Re: [Xen-devel] virbr0/bridge: No such file or directory, rhel6 bridge-utils IGMP snooping

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Mon, Aug 29, 2011 at 06:44:24PM -0500, Scott Meyers wrote:
> 
> In response to your questions:
>  
> 
> > - do you have ip_forwarding (routing) enabled in dom0?
> 
> No. That was not mentioned or required according to your tutorial.
> 

NAT requires ip_forwarding/routing! This is a generic requirement for all Linux 
NAT stuff,
be it Xen or something else.

>  
> > - How are your firewall rules in dom0?
> 
> 
> Disabled
> 

Then it obviously won't work!
When dnsmasq starts it should add the firewall rules for NAT.


>  
> > - Is dnsmasq running?
> No, dsnmasq was not running. I started dnsmasq, but didn't solve the problem.
> 

dnsmasq acts as a dhcp server and DNS server for virbr0 bridge, 
so you definitely need it running!


>  
> 
> > - Do you see domU dhcp requests in system logs (from dnsmasq) ?
> 
> 
> No. I always set dhcp off. I use static ips.
> 

What IP did you configure in the VM? 
Could you ping the gateway (dom0 IP on virbr0) from the VM?


> 
> > - After the domU is started run "brctl show" - is the domU vif connected to 
> > virbr0 bridge?
> 
> 
> It showed:
> 
> bridge name bridge id STP enabled interfaces
> virbr0 8000.feffffffffff yes
> 

So the VM is NOT connected to virbr0 at all!
Do you have xen-netback driver loaded in dom0 kernel?

> 
> > - Run "tcpdump -i virbr0 -nn" - do you see the traffic from the vm?


Did tcpdump show any traffic?


> > - Does the domU get an IP? 
> 
> Nope.
> 
> Why Xen v4.x is so buggy and difficult to deal with? I didn't have these 
> problems using version 3.x. Does that mean v4 in still in beta?
> 

4.x is not in beta. 

When building a platform on your own, you need to understand
how things work and configure everything properly.

> We are planning to use v4 on a production server. Can we trust this system?
> 

Yes, when it's properly configured.


-- Pasi


>  
> 
>  
> 
> > Date: Tue, 30 Aug 2011 00:23:24 +0300
> > From: pasik@xxxxxx
> > To: scottmeyers@xxxxxxxx
> > CC: xen-devel@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: [Xen-devel] virbr0/bridge: No such file or directory, rhel6 
> > bridge-utils IGMP snooping
> > 
> > On Mon, Aug 29, 2011 at 03:52:59PM -0500, Scott Meyers wrote:
> >
> 
> > virbr0 is created by libvirtd/dnsmasq, so it's not really part of Xen.
> > 
> > Anyway, some things to verify:
> 
> 
>                                         

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