[ubuntu-cloud] How are Ubuntu images built?

Spike Spiegel fsmlab at gmail.com
Sat Nov 20 10:00:45 GMT 2010

On Sat, Nov 20, 2010 at 1:16 AM, Scott Moser <smoser at ubuntu.com> wrote:
> vm-builder does it more like:
>  * create a root filesystem
>  * install certain packages in it (cloud-init, legacy-grub-ec2,
>   openssh-server... the 'uec' task)
>  * copy root filesystem to loopback image

how is this image created? like a dd if=/dev/zero ... ? Does it get
partitioned? What's with this piece of code that I've found in several
places (this comes from build-ec-image , automate-ec2-builds):
if [ "${arch}" = "i386" ]; then
                printf "%s\n%s\n%s\n" "root ${size} a1" \
                        "/mnt 1 a2" "swap 1024 a3"
                printf "%s\n%s\n" "root ${size} a1" "/mnt 1 b"

why x86_64 has no swap? and the /mnt is only to mount ephemeral and
get access to the keypair?

>  * run some "fixups" (vmbuilder-uec-ec2-fixes)
> I'm not sure about hwclock.

I just mentioned because I noticed this in the ec2 plugin:


> grub2 installation wont help you with the
> pv-grub kernel, as it reads only a grub1 (0.97) menu.lst file.
> The UEC images have both grub2 and legacy-grub-ec2 installed so that they
> can use either loader (grub2 on kvm or hvm or virtual-box ...).

uhm, this part still confuses me, but I'll pick it up in the other
thread, in fact maybe we should even consolidate them for the sake of

once again, thanks a lot for all your time and help,


"Behind every great man there's a great backpack" - B.

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