[ovs-discuss] Exporting and importing configurations

Brian Candler b.candler at pobox.com
Fri Apr 11 16:34:41 UTC 2014


On 11/04/2014 16:04, Gurucharan Shetty wrote:
>   if it is a basic
> configuration, you may want to look at
> debian/openvswitch-switch.README.Debian in the git repo that explains
> how to configure Open vSwitch with 'interfaces'. That way, you can
> just copy the interfaces file to a different machine.
Before reading this, what I had done was just the following:

auto br-wan
iface br-wan inet dhcp

auto br-lan
iface br-lan inet static
address 192.168.56.13
netmask 255.255.255.0

auto eth0
iface eth0 inet manual

auto eth1
iface eth1 inet manual

Given that openvswitch was already stored a configuration with bridge 
br-wan containing port eth0, and bridge br-lan containing port eth1, it 
appears to work fine. When the machine comes up, openvswitch starts, the 
bridge interfaces are created, the ports are brought up, and the bridges 
get IP addresses.

Is that a reasonable / supported way of working?

Contrasting this to how debian/openvswitch-switch.README.Debian says to 
do it, it seems to be very complicated. The "bridge with one port" 
example is:

allow-ovs br0
iface br0 inet dhcp
     ovs_type OVSBridge
     ovs_ports eth0

allow-br0 eth0
iface eth0 inet manual
     ovs_bridge br0
     ovs_type OVSPort

That is: you have to say that the bridge br0 exists and contains port 
eth0; but you must also say that the port eth0 exists and it is a member 
of br0?

You don't need to do that with bridge-utils. You'd simply write:

auto eth0
iface eth0 inet manual

auto br-wan
iface br-wan inet dhcp
     bridge_ports eth0


The other thing which concerns me is what it says at the top of that 
README file:

* To use the Linux kernel-based switch implementation, you will need
   to build and install the Open vSwitch kernel module.  To do so, install
   the openvswitch-datapath-source package, then follow the instructions
   given in /usr/share/doc/openvswitch-datapath-source/README.Debian

I haven't installed openvswitch-datapath-{source|dkms} package, and it 
appears to work fine. It has loaded the openvswitch modules which came 
with the kernel.

So is that instruction now incorrect? Can I be sure that I'm using the 
kernel datapath and not the userland data path?

Regards,

Brian.




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