On 02/23/11 15:51, Troy Dawson wrote:
> Just because the client kernel is running 2.6.18-238.1.1.el5xen does not
> mean it is trying to be a xen host.  It means that it is running
> paravirtualized.  If your xen machine was setup to be a paravirtualized
> client, then it *has* to continue to run the xen kernel.  You can't just
> switch from the one to the other (as far as I know).

Hi Troy,
the domU has always been a fully virtualized one, as requested by the
builder=hvm stanza given in the configuration file. The disk image
contains everything, from the bootloader and partitions to the kernel,
and the in-the-image-installed Grub is invoked and asks me what kernel
to boot.

When I was speaking about kernel changes, I meant that I have installed
various versions of the kernel RPM inside the domU, one of them being
kernel-2.6.18-194.32.1.el5, other kernel-2.6.18-238.1.1.el5 and yet
another being kernel-xen-2.6.18-238.1.1.el5.

Now, no matter what kernel and Xen versions I choose to run in the dom0,
physical host, I haven't managed to boot the domU using
kernel-2.6.18-238.1.1.el5. I'm always using full virtualization, this
has remained fixed during all tests.

If I pick any of kernel-2.6.18-194.32.1.el5 or
kernel-xen-2.6.18-238.1.1.el5 at the Grub's prompt displayed inside the
vncviewer which I use to access the domU's console, it boots fine. Note
that the kernel-xen package actually boots using the following lines:

title Scientific Linux SL (2.6.18-238.1.1.el5xen)
        root (hd0,0)
        kernel /boot/xen.gz-2.6.18-238.1.1.el5
        module /boot/vmlinuz-2.6.18-238.1.1.el5xen ro root=LABEL=/
        module /boot/initrd-2.6.18-238.1.1.el5xen.img

so that kernel is actually running on top of Xen which itself runs in
the fully virtualized machine, which runs inside Xen on a physical machine.

> When you are running it on Gentoo, you probably set it up to not be
> paravirtualized, so it happily ran the regular kernel.

In fact, the virt-manager run it via kvm, so without any traces of Xen
at all. That particular physical machine has never had Xen on it.

> If you are wondering, I did test the scenario you have.  I currently
> have a xen host running 2.6.18-238.1.1.el5.  Some of it's clients
> are/were running the older kernel, some 2.6.18-238.1.1.el5.  All of them
> are working fine.

I've just updated kernel on another domU instance to the -238, again a
fully virtualized one, and the symptoms are the same, ie. it won't boot
and gets stuck on the serial thing. I suspect that both domUs have been
installed via the same (or at least very similar) kickstart file via PXE.

I guess I can clean up the image and provide it for testing, if you
think it could help debugging this issue. The same applies for the
kickstart file.

Thank you for your help so far, I'm really lost at what I'm doing wrong
here.

With kind regards,
Jan