Re: Minimizing isar-image-base

[Alexander Smirnov <asmirnov@ilbers.de>]

Jan Kiszka <jan.kiszka@siemens.com> 22 августа 2018 г. 22:52:32 написал:

> On 2018-08-22 16:37, [ext] Jan Kiszka wrote:
>>>> - Why do we pre-install dbus?
>>>
>>> Again, IIRC, without dbus there was dirty boot log in QEMU, some
>>> services failed to start.
>>
>> I'll recheck that with stretch.
>
> Removed it, but I'm not seeing any error messages nor does systemctl
> report failed services.
> Maybe the bug was solved in stretch. Christian,
> you said there is a harder dependency in reality than the "recommends"
> as Debian declares now. Any comments on this?
>
> If it is really no longer needed, we could push the dbus dependency into
> debian-jessie.conf. Is raspbian-jessie on systemd as well? Then there as
> well.

One another thing changed since that time - migration from multistrap to 
debootstrap. Probably this could be the reason.

Alex

>
>>
>>>
>>>> - Can we make apt optional? Installing it as transient package by
>>>>   default, e.g. What would happen if a downstream image then puts it
>>>>   into PREINSTALL again? Should we filter IMAGE_TRANSIENT_PACKAGES
>>>>   against IMAGE_PREINSTALL?
>>>
>>> I could suppose how apt went to isar-image-base recipe, initially it
>>> was a copy of buildchroot one. So nobody actually cares about the list
>>> of packages, there was only one requirement - no error and warnings
>>> during image boot in QEMU.
>>>
>>> In buildchroot apt is needed to populate the dependencies.
>>>
>>> With current Isar implementation the apt is a must package for image.
>>> Let me explain why. Below is the whole chain to generate image:
>>>
>>> 1. At first, isar-debootstrap is called. This recipe fetches minimal
>>> *pure* Debian suite for specified architecture. It's stored in
>>> tmp/deploy folder.
>>> 2. Image generation is started from copying this pre-fetched suite to
>>> work folder.
>>> 3. Then you chroot to this *pure* minimal suite.
>>> 4. And finally all the additional packages in pre-install list are
>>> installed via apt-get.
>>>
>>> So, the only way for current architecture - remove apt in post-build
>>> task.
>>
>> Right, this is what I had in mind. I think we already have the tooling
>> for that, don't we?
>
> We don't. IMAGE_TRANSIENT_PACKAGES is not suited.
>
> Also, apt seems to get installed via debootstrap anyway. We should be
> fine removing it as explicit IMAGE_PREINSTALL entry. I'll propose a patch.
>
> But we will need some explicit purging step that removes it again (and
> possibly more packages) after the image is done. And it should be under
> custom-image control, whether that step is run or not - or what the
> purge list contains. We could also use --exclude of debootstrap but that
> would imply forking the base bootstrap environment because we use the
> same for image and buildchroots so far. Probably not a good idea.
>
> Jan
>
> --
> Siemens AG, Corporate Technology, CT RDA IOT SES-DE
> Corporate Competence Center Embedded Linux