Re: [isar-cip-core][PATCH 0/3] Added support for rootfs-overlay (for development).

[Jan Kiszka <jan.kiszka@siemens.com>]

On 17.02.25 11:00, alexander.heinisch@siemens.com wrote:
> From: Alexander Heinisch <alexander.heinisch@siemens.com>
> 
> Updateable images based on isar-cip-core come with immutable rootfs
> out of the box. During development this oftentimes comes with the penalty
> of having to either rebuild images with additional files, packages aso.
> to accomplish development and debugging tasks or derive from the production
> image in a way that some fundamental features like verity, squashfs, swupdate, aso.
> are not part of such.
> 
> Both cases are far from optimal. With this patch series we want to share
> our attempt to streamline development by staying as close as possible to
> our production image by overlaying the squashfs or erofs based ro filesystem
> with an overlay. To make changes redundant accross reboots, we decided
> to use a persistent storage option in favour of a tmpfs based approach.
> (Although, technically there is no limitation on doing so)
> 
> Keep in mind, support for the root overlay is thought as a development
> feature! Thus, it is not thought for production, as it invalidates many
> of the properties we have from ro-filesystems. Also, keep in mind that
> changes on the overlay may partially hide updates or lead to "unexpected"
> results after applying updates.
> 
> Alexander Heinisch (3):
>   Removed "ro" option from read-only-rootfs's fstab.
>   Fix return value handling on filesystem check
>   Added support for rootfs-overlay.
> 
>  classes/read-only-rootfs.bbclass              |  2 +-
>  .../files/local-bottom.tmpl                   | 97 ++++++++++++++++---
>  .../initramfs-overlay-hook_0.3.bb             |  2 +-
>  3 files changed, 87 insertions(+), 14 deletions(-)
> 

Thanks, already applied patches 1 and 2. 3 is still under review and
will need at least some rewording.

Jan

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