Opensearch high CPU Utilitization

Opensearch can be scaled both vertically as well as horizontally. It is hard to make recommendations without getting data around your configuration, the data, the usage pattern and looking at performance test results.

Our documentation does have good recommendations around how to size your OpenSearch cluster - https://docs.aws.amazon.com/opensearch-service/latest/developerguide/sizing-domains.html

There is also a Premium Support article and video - https://aws.amazon.com/premiumsupport/knowledge-center/opensearch-scale-up/

One issue might be that you have too many shards per OpenSearch node. It is recommended to have 1.5vCPUs per shard.

As I don't have additional information about your cluster configuration, data size, and index settings, you can check out my latest article on best practices for configuring an OpenSearch cluster for 1 Billion documents: https://dev.to/viktorardelean/unleashing-opensearch-best-practices-for-1-billion-documents-on-aws-2gi9.