I have been working on multi-tenant OpenSearch (a.k.a. Open Distro for ElasticSearch) project. This article (https://www.elastic.co/blog/found-multi-tenancy) (from 2015) outlines a few isolation models and the issues you are likely to hit with each. Below I look at two options: one index per tenant and multiple tenants per index with document level security – a feature of OpenSearch.
Provisioning I created a simple single-node Elasticsearch cluster on a t3.small. This is really small but I want to put pressure on the system and see how it scales.