changeip to check the status of your server no longer returns trustable results. The tool can be used to correct the identity of the server but you need to know the syntax of the tool and get your values in the right place. For example:
sudo /Applications/Server.app/Contents/ServerRoot/usr/sbin/changeip 172.16.0.45 172.16.0.45 Carbons-Mac-mini.local wave.carbontechnologies.com
In Yosemite, the best way to confirm that everything is proper is to use Server.app. First, ensure that DNS is setup and, as Jeffrey documented above, use your resolution tools to confirm (host, nslookup, dig). Once you are confident the server knows its own identity, open Server.app and select the server from the sidebar. On the Overview tab, look at the Hostname section. If the value is not a proper DNS name, press the Edit button and complete the assistant. This is the equivalent of changeip in Yosemite.
My guess is Apple is trying to further simplify their toolset. This means reducing the need to use tools other than Server.app. They have a long way to go, but but finally putting a working name validator into Server.app, they are addressing a very early need of server admins.
Reid
Apple Consultants Network
Author "Yosemite Server – Foundation Services" :: Exclusively available in Apple's iBooks Store
Author "Mavericks Server – Foundation Services" :: Exclusively available in Apple's iBooks Store
Author "Mavericks Server – Control and Collaboration" :: Exclusively available in Apple's iBooks Store