For FORM authentication, more support is required as the browser/client is not part of the authentication implementation. Jetty support SSOs for FORM authentication by defining a SSORealm interface. UserRealm implementations that also implement the SSORealm interface are used by the FormAuthenticator in SSO mode.
The HashUserRealm provided with Jetty implements SSORealm by delegating to a configured SSORealm implementation. The HashSSORealm implementation is provided to support basic non-distributed SSO functionality.
The sample configuration file demoSSO.xml runs the Jetty demo twice in SSO mode at /jetty0 and /jetty1. Logging into one instance will enable SSO authentication in the other.