[ubuntu-cloud] How are Ubuntu images built?

Scott Moser smoser at ubuntu.com
Sat Nov 20 01:16:46 GMT 2010

On Fri, 19 Nov 2010, Spike Spiegel wrote:

> vmbuilder is exactly what I need and have been tried to use, except
> that the one shipped with maverick is clearly broken and couldn't find
> a working one until you pointed out yours (thanks again!). But it's
> true tho that I'd like to also understand this process a bit more in
> details. It seems that the required tasks boil down to:
> * create an image file
> * partition it
> * debootstrap $distro
> * install suitable kernel
> * configure/install grub2
> * fix up hosts/network
> * fix up fstab
> * disable hwclock

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
 * run some "fixups" (vmbuilder-uec-ec2-fixes)

I'm not sure about hwclock.  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 ...).

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