Chapter 24. Implementing Federation
Red Hat supports federation using Red Hat Single Sign-on (RH-SSO) or Microsoft Active Directory Federation Services (AD FS) in combination with Red Hat OpenStack Platform (RHOSP).
24.1. Federate with IdM using Red Hat Single Sign-On
You can use Red Hat Single Sign-On (RH-SSO) to federate your IdM users for OpenStack authentication (authN). Federation allows your IdM users to login to the OpenStack Dashboard without revealing their credentials to any OpenStack services. Instead, when Dashboard needs a user’s credentials, it will forward the user to RH-SSO and allow them to enter their IdM credentials there. As a result, RH-SSO asserts back to Dashboard that the user has successfully authenticated, and Dashboard then allows the user to access the project.
24.2. The federation workflow
This section describes how the Identity service (keystone), RH-SSO and IdM interact with each other. Federation in OpenStack uses the concept of Identity Providers and Service Providers:
Identity Provider (IdP) - the service that stores the user accounts. In this case, the user accounts held in IdM, are presented to Keystone using RH-SSO.
Service Provider (SP) - the service that requires authentication from the users in the IdP. In this case, keystone is the service provider that grants Dashboard access to IdM users.
You can configure the Identity service (the SP) to communicate with RH-SSO (the IdP), which is also able to serve as a universal adapter for other IdPs. In this configuration, you can point keystone at RH-SSO, and RH-SSO will forward requests on to the Identity Providers that it supports (known as authentication modules), these currently include IdM and Active Directory. This is done by having the Service Provider (SP) and Identity Provider (IdP) exchange metadata, which each sysadmin then makes a decision to trust. The result is that the IdP can confidently make assertions, and the SP can then receive these assertions.