▻https://www.mediawiki.org/wiki/Maps
The maps project aims to build cartography technologies for all #Wikimedia projects, at a scale sufficient for their widespread usage.
The production maps cluster (See also on Wikitech) is in development by the WMF Discovery team. The implementation has various components including:
– #Kartotherian Github (primary) / Gerrit (mirror) - a server capable of providing #map #tiles in #vector (pbf) or raster (png) formats, as well as #static_map snapshots of any size for a given location.
– Tilerator Github (primary) / Gerrit (mirror) – a distributed backend tile generation service with a jobque
– A flexible sources system to set up the needed storage and processing pipeline
A version of the tile server is now in operation at maps.wikimedia.org.
– It serves tiles at URLs such as
(bitmap) or …/791.json (OSM data – waterways, roads, place labels, etc.).
– It can scale images for the high-DPI devices – e.g. 1.5x, 2x, etc …/791@1.3x.png
– It can provide static maps with a given size and scaling, e.g. 
Kartotherian - OpenStreetMap Wiki
▻http://wiki.openstreetmap.org/wiki/Kartotherian
Kartotherian is a vector tile server based on open-source Mapbox stack, developed by Wikimedia Foundation for use on Wikipedia. It is horizontally scalable and designed for high loads.
Architecture
Kartotherian is a set of 3 services:
– Kartotherian - tile server itself.
– Tilerator - tile rendering queue.
– Tilerator-UI (optional) - UI for issuing commands to Tilerator.
While Kartotherian can be configured to generate tiles on the fly straight from PostgreSQL, this is intended for development use only and the main mode of operation is to convert vector tiles generated by Tilerator into whatever user-requested format. An HTTP cache such as Varnish is recommended for reducing load on Kartotherian.
