Currently this can be done via SMW but the interface is something I have never quite figured out. Should have a more yuvi friendly tool!
|Open||None||T189531 All Wikimedia developer services should use single sign-on|
|Open||None||T161859 Make Wikitech an SUL wiki|
|Open||None||T106123 Extensions needing to be removed from Wikimedia wikis|
|Resolved||Marostegui||T164887 Drop Semantic Database tables from wikitech wikis|
|Resolved||bd808||T53642 Get rid of SemanticMediaWiki/SRF/SF from wikitech.wikimedia.org|
|Resolved||yuvipanda||T103995 Build a simple tool to query which instances have which roles / puppet variables|
Alright. :) By "interface", do you mean the mechanism for storing the data, or for querying it? If it's the latter, one possibly helpful feature is Semantic Forms' Special:RunQuery - it lets you create a form that serves as a GUI for running the specific query you need. You guys might be using that already, though.
https://tools.wmflabs.org/watroles/role/role::puppet::self is a simple version I knocked up in a couple of hours which should do the job well once a couple more things get added to it :) Code at github.com/wikimedia/watroles