First you'll need an initialized cosa workdir:
cosa init https://github.com/coreos/fedora-coreos-config
Now, we need the previous build data: coreos/coreos-assembler#1013
But we can hand-roll that too:
$ buildid=31.20191219.20.1
$ mkdir -p builds/${buildid}/x86_64
$ (cd builds/${buildid}/x86_64 && curl -LO https://builds.coreos.fedoraproject.org/prod/streams/testing-devel/builds/${buildid}/x86_64/meta.json)
Extend with the new region:
$ cosa aws-replicate --build "${buildid}" --region me-south-1
And save the updated meta.json
:
$ cosa buildupload --build "${buildid}" s3://...
That's totally fine! It's intentional that the "cosa schema" is just some JSON and files stored in S3, not much magic to it.