Some tips and tricks about deploying software in the FOSS4G ecosystem. Backend and frontend scaling solutions are offered, and tips for a scalable solution are offered.

1. Scalable OSGeo Stacks
From Tutorials to Production
David Zwarg
dzwarg@courbanize.com

2. Tutorials
• A good place to start!
• A bad place to end!

3. Production Environments
• Your production environment is a beautiful snowflake.
!
• Mileage may vary

4. Definition of Terms
• “Production”
• A data-driven, dynamic, scalable, web application
• “Tutorial”
• Anything else

5. “data-driven”
Anything that can be
changed in the
application is changed in
a database.
photo by Daniel Mitchell (flickr)

6. “dynamic”
Each visitor may have a
personalized “view” of
any URL.
photo by Jessa Dow-Anderson (flickr)

7. “scalable”
The application may be
run on 1 server or 100
servers.
photo by Tiny Delights (flickr)

8. “web
application”
An application that
provides rich interactivity
in a user’s web browser.

9. Good Tutorials Warn You
• Bad tutorials don’t

10. Tutorial #1: django
• https://docs.djangoproject.com/en/1.7/intro/tutorial01/
• Do not ignore these helpful notes:

11. Tutorial #2: geodjango
• “Use the source”
• Source installs can be just as dependable as package
management solutions

12. Side Note: Source Install
• Ensure that all script installations are scriptable
• Script & version package management installations
• Aim for a repeatable installation

13. Tutorial #3: celery
• More helpful log messages:
“UserWarning: Using settings.DEBUG
leads to a memory leak, never use this
setting in production environments!”

14. Side Note: Workers
• Long-running processes should be performed “out of
band”
• Use separate processes to do big tasks

15. Visitor Traffic
What your users feel
photo by Björn (flickr)

16. Visitor Traffic
What it really looks like
photo by joiseyshowaa (flickr)

17. Backend
Scaling
Tips for Servers
photo by Henrik Bennetsen (flickr)

18. Scaling GEOS & GDAL
• Single-threaded designs
• Apache: use the preform multiprocessing module
(mpm_prefork)
• gunicorn: use synchronous workers with many
worker_processes

19. Scaling Tiles
• Geoserver includes Geowebcache
• Cache WMS image tiles
• Automatic cache seeding
• Scriptable via REST

20. Scaling Tiles (cont.)
• Tilestache
• Plugs into Mapnik
• Use with MBTiles, Amazon S3, Memcache, etc

21. Scaling PostGIS
• Heroku provides the option of HA failover and PostGIS.
• Or, roll your own snowflake (WAL, Slony, Bucardo)

22. Frontend
Scaling
Tips for Web
Applications

23. OpenLayers
• Loading Strategies
• BBOX
• Vector “Resolution”
• Don’t drown in data

24. Use a CDN
• “Content Delivery Network”
• https://cdnjs.com
• https://ajax.googleapis.com
• http://cloudflare.net
• more!

25. General Tips
• Scale servers on demand
• Don’t overwhelm clients
• Focus on long-running processes & slow requests
• Use a cache

26. Scalable OSGeo Stacks
From Tutorials to Production
David Zwarg
dzwarg@courbanize.com