I have a few services on my family server (say, Gitea, Grafana, finance tracking app etc.). I'd like to have a SSO but also limit which users can use which services (e.g. my significant other can use Grafana but no Gitea).
Is integrating above services with Keycloak enough? Or would I need another components? Or maybe I've got it wrong and should reconsider the architecture?
The biggest hurdle I see is do all of your apps support SAML or OAuth/OIDC for authentication/authorization? The SSO tax is a real thing.
In simplest setup (non-HA, local user database), you would create users inside Keycloak, assign them to different groups, then create applications (which handle configuration for individual applications like grafana and gitea) and create rules that specify that only users that belong to specific group can login to specific application.
You can also allow linking multiple external SSOs this way to single keycloak identity, and even include login through kerberos5 or client certificates.