On Tue, May 14, 2013 at 12:07:46PM -0700, Nick wrote:
> Ok that sounds better. So would it be best to use the same eth0 (or
> whatever the physical interface name is) as the untagged network management
> device, or should I somehow create a virtual interface via OVS?
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.
> Also, if I:
>
> 1. Start the database server with an empty database
> 2. Start ovs-vswitchd
> 3. Configure OVS to use eth0
> 4. Start using eth0 normally
> 5. Stop the database server
> 6. Swap out the database to the persistent one
> 7. Start the database server
>
> What happens after #7?
ovs-vswitchd connects to the new database server and updates to the
state in the database.
> Is there something I have to do to get the previous network state
> restored, or does ovs-vswitchd just magically notice that the actual
> running state vs. saved db state is different, and correct the actual
> running state to match?
The latter.
> Also, when the database server is stopped, will the network on eth0 be
> disrupted at all?
No, ovs-vswitchd just keeps the previous configuration in effect until
it reconnects to the database.
_______________________________________________
discuss mailing list
discuss@openvswitch.org
http://openvswitch.org/mailman/listinfo/discuss
