Migrate from rollover aliases to data streams

[Julien_HENRY]

Hi,

I'm just discovering the new data stream concept in Elastic Cloud 7.9.2.
We are ingesting time based documents, so this seems the perfect fit.

Previously, we were using rollover_alias.

I have created the data stream, and I would like to do a smooth transition from the old "way".

Let say my previous configuration was:

PUT _template/old_template
{
  "index_patterns": ["my-index-*"],                 
  "settings": {
    "index.lifecycle.name": "old_policy",      
    "index.lifecycle.rollover_alias": "my-document-writer"
  },
  "aliases": {
    "search-all": {}
  }
}

PUT %3Cmy-index-%7Bnow%2Fd%7D-000001%3E
{
  "aliases": {
    "my-document-writer": {
      "is_write_index": true
    },
    "search-all"
  }
}

So basically all my clients are configured to POST new documents to the my-document-writer alias.

How can I change the destination to be the data stream without changing all my clients? My idea was to atomically change the my-document-writer alias to "target" the data stream, but documentation says that

You cannot add data streams to an index alias.

Any suggestion?