Network problems with 1950 and Xen

[Ronan Mullally]

Hi Matthias,

On Fri, 3 Aug 2007, Matthias Saou wrote:

> I'm running RHEL5 Xen Hosts on PE1950s and PE2950s without seeing this
> problem. Have you looked closer at the logs? Were you able to check the
> network configuration after loosing the connection?

There is nothing unusual in the logs.  xenbr0 gets set up correctly.
peth0 and vif0.0 get placed in the bridge and dom0's networking stops
working.

A packet trace of peth0 shows packets leaving the box, a packet trace on
the far end shows them being recevied and replied to, but dom0 never sees
the incoming response.  domU hosts however work fine.

I've gone through the steps outlined at:

  http://mywiki.ncsa.uiuc.edu/wiki/Dell_PE1950_NIC_Firmware_Workaround

and the problem goes away, however in the process I loose LAN access to
the BMC, which given that this box is going to be remotely hosted, is not
an acceptible solution.

> But the only real "problems" I'm seeing with Xen Hosts and my networking
> setups are :
> - Static routes get discarded by the xend startup script.
> - When a non-xen bridge is already configured, the xend startup script
> removes the default gateway.
>
> This of course might very well be RHEL5 xend script specific.

I've managed to do some funky bridge configuration on RHEL5 for one of my
customers.  Each physical machine has a two port bond, that bond has
number of VLANs presented to it, and these VLANs are put in various
bridges (front, back, mgmt) for presentation to the domUs.  Apart from
having to tweak some of the arguments to network-bridge it all worked
without any problems.


-Ronan