Currently, hiera variables can be set per-project on wikitech for example at https://wikitech.wikimedia.org/wiki/Hiera:Tools. However, AFAICS, it is not possible to set variables differently for each host.

For the most part, on projects with local puppet masters this can be worked around by amending hieradata/labs/*. But it would be very nice if that wasn't necessary and there would be a 1:1 "mapping" between:

• hieradata/labs/$project/common.yaml = https://wikitech.wikimedia.org/wiki/Hiera:$project
• hieradata/labs/$project/host/$hostname.yaml = https://wikitech.wikimedia.org/wiki/Hiera:$project/$hostname

(with the wikitech configuration taking precedence).