[CentOS] centos6 xen

Alain Péan alain.pean at lpp.polytechnique.fr
Thu Jul 28 12:04:11 UTC 2011

Le 28/07/2011 13:27, Tom H a écrit :
> On Thu, Jul 28, 2011 at 6:31 AM, Rudi Ahlers<Rudi at softdux.com>  wrote:
>> On Thu, Jul 28, 2011 at 11:23 AM, Peter Peltonen
>> <peter.peltonen at gmail.com>  wrote:
>>> On Thu, Jul 28, 2011 at 11:56 AM, John R. Dennison<jrd at gerdesas.com>  wrote:
>>>> On Thu, Jul 28, 2011 at 10:53:23AM +0200, Juergen Gotteswinter wrote:
>>>>> i think i am not the only one who wants to stay with with xen :)
>>>> Far from it.  Xen still has a place as a dom0.
>>> What are the reasons for people staying with Xen as dom0, just the
>>> learning curve? Or are there some technical considerations as well?
>> KVM is not as mature as XEN. yet....? And if you want to use a so
>> called Enterprise Operating System like CentOS, then you'd probably
>> expect a stable and "enterprise" grade virtualization kernel as well.
>> KVM, IMO (and others as well ) is not enterprise ready yet.
> I'd edit what you've said in two ways.
> 1. The tools to manage KVM aren't as mature as the tools to manage Xen.
> 2. A so-called Enterprise Operating System like RHEL.

IMO, KVM in itself is not the problem, it is the lack of management 
solutions as mature as Vmware or XenServer, and lack of (other) 
Enterprise support, yet (for example ESXi is supported by Dell and 
others). Libvirt, in my opinion, and others, is not an Enterprise grade 

I am using KVM in a production environnement, for windows (2003 R2, 2008 
R2), and Linux (Ubuntu, CentOS...). I don't see much difference with 
ESXi with the same kind of VMs (I never used Xen).
But I am not using KVM with CentOS (or Red Hat), but under Debian, with 
Proxmox-ve. In the spirit of ESXi, it is a bare metal installer, which 
configure everything (bridge, LVM for snapshots, web interface 
management). I would not say it is as well known or mature as Vmware, 
but it fills my needs. The most interesting thing for me is the web 
management interface, which is very clear, permits to create or modify a 
VM, backup it, add a new storage, live migrate the VM (with shared 
storage), so it is a very convenient management solution, available from 
whatever system you want. Only a web browser supporting javascrip is 
needed, this is rather common these days...

And the most important point for me is that KVM is included in mainline 
kernel, that is available under every linux distribution (RHEL, Ubuntu, 
Debian, Suse, etc...), and will remain free source (GPL). So, if 
Proxmox-ve disappears, I can rather easily migrate to another solution. 
The other important point is that behind, it is standard Linux, not 
close as Vmware, so you can access eveything, add the package you want 
very easily.

One reason why RedHat discarded Xen was it was not included in the 
mainline kernel, so was difficult to maintain. You see, you have to 
compile your own kernel, that will not be supported upstream...

I am waiting to see the free (source) Java (so Linux) version of RHEVM, 
but I saw nothing appear yet, and I fear it will not be as handy 
Proxmox-ve Web interface and solution is, and not so open...

My two cents.


Alain Péan - LPP/CNRS
Administrateur Système/Réseau
Laboratoire de Physique des Plasmas - UMR 7648
Observatoire de Saint-Maur
4, av de Neptune, Bat. A
94100 Saint-Maur des Fossés
Tel : 01-45-11-42-39 - Fax : 01-48-89-44-33

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