Amazon Cognito without using Amazons Elasticsearch Service?


I am wondering if its possible use Amazons Cognito Service with Opendistro. We currently have EC2 instances that are running OpenDistro and we cannot move them over to Amazons Elasticsearch Service. Our goal is to keep our current EC2 instances but add Cognito to them. If this is possible, could someone explain how it is done?

Has anybody done this yet?