[Fedora-xen] Fedora Core 8 + Xenbr0 + network bridging?

[John Summerfield]

Christian Lahti wrote:
> Hi Mark:
>  
> Thank you very much for your response, I did indeed read the original poster as Dale by mistake :)  So what you are saying makes perfect sense to me and sounds like exactly what we are after, I will have 3 vlans to bridge myself ultimately.  My next question is the relative merits of RHEL5.1 as compared to Fedora 8.  Obviously I would prefer the stable enterprise release rather than bleeding edge Fedora, but has fully virtualized windows performance been fixed in this release?  At any rate I am looking forward to getting this up and running tomorrow!
>  
> /Christian
>  
> 
> ________________________________
> 
> From: Mark Nielsen [mailto:mnielsen at redhat.com]
> Sent: Sat 12/1/2007 3:19 PM
> To: Christian Lahti
> Subject: Re: [Fedora-xen] Fedora Core 8 + Xenbr0 + network bridging?
> 
> 
> 
> hmm, did you mean "Hi Mark" ??
> 
> I have 8 Dell 2950s running RHEL 5.1 (new libvirt with that funky NAT
> they added). I have 4 NICs in each; 2 copper, 2 fiber. I bond the 2
> copper (eth0 and eth1) and call it bond0. bond0 carries my "private" IP
> for cluster suite communications on the dom0 (physical) cluster.
> 
> Then I bond eth2 and eth3 (fiber) in to bond1. I lay down the public
> network for the dom0 cluster on bond1.100 (for example, that would be
> VLAN 100). I also add many (up to 10 or so now) VLANs on bond1
> (bond1.20, bond1.21, bond1.22, etc). Then I create xen bridges to each
> of these bond/VLAN devices. This allows me to put any particular VM on
> any particular (or combination up to 3) of these xen bridged bonded VLAN
> device.
> 
> My document explains, in detail, how to do all of this :) The only added
> step is that I have to "undefine" (virsh net-undefine default) the
> default network that the new libvirt creates (virbr0). Even with this
> new NAT thing they added, I've been told (by our devs) that the
> preferred way to do static network configurations is with the method I
> lay out. NAT is more for dynamic networks (cable modems, dial-up, wifi,
> etc).
> 
> I'm pretty sure there weren't any significant changes in Fedora 8 (we've
> dropped the word "core" now, btw) that don't exist in RHEL 5.1 with
> respects to the network. 5.0 -> 5.1 is when that NAT change came down
> the pipe.
> 
> Mark
> 
> p.s. I'm happy to answer any other questions you may have about my
> document. I'm quite certain that, if you follow it, you'll have what
> you're looking for.
> 
> Christian Lahti wrote:
>> Hi Dale:
>>
>> I work with David who posted the original question to the mailing
>> list.  I think we need to give a bit more background info on what we
>> are trying to do.  We are running a mixed environment of mostly CentOS
>> 3, 4and 5, we do have a few windows servers and XP systems as well. 
>> We are looking to virtualize all these platforms.  Normally we have a
>> bonded pair of NICs for the physical hosts, we were able to get this
>> running using CentOS 5 x86_64 with no problems, the guest machines use
>> the bonded pair in bridged mode as expected after a bit of tweaking. 
>> The biggest issue we found with EL5 is that windows guest performace
>> is dismal at best, hence our decision to have a look at Fedora Core 8
>> x86_64.  I am happy to report that performance for all of our guest
>> platforms is *very* good with FC8, but it seems that libvirt changed
>> the way networking is setup for Xen.  The default NAT configuration is
>> pretty useless for production server environment.  Thanks to the
>> mailing list we are now able to bridge a single NIC on FC8 (like eth0
>> for example), but we cannot figure out how to get a bridge for bond0
>> (comprised of eth0 and eth1) defined and available to Xen.  All the
>> tweaks that worked find on EL5 have not worked so far on FC8.  I am
>> going to review your document tomorrow and give it a try, but any idea
>> on whether your methodology will work on FC8 and libvirt?  I am
>> willing to blow a Sunday to get this worked out once and for all :)
>>
>> Basically we are after good performance on both para and fully
>> virtualized guests using a bonded pair of GB NICs for speed and
>> redundancy.  If this can be achieved with enterprise linux then that
>> would be preferable, but we will go FC8 if the bonding thing can be
>> sorted out.  By the way Xensource 4.x looks to be a respin of RHEL5
>> and has pretty good performance but their free version is limited to
>> 32bit (and hence 4GB ram).  Adding the clustering failover is the next
>> step of course :)
>>
>> Thanks again for the help so far.

In your position, I might consider another Sunday to see whether the f8 
tools run on C5, and not, then what's needed.

The -xen kernel's probably needed along with the most obvious *virt*. 
There might not be a lot of building to do, and the odds are good that a 
Fedora kernel will "just work," depending on whether you need extra drivers.





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Cheers
John

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