The vCenter Single Sign On (SSO) introduced with vSphere 5.1 has been improved in 5.5, reflecting (negative) feedback on the initial release:
- Simplified deployment (single installation model for customers of all sizes)
- Enhanced Microsoft Active Directory integration - The addition of native Active Directory support enables cross-domain authentication with one- and two-way trusts common in multi-domain environments.
- Architecture - Built from the ground up, this architecture removes the requirement of a database and now delivers a multi-master authentication solution with built-in replication and support for multiple tenants.
Granular access control using Active Directory integration for vCenter instances as well as for vSphere hosts existed since vSphere 4.1, so users/admins can be centrally managed using the existing AD infrastructure and assigned roles and right.