Hi Jan, On Feb 23, 2011, at 16:23 , Jan Kundrát wrote: > 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. I guess that explains why noone else is seeing this problem. Why would I want to run an SL5 Xen VM under an SL5 Xen hypervisor as an HVM instead of a paravirt VM? I agree it should work, though, and I know that it did in the past. > 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. Interesting, I thought it was impossible to run Xen under Xen and that this kind of "recursive virtualization" is an exclusive feature of KVM. >> 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. KVM is readily available on SL5, so this may be a way to solve your actual problem. Best regards, Stephan >> 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 > -- Stephan Wiesand DESY -DV- Platanenenallee 6 15738 Zeuthen, Germany