qemu-kvm vde networking [was Re: Sorry to bother you]

Christian Rößner christian at roessner-net.com
Wed Mar 31 17:15:46 BST 2010


first of all: Very much thanks for the time you take to answer.

Putting KVM into PPA would really be something that I would like. I already tried to build it, but at the moment lucid is broken on my server ;-) (mdadm/lvm bug).

I am going to write the MIR. But first I got arp-tools and want to test arp-flooding on the switch. Also checking performance from 2 client pairs concurrently on the switch with netcat. Afterwards I will do it.

Thanks very, very much and I hope vde will find its way to main and kvm into PPA ;-)

Am 31.03.2010 um 16:41 schrieb Dustin Kirkland:

> On Wed, 2010-03-31 at 10:32 +0200, Christian Rößner wrote:
>> excuse me please that I contact you directly. Before I go building my
>> own kvm package with vde support I want to ask you, if you could give
>> me detailed arguments, why vde is not in main repo and why you
>> consider it not secure (enough; you said _more secure than_).
>> I wait from release to release always missing the vde support and I
>> can not understand why you do not include it. Where are the reasons?
>> And why is vde not in main?
>> I have really good experiences with vde and kvm for years now. I use
>> KVM for several minor internet service providers here in Germany and
>> all the servers use vde, cause it is ingenious. 
>> Seperating local guest communication from outside. And!!!: You do not
>> need bridging network, which makes firewalling so much easier. And you
>> still can reach the host operating system from the guests, which gives
>> you are real intranet.
>> So there are so many arguments FOR vde. Any other solution is really a
>> pain. And I tested them all! I am not a newie.
>> So if security is an argument, then I would say ok.
> Hi Christian, thanks for the kind, detailed email.  I hope you don't
> mind that I'm CC'ing this response to the ubuntu-server@ and
> ubuntu-devel@ mailing lists, as this has come up a few times, and I'd
> like to collate a single response here...
> Okay, let me eat my words on the security aspect of VDE...  I can't say
> that VDE is more or less secure than the other recommended networking
> models at:
> * https://help.ubuntu.com/community/KVM/Networking
> What I can say is that:
> a) Per discussions with upstream QEMU, tap is the 'official',
> 'supported', 'recommended' networking mechanism for QEMU and KVM
>  * Upstream also says that VDE performance is poor because it doesn't
> support offloading, tap networking should suffice for vast majority of
> users, VDE security is mostly untested for things like mac flooding and
> ip spoofing, and upstream does virtually no testing of VDE before they
> release
> b) The required library, libvdeplug2-dev and its source package, vde2
> are in Ubuntu Universe, while qemu-kvm is in Ubuntu Main (Main packages
> cannot build against libraries in Universe)
> c) Canonical-long-term-supported KVM in Ubuntu's Lucid Main repository
> will not differ from Upstream's recommendation on this point
> d) The other networking models (ie, through KVM/Libvirt) are *far* more
> heavily tested over the last 2 years of Ubuntu Hypervisor development,
> through Hardy->Intrepid->Jaunty->Karmic->Lucid.
> What we can offer is this:
> 1) A qemu-kvm package in a PPA managed by ~ubuntu-virt in Launchpad
> that does build against libvdeplug2-dev
>  * We can try to keep this package "in sync" with what goes into Lucid
> (ie, upload at the same time and just enable vde in the PPA build)
>  * But any problems or issues caused by or related to VDE will be
> supported on a best-effort, wishlist-priority basis (as are most PPA
> builds)
> 2) If someone who has interest in, and experience with VDE will write
> the Main Inclusion Report (MIR) for vde2, we can propose vde2 for
> inclusion in Main for Lucid+1, and I'll enable VDE in the qemu-kvm
> builds for Lucid+1 if the MIR is approved.  See:
>  * https://wiki.ubuntu.com/MainInclusionProcess
> I have marked your bug a duplicate of another one, marked wont-fix
> against Lucid, but marked it triaged/high for Lucid+1, at:
>  * https://bugs.edge.launchpad.net/ubuntu/+source/vde2/+bug/253230
>> But please include it. It is an LTS version, so big chance to make
>> this pain an end ;-)
> I understand your concern.  But this is the precise reason why we cannot
> just enable VDE networking at this time.  We're at a Beta2 freeze for
> our LTS release.  I appreciate your confidence in VDE -- that will
> support the MIR process for Lucid+1.  But the vast majority of testing
> and stabilization of Ubuntu's Hypervisor stack has been intensely
> focused on the KVM+Libvirt networking model.  Slipping VDE networking
> into Ubuntu 10.04 LTS at Beta2, and then committing to supporting that
> code for 5 years is simply not something we can do, I'm sorry.
>> As you read, I am from Germany. Sometimes my English may sound a
>> little bit rough, but I do not mean it like this.
> No problem ;-)
> Cheers,
> -- 
> :-Dustin
> Dustin Kirkland
> Canonical, LTD
> kirkland at canonical.com
> GPG: 1024D/83A61194

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