Well I just want to understand the exact step by step process of building a tile server from package

Question

http://switch2osm.org/serving-tiles/building-a-tile-server-from-packages/ The above link explains the process but some queries. How does mapnik know what database? How does renderd contact mapnik? All in all please give some link or explain the process. My main problem is that i am getting

ma@DC050:/var/run/renderd$ /usr/bin/render_list -a --socket=/var/run/renderd/renderd.sock Rendering client Planet file updated at Wed May 29 16:13:27 2013 Starting 1 rendering threads Rendering all tiles from zoom 0 to zoom 18 Rendering all tiles for zoom 0 from (0, 0) to (0, 0) Rendering all tiles for zoom 1 from (0, 0) to (1, 1) Rendering all tiles for zoom 2 from (0, 0) to (3, 3) Rendering all tiles for zoom 3 from (0, 0) to (7, 7) Rendering all tiles for zoom 4 from (0, 0) to (15, 15) Rendering all tiles for zoom 5 from (0, 0) to (31, 31) Rendering all tiles for zoom 6 from (0, 0) to (63, 63) socket connect failed for: /var/run/renderd/renderd.sock

on running the above. And I don't understand a bit how all this works some good link on the architecture is most welcome. Please explain it.

The renderd.sock file is not present at the given directory. I did not tamper with it No instance of the process is running. Please help

Answer 1

The database name is specified in the stylesheet (the XML file) that you give to renderd which tells it how to render the data. Each layer listed in the stylesheet details the source of the data for that layer, which in the case of a postgis layer, includes the database name.

There is no need to renderd to "contact mapnik" because renderd is linked against mapnik, so it just calls functions in libmapnik to ask mapnik to do things.

As to your specific problem, either renderd is not running or you have not configured it to listen on the right socket, or have not told render_list to connect to the right socket.