WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

Re: [Xen-users] Creating a paravirtualized guest with Xen 3.4.1 andCento

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Creating a paravirtualized guest with Xen 3.4.1 andCentos 5.3 (64bit)
From: Martin Troester <TroyMcClure@xxxxxx>
Date: Wed, 23 Sep 2009 22:29:59 +0200
Delivery-date: Wed, 23 Sep 2009 13:30:57 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <64D0546C5EBBD147B75DE133D798665F03F3EAF6@xxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <832875840@xxxxxx> <4AB9072E.9090106@xxxxxxxxxxxxx> <4AB930A0.1000703@xxxxxx> <64D0546C5EBBD147B75DE133D798665F03F3EAF6@xxxxxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 2.0.0.23 (X11/20090817)
Jeff,

thanks for the steps to move an existing physical image to a paravirt DomU image. However, I think this only works if both Dom0 and DomU use the same architecture (64bit e.g.). In my case, my host is a 64bit Dom0 with 32bit DomU guests, so I think it's at least necessary to get 32bit kernel and initrd images someplace. Is there an official way to get the released 32bit xen kernel versions to be used on a 64bit host? Otherwise there's no problem to get them manually, but that means not getting auto-updates...

In addition, I found some comments on the list about CentOS 5.3 initrd images coming with scsi modules, and thus not working without rebuilding or manually changing to disable scsi.

Therefore I did the following steps to get an HVM VM initially transformed to PV:

1) get a known-good Centos image for Xen, e.g. at http://stacklet.com/downloads/images/centos/5.3
2) make sure that image works for you with pygrub
3) extract kernel, initrd and /lib/modules/
3) make it work with kernel/initrd/parameters provided externally
3a) don't use a wrong option for ramdisk support ;-)
4) add /lib/modules extracted from other image to HVM image
5a) add kernel parameter "console=/dev/tty" to prove it boots up
5b) modify /etc/securetty and /etc/inittab (if not done yet by your distro), see
http://xen.xensource.com/files/xensummit_4/xensummit_linux_console_slides.pdf
6) boot up the HVM VM in paravirtualized mode

Especially 5) caused me some trouble, as without this option in /etc/inittab, the VM just froze before bringing the login prompt.

This is how far I got in a few hours tonight, but now the previously automatically launching X server does not start. Well, but I'm getting closer.

Open question:
- how to get a Centos 32bit Xen DomU kernel on a 64bit host via repositories?

Ultimatively, it will probably be best to use pygrub and do the kernel management from inside the VM (this will also be easier when thinking about /lib/modules). But at least for my VM, the harddisk layout does not work with pygrup (yet).

Regards,
Martin

Jeff Sturm wrote:
-----Original Message-----
From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-users-
bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Martin Troester
Sent: Tuesday, September 22, 2009 4:17 PM
To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Creating a paravirtualized guest with Xen
3.4.1 andCentos
5.3 (64bit)

Now I'll find out if I can get my original problem solved, migrate the
existing fully virtualized system to a paravirtualizded kernel. Let's
see...

It's not exactly the same, but I have done physical-to-paravirt
migrations on CentOS 5.2 with little effort.  It's probably easiest if
you install kernel-xen packages before you migrate:

1) yum install kernel-xen
2) shutdown
3) copy disk images to dom0
4) create domU config
5) start domU

Afterwards you can use either pygrub or kernel/ramdisk, whichever you
prefer.

-Jeff





_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users

<Prev in Thread] Current Thread [Next in Thread>