Le Fri, May 11, 2012 at 04:17:39PM +0100, Ian Campbell a écrit : > > Can I just check I understand the motivation for this script properly. > > There are two ways of setting up the disk for a VM. > > The first is the "whole disk" scheme. In this configuration the VM > configuration contains the entire "xvda" which contains a partition > table in the usual way. In this configuration either grub-legacy or > grub-pc can be installed and "grub-install /dev/xvda" does the right > thing including setting up the MBR. This is useful because you can flip > quite easily from PV to HVM just by changing the VM config and > rebooting. (This is the setup I generally use myself, so I'm mostly > familiar with it) > > The second scheme is the "split partitions" scheme. In this > configuration the VM config contains "xvda1" and "xvda2" etc which > appear to the guest OS as partitions but critically there is no overall > "xvda" and therefore no partition table. This means that "grub-install" > cannot work. This is the configuration which EC2 etc use and therefore > this update-grub variant is necessary. > > Is that right?
Exactly. When installing Debian on a EC2 volume with Debian Installer, the partition is a "whole disk", completely usable by grub. But that means that when the newly prepared Debian system is booted, it is a root partition, which is "split partitions" in the Amazon cloud and grub hooks will fail when installing a new kernel (I did not have time to triplecheck). Perhaps that could be solved by making the hooks checking for the availability of a MBR before running grub, but the grub packages are quite critical, and I am not sure how this additional complexity would be welcome. In addition there is a second problem. Pv-grub needs a menu.lst file that is made by GRUB 1. But Debian's GRUB 1 package is in maintainance-only mode, I do not know what are the plans to remove it eventually, but once GRUB 2 can replace it in all cases, this may happen. So it is probably better to have a menu.lst-builder script for pv-grub maintained somewhere else. The pkg-xen project on Alioth is a good idea indeed. Or maybe pv-grub could be extended to parse menu.cfg files ? But I do not know how long it would take for this new function to propagate to Amazon. Have a nice day, -- Charles Plessy Tsurumi, Kanagawa, Japan -- To UNSUBSCRIBE, email to debian-wnpp-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20120524000807.gc15...@falafel.plessy.net
