On Thu, Nov 09, 2006 at 07:47:09PM -0500, Kanwar Ranbir Sandhu wrote: > On Thu, 2006-11-09 at 16:03 +0000, Daniel P. Berrange wrote: > > The solution is fairly simple though - the latest FC5 errata also provides a > > 'kernel-xen' RPM which is PAE enabled. So before upgrading your host, just > > make sure you have done 'yum install kernel-xen' in each of your guests. > > This will let your FC5 guests contonue working on an FC6 host - you can then > > upgrade your guests to FC6 at will. > > I don't understand this. Why does kernel-xen have to be installed in > the guest? Doesn't the guest just use the xen kernel running in dom0? > I'm obviously missing something here. It doesn't *have* to be installed in the guest - that's just way we deal with it in Fedora. The overriding strategy for Xen in Fedora is that we want to make installing, upgrading, managing the operating system in a guest a close to what you do on bare metal as possible[1] - so all your existing Linux knowledge still applies - this makes it easier for people who don't know Xen to get started. Basically the way it works is thus: - In the guest OS a regular rpm install of the kernel-xen is done. So a regular grub config is written to the boot sector of the virtual disk pointing to the kernel inside the image. - When booting the guest from Dom0, we run 'pygrub' which pulls the grub config from the DomU filesystem & uses that to extract the guest kernel to a temporay file /var/lib/xen - The DomU is then booted off the temp file in /var/lib/xen So, yes for the actual boot process the kernel is located in Dom0. The other nice thing about this is that the DomU it self contained - you can move the filesystem image anywhere & no have to worry about carting around a separate kernel image file to go with it. Then again, some people may like to have a single kernel image in the Dom0 whcih they use to boot all their guest images. If you want to manage your guests that way, simply add the 'kernel=/foo/bar/wizz' parameter to the guest config, and remove the pygrub config option. Dan. [1] Other examples.... - using regular Anaconda for installing the DomU rather than fragile install into a chroot shell scripts other distro use. - adding the paravirt framebuffer to Xen so you have a fully graphical console -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=| -- Fedora-xen mailing list Fedora-xen@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-xen