Is it safe to remove debconf cache files in isar system

[Venkat...@toshiba-tsip.com]

Hi,

I am working to fix some reproducible build failures in isar system, as part of this I wanted to know some ideas to fix it.

I am checking the reproducible failures as below:
$ cd isar
$ . isar-init-build-env build1 && bitbake mc:qemuamd64-buster-tgz:isar-image-base
$ . isar-init-build-env build2 && bitbake mc:qemuamd64-buster-tgz:isar-image-base
$ mkdir -p rootfs1 rootfs2
$ tar -xzvf ./build1/tmp/deploy/images/qemuamd64/isar-image-base-debian-buster-qemuamd64.tar.gz -C ./rootfs1/
$ tar -xzvf ./build2/tmp/deploy/images/qemuamd64/isar-image-base-debian-buster-qemuamd64.tar.gz -C ./rootfs2/
$ rsync -nrclv ./rootfs1/ ./rootfs2/ > difference.txt

Below is one reproducible problem I picked:
In debconf db file the contents were different after two subsequent builds,

Part of the debconf db file where the difference is found (/var/cache/debconf/config.dat)
Build1:
Name: ucf/changeprompt
Template: ucf/changeprompt
Value: keep_current
Owners: ucf
Variables:
BASENAME = locale.nopurge
FILE = /etc/locale.nopurge
NEW = /etc/locale.nopurge.29308

Build2:
Name: ucf/changeprompt
Template: ucf/changeprompt
Value: keep_current
Owners: ucf
Variables:
BASENAME = locale.nopurge
FILE = /etc/locale.nopurge
NEW = /etc/locale.nopurge.19132

The probable solution I am thinking of is:
1. remove the debconf cache files (rm -f /var/cache/debconf/*)
2. Fix the debconf in such a way it generates same package configuration on every build

The first solution is easy, but I am worried if those package configuration files maybe required in future when the package is updating
The second solution would need more investigation at debconf package side.

Any ideas or suggestion would be very grateful.

Thanks,
Venkata.

[Anton Mikanovich]

Because both questions are not really Isar-related, but more
Debian-related, maybe it's better to duplicate them on
debia...@lists.debian.org ?

--
Anton Mikanovich
Promwad Ltd.
External service provider of ilbers GmbH
Maria-Merian-Str. 8
85521 Ottobrunn, Germany
+49 (89) 122 67 24-0
Commercial register Munich, HRB 214197
General Manager: Baurzhan Ismagulov

[Venkat...@toshiba-tsip.com]

Hi,

Resending this question in cip-dev mailing list

Thanks,
Venkata.

[Baurzhan Ismagulov]

On Mon, Feb 14, 2022 at 07:35:19PM +0000, Venkat...@toshiba-tsip.com wrote:
> >I am working to fix some reproducible build failures in isar system, as part of
> >this I wanted to know some ideas to fix it.

...

> >Part of the debconf db file where the difference is found
> >(/var/cache/debconf/config.dat)
> >Build1:

...
> > NEW = /etc/locale.nopurge.29308
> >
> >Build2:
...

> > NEW = /etc/locale.nopurge.19132
> >
> >The probable solution I am thinking of is:
> >1. remove the debconf cache files (rm -f /var/cache/debconf/*)
> >2. Fix the debconf in such a way it generates same package configuration on every build

For (1), https://debiananwenderhandbuch.de/debconf.html suggests that those may
be deleted, but questions would be asked during later package updates. If this
is important, maybe it could be workarounded by unattended installation.

(2) would be for sure a better approach. Debian does have a reproducible build
group and might be interested in that. That said, till now I've seen the effort
directed at reproducible packages, not a reproducible installation.

I think debconf people are the best who could answer this. If you don't like
debian-user, you may want to ask at
https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/reproducible-builds .

With kind regards,
Baurzhan.