Re: Re[8]: [Xen-devel] Unable to Configure Xen Dom 0 in Jeremy's PVOPS Kernel

Dear All,

I am very puzzled. In investigating the cause of the sudden success of the CentOS 4.7 32-bit PV guest being able to run, I have uninstalled virt-manager and all of its dependencies:

docbook

python-gtk-vnc

xen-libs 3.3.1

scrollkeeper

xen-tools 3.3.1

libvirt 0.4.6

libvirt-python

vm-install 0.3.24

Then I proceeded to "make uninstall" in xen-3.4-testing source tree, which also removed my self compiled Xen Dom 0 pvops enabled kernel, initrd and kernel modules.

After doing the above, I re-installed back the Xen hypervisor, libraries and tools, and also the kernel, initrd, and modules. Then I proceeded to reboot my machine. After rebooting, my CentOS 4.7 32-bit PV guest is still able to start and run!

I am still very puzzled! What causes the PV guest initially cannot start? Then what subsequently causes the PV guest to suddenly be able to start and run???

***scratches head***

Anyway my CentOS 4.7 guest domain is now running. I shall now proceed to virtualize OpenSolaris 2009.06.

Thank you.

Also see screenshots of my CentOS 4.7 PV guest here: http://teo-en-ming-aka-zhang-enming.blogspot.com/2009/07/creating-centos-47-32-bit.html

Mr. Teo En Ming (Zhang Enming) Dip(Mechatronics Engineering) BEng(Hons)(Mechanical Engineering)

Technical Support Engineer

Information Technology Department
Asiasoft Online Pte Ltd
Tampines Central 1 #04-01 Tampines Plaza
Singapore 529541

Republic of Singapore
Mobile Phone: +65-9648-9798
MSN: teoenming@xxxxxxxxxxx

-----Original Message-----
From: "Teo En Ming" <enming.teo@xxxxxxxxxxxxxxx>
To: "Teo En Ming" <enming.teo@xxxxxxxxxxxxxxx>, "Pasi Kärkkäinen" <pasik@xxxxxx>
Cc: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Date: Fri, 24 Jul 2009 22:54:26 +0800
Subject: Re: Re[8]: [Xen-devel] Unable to Configure Xen Dom 0 in Jeremy's PVOPS Kernel

Hi Pasi,

It's very strange. Suddenly my CentOS 4.7 32-bit PV guest is able to start!!! Previously it refuses to start at all.

I think I must have changed something in Dom 0 when I attempted "yast --install virt-manager". This action might have solved the problem. When I tried to install virt-manager, it also tries to install xen-libs-3.3.1 and xen-tools-3.3.1 as dependencies. However, I started off my Xen Dom 0 pvops kernel install with Xen 3.4.1 rc8 branch.

I need to investigate more why suddenly my CentOS 4.7 32-bit PV guest is able to start.

Mr. Teo En Ming (Zhang Enming) Dip(Mechatronics Engineering) BEng(Hons)(Mechanical Engineering)

Technical Support Engineer

Information Technology Department
Asiasoft Online Pte Ltd
Tampines Central 1 #04-01 Tampines Plaza
Singapore 529541

Republic of Singapore
Mobile Phone: +65-9648-9798
MSN: teoenming@xxxxxxxxxxx

-----Original Message-----
From: "Teo En Ming" <enming.teo@xxxxxxxxxxxxxxx>
To: "Pasi Kärkkäinen" <pasik@xxxxxx>
Cc: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Date: Fri, 24 Jul 2009 21:54:00 +0800
Subject: Re: Re[8]: [Xen-devel] Unable to Configure Xen Dom 0 in Jeremy's PVOPS Kernel

Hi Pasi,

I realized that Fedora 10 32-bit anaconda installer does not install PAE kernel after mounting the guest disk image file. I mounted the guest disk image file using losetup and kpartx which adds device nodes to /dev/mapper. I examined the /boot directory after mounting the guest disk image file and found no PAE vmlinuz and initrd.

Still using the mounted Fedora 10 32-bit guest disk image file, I changed root to the guest disk filesystems and attempted to install the PAE kernel. Then I modified menu.lst to boot the PAE kernel. After modifying the grub configuration of the guest domain, I un-mounted the guest filesystem.

I proceeded to boot the F10 32-bit guest, since I changed to PAE kernel. It is able to boot now (since the PAE kernel is xen-aware) but then it complains cannot mount /dev/root. Probably something to do with the PAE initrd file.

Mr. Teo En Ming (Zhang Enming) Dip(Mechatronics Engineering) BEng(Hons)(Mechanical Engineering)

Technical Support Engineer

Information Technology Department
Asiasoft Online Pte Ltd
Tampines Central 1 #04-01 Tampines Plaza
Singapore 529541

Republic of Singapore
Mobile Phone: +65-9648-9798
MSN: teoenming@xxxxxxxxxxx

-----Original Message-----
From: Pasi Kärkkäinen <pasik@xxxxxx>
To: Teo En Ming <enming.teo@xxxxxxxxxxxxxxx>
Cc: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Date: Fri, 24 Jul 2009 16:31:19 +0300
Subject: Re: Re[8]: [Xen-devel] Unable to Configure Xen Dom 0 in Jeremy's PVOPS Kernel

On Fri, Jul 24, 2009 at 08:37:09PM +0800, Teo En Ming wrote:
> Hi
>
> I attempted to install Fedora 10 32-bit PV guest using
> images/pxeboot/vmlinuz-PAE and images/pxeboot/initrd-PAE.img from the F10
> media. The non-PAE kernel could not load the installer. I finished my Fedora
> 10 32-bit PV guest installation but it also cannot boot up after
> installation, same as the CentOS 4.7 PV guest installation.
>

Fedora 10 installer has a bug, as a default it installs non-PAE kernel for
xen domU. You need to use a kickstart script (like this) to fix it:
http://pasik.reaktio.net/fedora/f10-xen-domu-ks.cfg

The important lines being:

-kernel
kernel-PAE

(Fedora 10 and Fedora 11 default kernels are compiled with pv_ops Xen domU
support enabled, so there's no need for separate kernel-xen with these distros).

Fedora 11 doesn't have that installer bug, so it installs right
out-of-the-box as Xen domU.

What's the error you get when you start the guest after installation?
Please paste the "xm log" as text.

I don't have any problems with CentOS 5.3 dom0.

-- Pasi