[CentOS-virt] Xen 3.3.1 on CentOS 5.2 - networking problem with bond

Fri Mar 13 18:57:05 UTC 2009
Chris Brown <seebrown99 at gmail.com>


I'm new to the list and new to Xen, so please be gentle with me! ;-)

I've got a CentOS 5.2 x86_64 machine with two interfaces (eth0 and eth1
unsurprisingly) bonded into bond0 in mode 4, and a Cisco switch set up with
LACP to suit.  I didn't select Xen at install time as I wanted to install
Xen 3.3.1 from the gitco repo.  After installing and yum updating, I added
the gitco repo and gid a groupinstall Virtualization.  No problem, Xen 3.3.1
installed on CentOS 5.2 and rebooted OK.

I disabled Xen networking, and manually added my own bridge device, br0 and
moved my IP address off bond0 and onto br0.  I applied the patch from
Bugzilla which changes the network startup order so that bond interfaces
will join bridges properly.  I enabled ip routing.  Rebooted again to test,
and all works - I can ssh the dom0 on the br0 IP address.

I used virt-install to try and install a domu direct from the mirrorservice
repo for CentOS 5.2 and the domu is created, console attches and the initrd
downloads and runs.  Anaconda starts and asks me for language, and IP
details.  I select manual ipv4 config, no ipv6, enter the ipv4 address I
want the domu to have, subnet mask and gateway, and a DNS server address,
and select Ok.

Anaconda says "Determining host name and domain..." and after a couple of
minutes or so, tells me

I can ping the address I gave the domu from the dom0 and from the next hop
(the default gateway for dom0 and domu - another Linux host acting as a
firewall) and I get replies to both.  Both see the same MAC address for the
dom0 ip address - starting with 00:16:36:xx:xx:xx.  On my dom0, if I tcpdump
on bond0 for host <domuaddress>, all I see is arp entries - dom0 address
asking who has domu address and domu address asking who has gateway address
and arp replies.  No traffic, even though I can ping the domu from the
default gateway (ie outside the physical dom0 host).

Any pointers to where I'm going wrong?  It's pretty obvious to me that it is
a network issue of some kind, I just don't know what...

I guess I could try a HVM domu booted from cd-rom with a Knoppix or similar
Live CD so I can test networking?


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