eth0.  Help!
>
> A: A physical Ethernet device that is part of an Open vSwitch bridge
>    should not have an IP address.  If one does, then that IP address
>    will not be fully functional.
>
>    You can restore functionality by moving the IP address to an Open
>    vSwitch "internal" device, such as the network device named after
>    the bridge itself.  For example, assuming that eth0's IP address is
>    192.168.128.5, you could run the commands below to fix up the
>    situation:
>
>        ifconfig eth0 0.0.0.0
>        ifconfig br0 192.168.128.5
>
>    (If your only connection to the machine running OVS is through the
>    IP address in question, then you would want to run all of these
>    commands on a single command line, or put them into a script.)  If
>    there were any additional routes assigned to eth0, then you would
>    also want to use commands to adjust these routes to go through br0.
>
>    If you use DHCP to obtain an IP address, then you should kill the
>    DHCP client that was listening on the physical Ethernet interface
>    (e.g. eth0) and start one listening on the internal interface
>    (e.g. br0).  You might still need to manually clear the IP address
>    from the physical interface (e.g. with "ifconfig eth0 0.0.0.0").
>
>    There is no compelling reason why Open vSwitch must work this way.
>    However, this is the way that the Linux kernel bridge module has
>    always worked, so it's a model that those accustomed to Linux
>    bridging are already used to.  Also, the model that most people
>    expect is not implementable without kernel changes on all the
>    versions of Linux that Open vSwitch supports.
>
>    By the way, this issue is not specific to physical Ethernet
>    devices.  It applies to all network devices except Open vswitch
>    "internal" devices.
>
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