renderd not rendering

Question

I followed the instructions manually building a tile server and ran in some problems.

When entering http://localhost:8080/osm_tiles/0/0/0.png

renderd shows this:

renderd[263]: DEBUG: Got incoming connection, fd 22, number 9
renderd[263]: DEBUG: Got incoming request with protocol version 2
renderd[263]: DEBUG: Got command RenderPrio fd(22) xml(default), z(0), x(0), y(0), mime(image/png), options()
renderd[263]: DEBUG: Failed to read cmd on fd 22
renderd[263]: DEBUG: Connection 8, fd 22 closed, now 8 left

It seems renderd is aware of the request, but there do never appear some files in /var/lib/mod_tile. The error.log of the apache webserver shows:

debug: init_storage_backend: initialising file storage backend at: /var/lib/mod_tile
[Mon Jun 01 12:33:15.828298 2015] [tile:info] [pid 104:tid 140230287886080] [client 172.17.42.1:60074] tile_storage_hook: handler(tile_serve), uri(/osm_tiles/0/0/0.png)
[Mon Jun 01 12:33:15.828355 2015] [tile:info] [pid 104:tid 140230287886080] [client 172.17.42.1:60074] Requesting style(default) z(0) x(0) y(0) from renderer with priority 5`

and then responds me with a 404 Page not found.

Answer 1

This issue happened due to an error in my configuration of renderd in /usr/local/etc/renderd.conf. Parts of the configuration file looked like th following snippet:

[renderd]
socketname=/var/run/renderd/renderd.sock
num_threads=4
tile_dir=/var/lib/mod_tile
stats_file=/var/run/renderd/renderd.stats

;[renderd01]
;iphostname=::1
;ipport=7654
;num_threads=4
;tile_dir=rados://tiles/etc/ceph/ceph.conf
;stats_file=/var/run/renderd/renderd.stats

;[renderd02]
;iphostname=::1
;ipport=7654
;num_threads=8
;tile_dir=memcached://
;stats_file=/var/run/renderd/renderd.stats

Those lines beginning with ; are commented out lines. Which is not allowed for lines containing [something] in those braces. So the solutions was to delete all lines beginning with ;. After that, my renderd did it's job perfectly.

Answer 2

In my case it was the num_threads=4 while trying to execute render_list -n 10 -z 0 -Z 18 -a

After changing num_threads=10 the error disappeared.

The wired thing is day before it was num_threads=4 and it did run with render_list -n 6 -z 0 -Z 18 -a and render_list -n 7 -z 0 -Z 18 -a and i didnt understand why htop was showing only 4 cores working.

I left it to run at night, when i came in the morning to check the progress it looks like nothing happening all cores was on 0 and syslog dident show any activity.

Today i added cores to the vm tried to run render_list -n 10 -z 0 -Z 18 -a and the error started. I changed to num_threads=10 and the error stopped