Worse, there's no clean install option from within the installer itself. To do any install, you need to boot the Mac with Mac OS X 10.6.8 Snow Leopard or Mac OS X 10.7 Lion from a volume (hard disk, partition, or USB flash drive) and run the installer from that boot drive. To do a clean install, you need two volumes: one to boot from, one to install onto.
Apple has streamlined the server configuration process from previous versions, with fewer screens asking questions and more done automatically. The installer is smarter as well. If you tell the setup assistant to create an Open Directory master, it will do that as well and DNS for the server's IP address if it doesn't find it on the network or the Internet.
That's pretty nice, particularly if you don't know what DNS is. Unfortunately, if you do know what DNS is, the Server application -- now the only management tool installed with Lion Server -- won't show you the DNS configuration is. It provides no way to edit settings for DNS, DHCP, Open Directory, and other network services.
The old administration tools that can access to these services -- Server Admin and Workgroup Manager -- are no longer part of Lion Server. Instead, they are available are a separate download -- but not from the Mac App Store, where you get the Lion Server app. You have to go to Apple's support site. Nothing I could find in the installation screens, the help files, or Apple's main Server website even mentions them. To quote Douglas Adams, the tools were "on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying 'Beware of the leopard.'"
Lion Server's many missing services
Once you locate and download the Server Admin tool, experienced Mac OS X Server administrators will notice it's a much thinner tool than it used to be. Roughly half the services that used to be there are missing. Most user-based services, such as file sharing, calendaring, and Web services, have been moved to the simple Server application. Others, such as QuickTime Streaming Server, have been completely removed.
One of the more significant feature rollbacks comes in reduced support for Windows clients. For years, Mac OS X Server's LDAP-based Open Directory had the ability to function as a primary domain controller (PDC) to support Windows clients. The PDC provided Windows clients with single sign-on authentication, and for those who work on both platforms, it gave users access to the same accounts and server-based home folders from their Windows PCs as well as their Macs. In Lion Server, Windows clients still have access to file sharing, but are now second-class clients.
On the flip side, Lion Server retains Open Directory integration with Active Directory. Mac clients can still bind to Active Directory using the "golden triangle" configuration, where Mac OS X Server and Open Directory bind to Active Directory.
Another service that Apple deleted is the print server of previous Mac OS X Server builds. Lion Server contains only the same ability to share printers found in every copy of Mac OS X client for the past five years: the open source Common Unix Printing System (CUPS), which gives Macs the ability to host shared print queues and simple pools of printers but lacks the enterprise features that previous print servers had. For example, Lion Server's CUPS cannot prioritize printers in the pool or set quotas for individual users or printers. And you can't publish printers to Open Directory.