[yocto] minimize size of SW update bundle

[Patrick Ohly]

On Tue, 2017-10-17 at 16:12 +0300, Robert Berger wrote:
> Hi,
> 
> Imagine you have only a limited bandwidth to your devices available
> for 
> SW update. So you would like to minimize what's uploaded (over the
> air) 
> to your devices.
> 
> How would you do this with yocto?
> 
> [1] and [2] might be able to do incremental updates,

Both can indeed do it.

> Like how would you get a diff between two release builds...
> 
> [1] https://wiki.yoctoproject.org/wiki/Meta-swupd

With meta-swupd, set SWUPD_DELTAPACK_VERSIONS to generate binary diffs
against certain older releases. In addition, a single archive gets
created with just the right content for updating from the older
releases to the current one (= better compression, less GET requests).

> [2] https://github.com/advancedtelematic/meta-updater

That's basically OSTree. See https://ostree.readthedocs.io/en/latest/ma
nual/repository-management/#derived-data-static-deltas-and-the-summary-
file for instructions on generating deltas.

-- 
Best Regards, Patrick Ohly

The content of this message is my personal opinion only and although
I am an employee of Intel, the statements I make here in no way
represent Intel's position on the issue, nor am I authorized to speak
on behalf of Intel on this matter.