We have web application where our customers have organization accounts, have ability to create users for organization management.
We want to use Keycloak realms to separate organization users, potentially could be 500+ realms.
Also Realm separation will allow us specify different Identity Providers per organization (some companies has SAML).
Has anybody had production setup with such number of realms? Any problems except Admin Console cold start?
From what I have found it is known issue [KEYCLOAK-4593] Support having large number of realms - Red Hat Issue Tracker and Opened PR to fix admin console KEYCLOAK-6096: Enhance Keycloak Web Admin Console to support a bigger amount of realms by pmentz · Pull Request #8851 · keycloak/keycloak · GitHub
Local benchmarks with PostgreSQL, keycloak 16.1 shown next results
Realms: 5 100 200 250 350
New Realm Creation takes 400ms 1150ms 2000ms 2300ms 3200ms
Master Admin console cold start after realms cache clearing takes 50ms 15sec 54sec 1.4min 2min
No visible effect on Keycloak auth functionality
Other Realm Admin Console works without delays (realm specific admin)