I'd like to centralize all authentication on my network using something like an LDAP server. Clients consist of Windows and Linux servers.
I'm looking to manage authentication for virtualized servers in a multi-tenant situation. Thousands of VMs with hundreds of organizations. Skillset leans towards Linux, but I do have experience with Windows. It's only authentication I'm looking for. I do want something that can tie into dual factor auth later on. I use other tools for configuration management. Authorization is handled by the individual virtual servers and left to the tenants.
Please share your experiences with centralized auth!