Hi, Firstly apologies for the cross post but I think this genuinely is of interest to both audiences. I'm subscribed to both lists so no need to CC me. I'm interested in getting d-i to work seamlessly inside a Xen guest domain using the paravirt_ops kernel support for Xen in 2.6.24+ (currently only available in the kernel svn trunk snapshots builds I think). At the moment the normal way to deploy a Debian VM seems to be to use debootstrap. However this has short comings WRT non-Debian domain0, plus the installer way of doing things is more more familiar to many (well, IMHO) and d-i sets up a bunch of stuff which otherwise has to be done manually (packages such as xen-tools help with that bit though). Making d-i available for PV use also allows the virtual machines to appear more like native machines to an admin and the installed result is more like a regular Debian install. FWIW several other distros support using their installer in a PV context (Fedora, RHEL and SLES that I'm aware of). I've built myself a Xen-enabled netboot image and didn't come across any major issues or show-stoppers, just small niggles, such as allowing grub to run successfully inside a PV domain (patches in: grub #456776, grub-pc #456777 and grub-installer #456784). The only real stumbling block at the moment is the kernel. Most distributions (including Debian) only support PAE Xen on i386 but the d-i kernel is non-PAE. I don't imagine there would be much enthusiasm about enabling PAE in d-i so I think at least one new d-i flavour would be required here. It would be reasonably easy to create -xen-686 udebs (in fact I did for my testing) and tweak d-i to select a -xen kernel package image as appropriate during install, however I think I have a better idea ;-)... I'd like to propose enabling Xen guest support in all the native i?86 kernel images (and eventually amd64 too), or at least in the -686-bigmem kernel. Since paravirt ops is already enabled in all kernels (for KVM and lguest) there is only minimal additional overhead to enabling Xen. As a nice bonus this would also allow the separate -xen flavour kernels to be removed/deprecated which seems like a good thing in the paravirt_ops based world. Given a suitable kernel it would then be possible to add a -bigmem flavour of d-i. That would give us installer images which support native, Xen, KVM and lguest via paravirt_ops both PAE and non-PAE allowing Debian to be installed as a guest on a wide variety of domain0 distributions. So, what do the kernel folks think about enabling Xen guest support in all kernels where it is available and getting rid of the -xen specific variants? I've got a massive (mainly due to lots of deletion) patch against SVN which does just that, if there is interest I'll work out the kinks and file it as a wishlist bug. And what do the d-i folks think about an additional d-i flavour for -686-bigmem? Initially I'd propose just building a netboot type image. I don't think cdrom or floppy are all that critical in a virtualised scenario, although CD support would be a nice to have, I suppose. I've got some hacky patches but they would likely need change depending on the decision made WRT the kernel. For those who are interested the only other issues I've come across while playing with this is the need to run a getty on /dev/hvc0 and breakage with update-grub with the latest xen enabled kernels due to the CONFIG_* change since 2.6.18. Seems like both should be easy enough to fix... Cheers, Ian. -- Ian Campbell There has been a little distress selling on the stock exchange. -- Thomas W. Lamont, October 29, 1929 (Black Tuesday)
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