As the original thread Zammad 6: Opensearch instead of Elasticsearch - Zammad 6 refuses - #13 by sebix has been closed by Zammad, I guess this is now the continuation.
We are running our Zammad installation with OpenSearch 2.19.1 currently, so I can confirm this combination works.
I just updated my test environment to OpenSearch 3 (GitHub - sebix/zammad-docker-compose at opensearch and GitHub - sebix/zammad at opensearch), but the workflow ran into some error (pull access denied for zammad-local 
) that I can’t solve ad-hoc.
We used that same environment initially to verify the compatibility of Zammad with OpenSearch 2, so in principle, that method should work.
Referring to an open question in the old thread:
My question (July 2023) in the OpenSearch forum is unanswered to date: Will the ingest-attachment plugin become a module like in ES? - OpenSearch - OpenSearch