1. Prodution Architecture and Deployment with Fabric - Andy McCurdy - @andymccurdy

2. Whiskey Media

3. Whiskey Sites

4. Your First Django App

6. mod_wsgi

7. use daemon mode

8. threads more efficient

9. processes if you're unsure of thread safetyWSGIDaemonProcess my-site python-path=/home/code/ processes=2 threads=150 maximum-requests=5000 WSGIProcessGroup my-site WSGIScriptAlias / /home/code/my-site/deploy/wsgi/my-site.wsgi

11. Use Nginx to proxy traffic to Apache

12. Meanwhile Nginx serves mediaupstream my-site { server 127.0.0.1:8000; } server { listen 80; location ~ ^/media/ { root /home/code/my-site; expires 30d; } location / { proxy_pass http://my-site; proxy_set_header X-Real-IP $remote_addr; } }

14. PostgreSQL

15. Frank Wiles @ www.revsys.com

16. MySQL

18. It's incredibly easy...# settings.py MIDDLEWARE_CLASSES = ( 'django.middleware.cache.UpdateCacheMiddleware', 'django.middleware.common.CommonMiddleware', 'django.middleware.cache.FetchFromCacheMiddleware') CACHE_BACKEND = 'memcached://127.0.0.1:11211/' CACHE_MIDDLEWARE_SECONDS = 60*5 # 5 minutes CACHE_MIDDLEWARE_ANONYMOUS_ONLY = True

20. Run DB migrations / syncdb

22. As much RAM as possible

23. Write-heavy (>10%)? Get fast disks

26. Multiple load balancers for redundancy

27. Message queues

28. Crons

29. Search daemons (Solr, Sphinx)

32. Maintenance splash page

33. Run DB migrations

34. Install/Upgrade Python dependencies

35. Add a new web server to the cluster

37. Deployment Options Fabric + Very simple, tasks are just Python functions + Easy to chain together tasks to create complex scripts out of bite size pieces - No source control integration - No out of box support - Some bugs, although fairly easy to work around, and new maintainer is working on fixes

39. need a fabfile.py

40. from fabric.api import *

41. be mindful of tasks that may fail

42. each remote command starts fresh

44. run() - Run a command remotely

45. sudo() - Run a command remotely as another user

46. put() - Copy a file from local to remote

47. get() - Copy a file from remote to local

49. Use SSH keys

50. Control access to root user via sudoers

52. Hosts and Roles

53. Code Repositories

54. Whatever you need

55. ~/fabricrc

56. Global settings or all Fabric deployments

58. Tasks # fabfile.py def uptime(): run('uptime') $> fab uptime -H 10.1.1.3 [10.1.1.3] run: uptime [10.1.1.3] out: 05:20:39 up 88 days, 12:00, 0 users, load average: 0.03, 0.03, 0.00

59. Mapping Roles to Tasks # fabfile.py @roles('web') def uptime(): run('uptime') $> fab uptime [10.1.1.1] run: uptime [10.1.1.1] out: 05:20:39 up 88 days... [10.1.1.2] run: uptime [10.1.1.2] out: 05:20:39 up 88 days...

61. Can't override decorated tasks at command line as docs suggestdef default_roles(*role_list): def selectively_attach(func): if not env.roles and not env.hosts: return roles(*role_list)(func) else: if env.hosts: func = hosts(*env.hosts)(func) if env.roles: func = roles(*env.roles)(func) return func return selectively_attach

62. All better now #fabfile.py @default_roles('web', 'db') def uptime(): run('uptime') $> fab uptime # runs on all hosts in the 'web' and 'db' roles $> fab uptime --roles lb # runs only on hosts in the 'lb' role

64. Use a context manager when failures are anticipated# fabfile.py from __future__ import with_statement # py2.5 def symlink_me(): with settings(warn_only=True): run('rm /path/to/symlink') run('ln -s /home/andy /path/to/symlink')

66. Great for sys-admin and one-off tasks# fabfile.py @default_roles('all') def invoke(command): "Invoke an arbritrary command" sudo(command) # install new packages on all hosts in one command $> fab invoke:"apt-get install git-core"

67. Real World Tasks $> fab --list Available commands: bounce_wsgi_procs Bounce the WSGI procs by touching the files deploy Full deployment deploy_media Push media to S3 invoke Invoke an arbritrary command migrate Run any migrations via South reload_nginx Update Nginx's running config splash_off Configure Nginx to serve the site splash_on Configure Nginx to serve a downed-site page update_repositories Push code to servers update_dependencies Update dependencies to third party libs

68. Whiskey's Deployment def deploy(splash='no'): "Full deployment" deploy_media() update_cached_repositories() update_dependencies() generate_releases() if splash == 'yes': splash_on() _symlink_code() migrate() bounce_wsgi_procs() if splash == 'yes': splash_off() $> fab deploy:splash=yes

69. Questions?