I am trying to implement keycloak as an SSO for my company. I have created two realms, realm A and realm B. I want to use same set of users for both realms ie I need give access to users for both realms. Is it possible to do this in Keycloak?
No that's not possible. Users are always realm specific. The only way would be to keep the users in an external store and integrate this external store via federation (UserStorageSpi) into both realms. But then you'll have to do all user management on the external store, as it is the primary source of your user data.