EC2 HVM images now working

Hi all, great news!

I finally managed to get HVM images working on EC2!

Currently they are booted with extlinux as I am still having some trouble installing grub.

There is a sample manifest in the build-debian-cloud manifest folder you can try out.

So far I have only tried with an unpartitioned volume.

However, this is not all:

Booting from GPT partitioned volumes on virtualbox is now also possible, both with grub and extlinux! I would hazard a guess and say that both MSDOS (renamed from MBR to avoid confusion) and GPT partitioned volumes should work on HVM as well (I don't know about GPT on PVM though, haven't tried).

On virtualbox this means that that you can combine partitioning (none, msdos, gpt) with booting (extlinux, grub) in any way you like (except for grub + no partitions, it's prone to breakage).

I will try to test more combinations in the future, here is a small table of how far I've come:

boot\type none msdos gpt

vbox --------------------

grub O X X

ext X X X

ebs ---------------------

pvgrub X X ?

grub O ? ?

ext X ? ?

s3 ----------------------

pvgrub X ? ?

grub O ? ?

ext ? ? ?

X means "working", O means "not working" and ? means "not tested".

grub+ext of course only makes sense on HVM instances while pvgrub is for PVM instances.

I have also made the partitions sizing more finely adjustable. For GPT this means that the grub_legacy partition is exactly 1007KiB, prepending that with the GPT table header you get a nicely aligned 1MiB offset for the next partition.

Also: Whatever extra space is required for GPT, post-MBR gap or grub partition will now be subtracted from the first partition. This means there is no longer any need to remember how much space you exactly need to subtract from your root volume to hit 1 gigabyte. You just specify "root": "1GiB".

Anders