[ovs-discuss] [openflow-discuss] putting switches in their own namespace in mininet using openVswitch

[Justin Pettit]

If you only run network namespaces, it's pretty easy to run multiple instances of OVS.  I touched on it briefly a couple of weeks ago on the ovs-discuss mailing list:

    http://openvswitch.org/pipermail/discuss/2013-February/009157.html

As you mentioned, you'll need to have each ovsdb-server and ovs-vswitchd pair use a separate rundir, config files, etc, since they'll be in the same process and file namespaces.

Also, Ramana, please don't cross-post mailing lists in the future.

--Justin


On Mar 9, 2013, at 12:27 AM, Bob Lantz <rlantz at cs.stanford.edu> wrote:

> To clarify, I believe the default configuration of the OVS daemons uses unix domain sockets, which is a perfectly good idea but may break when your switch and daemons are in different namespaces.
> 
> On Mar 9, 2013, at 12:19 AM, Bob Lantz <rlantz at cs.stanford.edu> wrote:
> 
>> Mininet doesn't currently support that configuration because I wasn't able to come up with an easy way to make it work out of the box with the Ubuntu OVS packages. I suspect one problem could be that unix domain sockets don't work across network namespaces, even with a shared filesystem, and openvswitch-switch uses them to communicate with ovs-vswitchd and ovsdb-server. If that's the case, then a) it doesn't seem like correct kernel behavior to me, b) it could also be the root cause of the annoying x11 forwarding breakage, and c) there could be workarounds like using a network connection on the virtual control network, but it probably requires further investigation and my understanding of all of the relevant pieces is incomplete and possibly in error.
>> 
>> Very few people have asked me about this - I think emulating a virtual control network (controlled by OpenFlow no less - turtles all the way down!) is not a popular thing to do on Mininet, although it can certainly be done as evidenced by the --innamespace command line option.
>> 
>> -Bob
>> 
>> On Mar 8, 2013, at 10:40 PM, Ramana Reddy <gtvrreddy at gmail.com> wrote:
>> 
>>> Hi All, 
>>> I want to put switches in their own name space in mininet using open Vswitch.
>>> But mininet website telling that open Vswitch does not support this feature.
>>> 
>>> http://mininet.github.com/walkthrough/#everything-in-its-own-namespace-user-switch-only
>>> 
>>> $ sudo mn --innamespace --switch user
>>> Instead of using loopback, the switches will talk to the controller through a separately bridged control connection. By itself, this option is not terribly useful, but it does provide an example of how to isolate different switches.
>>> 
>>> Note that this option does not (as of 11/19/12) work with Open vSwitch.
>>> 
>>> I want to know which version of open Vswitch supports this feature. 
>>> 
>>> 
>>> 
>>> Thanks,
>>> 
>>> Ramana. 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> openflow-discuss mailing list
>>> openflow-discuss at lists.stanford.edu
>>> https://mailman.stanford.edu/mailman/listinfo/openflow-discuss
>> 
> 
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