Re: Re: [Xen-users] why my xen is changing the vifX.0 numbers?

[Matej Zary <matej.zary@xxxxxxxxx>]

On Thu, 2010-07-22 at 09:10 -0500, kazabe wrote:
> Hi.
> 
> I have a mail server virutalized on my server (lenny all stable packages).
> 
> Some times is see to mail server stop to work, and when i check, i see
> to the device asigned (vif1.0) now is vif2.0.  if i restart the Dom1
> (the mailserver), now the device is vif3.0, and continue changing the
> numbers.  But if i reboot the dom0, the mailserver can be accesible
> over the vif1.0 device.  What cause that change?  how can i asign
> permanently the vif1.0 device to the mail server? (i have the vif1.0
> device declared in the dom0's firewall, so i need always the same
> device).
> 
> Thanks in advance.
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users

Hi,

vifX.Y is constructed like this:

X = ID of domain (you can check with xm list)
Y = number of eth device in that particular domain with ID X 

So domU with ID 3 and two virtual ethernet cards will have two vifs -
vif3.0 and vif 3.1.


When the domU is created, Xen assigns the next closest and so far unused
ID. Therefore first created domU will have ID 1 (becasue ID 0 is used by
Dom0). Second created domU will have ID 2. But when you reboots the domU
with ID 1, it gets destroyed and then created again - so IDs 0, 1 and 2
were used, next unused one would be 3. So after restart, the domU will
have ID 3.

Restart of dom0 clears the used IDs.

You can configure static name for the vif in particular domU in the domU
cfg file (vifname), so the name of vif will last even in case of restart
and multiple running domUs. And use that name in your dom0 firewall
config. :)


Regards 

Matej

<<attachment: winmail.dat>>

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users