Re: OSTree in debian

[Paul van Tilburg <paul luon net>]

Hello Agustin,

On Thu, Oct 05, 2017 at 08:45:40PM -0300, Agustin Henze wrote:
> Hello, I'd like to build a bootable rootfs using debian packages. I've reading
> the documentation but it lacks a lot of details about how to generate the grub
> entries or how to make it work correctly at least and how to generate a proper
> initramfs as well.

We use OSTree to deploy and upgrade a couple of thousand of systems
using Ubuntu, but I don't think there is much of a difference with
Debian in this case.
I feel where you're coming from!  To get started still entails a bit of a
steep learning curve because everything is new, the way of working is
different and as you mentioned how to get to a first working system is
not that easy and not that well-documentated at the moment.
It is also one of the reasons I replied.  I think it could be useful
to inventarise where the going gets tough.  In the process of trying out
the system we made some modifications to get everything to work which
were (are) unfortunately undocumenated, but I'm trying to retrace them.

> I've found deb-ostree-builder and gave a try, I could build a rootfs after
> building my own config with some different hooks. Then I've tried with
> `create_deployment` and it seems to be using a different grub or at least a
> module called `blscfg` that is not in upstream.

We currently carry Fedora's patch on grub2 that includes blscfg support [1].
However, which switched to booting with systemd-boot which is much easier
and has native BLS support.

Our system images are built with debootstrap or exported from Docker
images and put through a mangle script that:
* prepares the kernel + initrd with checksum in /boot
* moves /etc to /usr
* takes care of splitting the passwd and group files
* removes dirs like /dev, /run, /var
* cleans up /usr/etc/machne-id
* prepares some OSTree dirs by using systemd-tmpfiles.d
* sets up sysmlinks for /media, /root, /home and /ostree

> As far I can see the ostree
> package for debian has stripped out[0] the grub generator, dracut stuff and
> systemd stuff among others. I've tried building this package called ostree-boot
> and it doesn't work at all and I can't find any documentation about it :(.

We rebuild the OSTree package with ostree-boot enabled. AFAIK we do not make
any modifications and we indeed use dracut instead of initramfs in our
system images.

I hope this helps.

Kind regards,
Paul van Tilburg

1: 
http://pkgs.fedoraproject.org/cgit/rpms/grub2.git/tree/0460-blscfg-add-blscfg-module-to-parse-Boot-Loader-Specif.patch?h=f20

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