Re: [RFC 0/2] Remove Packages during Postprocessing

[Henning Schild <henning.schild@siemens.com>]

Hi Sundaram,

Am Wed, 21 Sep 2022 22:55:07 -0700 (PDT)
schrieb "'Balasubramanian Sundaram' via isar-users"
<isar-users@googlegroups.com>:

> Hi Team,
> 
> Iam using ISAR build system for imx6 nxp based processor, I need to
> remove some user binaries like perl, shared-mime-info,libx11-6,
> can you please provide steps or which file i need to change to remove
> these binaries in the final .wic.image

If the binaries are in the rootfs they are coming in as
runtime dependency of something. Or maybe the packages have been
explicitly installed by accident.

Removing rdeps is risky, you never know what you might break. So you
should think _really_ _really_ carefully about the reasons to remove
things. Question those reasons several times. Weird legal or security
reasons are better resolved in other ways. Even if one "firmware" works
with forcefully removed rdeps, the next version might break in funny
ways ... or you see the breakage in the field, on a code-path never
seen during testing.

If it is about size i would advise to rather choose a board with bigger
mass storage, a product released today where the firmware barely fits
... is not going to live too long and the hacks will get worse over the
years. Maybe try some sort of filesystem compression instead.

So now that we are clear that it would be a really bad idea ...

You best bet might be to give the patches a try. And give feedback on
how well they worked for you ... or not. Should you be using kas, it is
easy to apply patches to isar and describe all that in a kas-file in
your layer.

regards,
Henning

> Thanks & Regards
> 
> On Tuesday, February 25, 2020 at 11:13:57 AM UTC+5:30 Gylstorff
> Quirin wrote:
> 
> >
> >
> > On 2/24/20 3:24 PM, Henning Schild wrote:  
> > > Hi,
> > > 
> > > my opinion on that is clear. Fix it upstream or live with those
> > > packages. You are either on a distro or fiddle around and tune
> > > everything until you are the only one on the planet testing your
> > > setup. That is Isar vs. yocto ... whoever thinks they _need_ that
> > > should maybe think again. If they need it they can put it into
> > > their own layer or use yocto ;).
> > > I do not think upstream should carry such hacky features unless
> > > we get better reasoning ... Removing "required" packages has the
> > > potential to break your image in funny ways ... that is much more
> > > expensive than a few MB disc space. All affected packages are
> > > likely already cleared and vulnerabilty monitored by someone
> > > else, find that someone and share the cost!
> > > 
> > > Henning  
> >
> > Hi Henning,
> >
> > I understand your concern and I think you are right. But some people
> > already hack the build process in similar ways and this is a way to
> > give them some support.
> >
> > I want to collect the option of community regarding this patch.
> >
> > Quirin
> >  
> > > 
> > > On Fri, 21 Feb 2020 15:53:46 +0100
> > > "Q. Gylstorff" <Quirin.G...@siemens.com> wrote:
> > >   
> > >> From: Quirin Gylstorff <quirin.g...@siemens.com>
> > >>
> > >> Some packages even if the are part of minbase are not necessary
> > >> to run a debian system. Debian has some issues and experiments
> > >> to remove packages from minbase [1]. This feature allows a
> > >> expert user to remove packages from the final image during post
> > >> processing.
> > >>
> > >> The reason for this are e.g. disk usage reduction and reduction
> > >> of the clearing effort.
> > >>
> > >> The method to remove packages in postprocessing is a best-effort
> > >> action.
> > >>
> > >> Another way would be to identify like [1] packages in
> > >> minbase which can be removed without compremising the isar rootfs
> > >> creation and remove them directly after or during bootstrapping.
> > >> If a package is used for a production related feature it should
> > >> be reinstalled.
> > >>
> > >>
> > >> [1]: https://wiki.debian.org/BusterPriorityRequalification
> > >>
> > >> Quirin Gylstorff (2):
> > >> meta/classes: Add remove packages to rootfs postprocessing
> > >> meta-isar/images: Remove gcc-8-base from rootfs
> > >>
> > >> meta-isar/recipes-core/images/isar-image-base.bb | 4 ++++
> > >> meta/classes/image.bbclass | 2 +-
> > >> meta/classes/rootfs.bbclass | 13 +++++++++++++
> > >> 3 files changed, 18 insertions(+), 1 deletion(-)
> > >>  
> > >   
> >
> > -- 
> > Quirin Gylstorff
> >
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