I am in the process of upgrading our 3 nodes ES 6.7 cluster to Opensearch 2.x. I performed a rolling upgrade from 6.7 to 6.8 and 6.8 to 7.10.2. The upgrade went well and all the indices and cluster looks good. After I upgrade from 7.10.2 to Opensearch 2.x, Openearch is failing with index compatibility error
The index [[logstash-index-000098/ka-F8tMiS-qJh8OBbv4pRA]] was created with version [6.7.0] but the minimum compatible version is OpenSearch 1.0.0 (or Elasticsearch 7.0.0). It should be re-indexed in OpenSearch 1.x (or Elasticsearch 7.x) before upgrading to 2.1.0
As per ES and Opensearch documentation, the indices created in 6.7 should support without any breaking changes from 6.7 to opensearch 2.x
We cannot effort to re-index data, this has to be a rolling upgrade. Is there a way to get around it without reindexing?