Open Stack

On Fri 12-10-2012 09:32 ›, Salman Toor wrote:
> 
> Some comments are inlined.  On Oct 12, 2012, at 5:55 AM, Matt Joyce
> wrote:
> 
> > - Do I need to create a bridge on the new compute node, when I don't
> > want to run nova-network on that node? I think bridge is only
> > required by the nova-network? But than I get confused with how the
> > network will work? I mean all the traffic of the VMs will go from
> > the node running nova-network? I guess this is not correct right? 
> > 
> > 
> > Depends on how your networking is set up.  But usually a bridge is
> > created for each virtual interface of your instances.  nova-compute
> > will do that for you.
> 
> So with this statement should I understand that the bridge is also
> required/used by nova-compute… right?  In this case I thing the
> traffic will not route through the node that runs the nova-network…. 

The bridge is required to connect the instance interfaces to the host's
interface. Think of the bridge as a virtual switch connecting the
instances and the host machines. It should not affect routing.

> >  
> > If all the traffic from VMs will route through the node running
> > nova-network then should I run nova-network on each compute node as
> > well? Or what is the correct way? 
> > 
> > 
> > depends on your networking configuration.   
> 
> Can you please explain it a bit. I mean in a very simple scenario, 
> 
> node-A, controller node running nova-api, nova-network,
> nova-scheduler, nova-cert, nova-cert, nova-objectstore, nova-volume 
> 
> node-B, only nova-compute 
> 
> Will the traffic of the booted instances on node-B will route from
> node-A or not.
> 

Unfortunately, it still depends... I will try clarify.

In this scenario, all floating_ip traffic will be NAT'ed via the
nova-network host and so will be routed via this host. The fixed_ip
traffic will route via the compute node's default gateway. The gateway
may be the nova-network host, but not necessarily.

Hope this helps.

-- 
Regards.
Andrew Glen-Young