Magento 2 opensearch indexing error

Question

I'm using opensearch, when I'm trying to reindex 'catalogsearch_fulltext', I'm getting error:
{"error":"no handler found for uri [/khmagento2_product_1_v2/document/_mapping] and method [PUT]"}'

Here is the result of:
curl -u admin:admin -i http://localhost:9200/_cluster/health

{"cluster_name":"khmagento2","status":"yellow","timed_out":false,"number_of_nodes":1,"number_of_data_nodes":1,"discovered_master":true,"discovered_cluster_manager":true,"active_primary_shards":14,"active_shards":14,"relocating_shards":0,"initializing_shards":0,"unassigned_shards":12,"delayed_unassigned_shards":0,"number_of_pending_tasks":0,"number_of_in_flight_fetch":0,"task_max_waiting_in_queue_millis":0,"active_shards_percent_as_number":53.84615384615385}

in magento configuration:

Answer 1

Downgrade to Opensearch 1.3.6 and it will work. You will have to delete the old data from /var/lib/opensearch otherwise opensearch won't start, it will throw exceptions/segfaults.