‘m using Keycloak as my IAM solution for my websites. In my application’s database, I populate the user (user id property) with additional information.

I have both on-premise and cloud Keycloak instances, each with the same set of users. Since there’s only one database, I can’t switch between the Keycloak instances because the users have different IDs. I have access to the underlying database of both Keycloak instances.

Is it possible to change the user IDs so that they match across both Keycloak instances?

The only workaround I’ve found so far is to use separate databases, but this is not a viable long-term solution.

Note: Please do not question the architecture of this solution. This is the approach I need to take at this time.