Based on the information provided in the extracts: 1. Ory Kratos requires a production-grade database such as PostgreSQL, MySQL, or CockroachDB [source](https://www.ory.sh/docs/kratos/guides/production). However, it's not explicitly mentioned whether you can share the app DB for Kratos too. It's generally recommended to keep your application database separate from your user management service for security and scalability reasons. 2. Ory Kratos can be run on any operating system and on most processors. It can be run as a single, static binary or as a Docker image [source](https://www.ory.sh/docs/kratos/ory-kratos-intro). Therefore, you should be able to use a dockerized PostgreSQL or CockroachDB within your cluster. However, it's important to note that Ory Kratos does not support multi-tenancy in a self-hosted setup due to data, scalability, and operational complexity [source](https://www.ory.sh/docs/kratos/guides/multi-tenancy-multitenant). For more specific recommendations, you might want to refer to the official Ory documentation or reach out to the Ory community.