grub should be pre-installed on images

[Dimitri John Ledkov]

given that grub are now co-installable by default, shouldn't they be preinstalled in the squashfs?

it seems like grub-efi-amd64-bin & signed are not in the squashfs.

I guess that affects all of ubiquity & subiquity images.

[Steve Langasek (vorlon)]

Pros:
 - installing them in the squashfs is faster than installing them at build time
 - if we believe they should always be installed, it simplifies the installer logic
   - except that we're also converging on a single installer code base, so it doesn't simplify things too much to have it in livecd-rootfs instead of in curtin (and curtin still has to trigger grub-install to the target disks, either by replaying the package postinsts on the target or by manually calling grub-install)

Cons:
 - this moves us farther away from being able to converge the server squashfs as used by subiquity with the lxd squashfs published by cloud images. (we don't currently have a path forward for how to build this once and consume it in both places, but nevertheless I don't like that we currently build it twice.)

[Michael Hudson-Doyle (mwhudson)]

On Tue, 4 Jun 2019 at 17:25, Steve Langasek <email address hidden>
wrote:

> Pros:
> - installing them in the squashfs is faster than installing them at build
> time
> - if we believe they should always be installed, it simplifies the
> installer logic
> - except that we're also converging on a single installer code base, so
> it doesn't simplify things too much to have it in livecd-rootfs instead of
> in curtin (and curtin still has to trigger grub-install to the target
> disks, either by replaying the package postinsts on the target or by
> manually calling grub-install)
>
> Cons:
> - this moves us farther away from being able to converge the server
> squashfs as used by subiquity with the lxd squashfs published by cloud
> images. (we don't currently have a path forward for how to build this once
> and consume it in both places, but nevertheless I don't like that we
> currently build it twice.)
>

I guess we could approach this with layers / seeds? So you'd have one layer
("server-core" "server-base" "server-container"? all the names you might
use for this are horribly overloaded) that would be the lxd image, and
another layer ("server-machine"?) that would contain things you need for
installing a bootable system, so grub-pc, grub-efi-amd64-bin on amd64,
maybe initramfs stuff and subiquity would install from the server-machine
layer by default.

[Steve Langasek (vorlon)]

Yeah, I suppose we can get away with quite a lot of that. The fixed per-layer disk overhead of each squashfs looks like it's on the order of 4M (/var/lib/dpkg/status + /var/lib/apt/extended_states), which is not large in the grand scheme. And since we know this layer would be used unconditionally for all subiquity install methods it would not make it harder for us to ensure everything remained a tree.