[ovs-discuss] Openvswitch and Linux containers

Aishwarya aishu85 at gmail.com
Sat Oct 1 05:18:04 UTC 2011


Hi Jesse,

By one instance of OVS, do you mean I should only create one bridge, or one instance of vswitchd? Right now, I am creating only one instance of vswitchd on the host, but 2 bridges, one on the host for the containers to communicate to the.host and the other inside the container so that the vms can be attached to that one. Creating the second bridge is where I am facing an issue with the previous error. Seems like you are saying this is not needed. Is that correct? I will look at KVM for more information.

I could successfully set up UML to UML communication without containers on a host. It's confusing because now the UMLs are created within the container. So, I am just wondering how the UMLs will use OVS to communicate if They cannot be attached to thr bridge because of the connection error.

Thanks,
Aish

On Sep 30, 2011, at 8:18 PM, Jesse Gross <jesse at nicira.com> wrote:

> On Fri, Sep 30, 2011 at 8:10 PM, Aishwarya <aishu85 at gmail.com> wrote:
>> Hi Jesse,
>> 
>> So I did the following:
>> 1. Started openvswitch on the host.
>> 2. Created a bridge and interface to attach the container to, and started
>> the containers. The containers are able to communicate with the host using
>> ovs.
>> 3. Now, I am starting vms within the container. So, before this I am
>> creating another bridge within the container to attach the vms to, and also
>> trying to create tap interfaces for the vms to add to teh bridge, as I would
>> do usually without containers. But I get the following error:
>> 
>> Sep 30 19:57:50|00002|stream_unix|ERR|/tmp/stream-unix.25326.0: connection
>> to openvswitch_necessaryfiles_kernel465/ovs_database/db.sock failed:
>> Connection refused
>> 
>> I think vsctl is not able to connect to the database socket. If I run the
>> exact same command from the  base default container where I started
>> openvswitch, I do not get this error. The container is other wise able to
>> get to the directory openvswitch_necessaryfiles_kernel465/ovs_database.  Do
>> you have any idea what could be wrong?
> 
> You should only create one instance of OVS in the entire system.  This
> is exactly analogous to the setup used in any other virtualization
> system, such as KVM or Xen.  Please look at those for background on
> switching for virtualization.
> 
> Regardless, I'm assuming that the reason why OVS cannot find the
> database socket is because the database server is not running in the
> container.



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