Django Deployments Done Right

Deployment is the process of getting code from your laptop to a production-level server. What makes a "good" deployment? This talk will give you a tooling-agnostic look at the steps that you should be taking during deployment and show you how to overcome some common pitfalls in the process.

Transcript

1. Django Deployments Done Right Peter Baumgartner Founder, Lincoln Loop DjangoCon US 2015
2. About Me
3. Founder at Lincoln Loop
4. Co-author of High Performance Django
5. Django Deployments Done Right
6. Python Deployments Done Right
7. Deployments Done Right
8. What is a deployment?
9. What is a deployment? • Noun: The way your servers and software are setup
10. What is a deployment? • Noun: The way your servers and software are setup • Verb: The techniques used to install and update your software on 
 the servers
11. Why do you want a good deployment?
12. Uptime!
13. Humans
14. Bad Deployments
15. Bad Deployments • Stressful • Cause of burnout • Employee turnover
16. Good Deployments
17. Good Deployments • Non-events • Empowering
18. Business
19. Good Deployments • Ship faster • new features • bug fixes • failure recovery • Happy Humans • more productive • less turnover
20. What makes a good deployment?
21. It works
22. It is reliable
23. It is boring
24. It is user-friendly
25. It is fast
26. It is not disruptive
27. It is idempotent & deterministic
28. How to…
29. Use Configuration Management!
30. Configuration Management • Use Salt or Ansible 
 (unless other in-house experience) • Fabric is not a configuration management tool • Use it for everything
 (setup, updates, deploys, etc.)
31. Pin Dependencies
32. Pin Dependencies • Install exact versions PyPI, e.g. Django==1.8.4 • Consider setup.py and install_requires over requirements.txt • Can’t use PyPI? • Setup your own (pip2pi + Nginx or S3) • Vendor • Use a repo that you own
33. Reload, Don’t Restart
34. Reload, Don’t Restart • Don’t drop requests during a deploy • service {nginx,varnish} reload • Gracefully reload WSGI servers
 (gunicorn, uWSGI, etc.) • Works out-of-the-box with Upstart • systemd?
 ExecReload=/bin/kill -HUP $MAINPID
35. Make it User- Friendly
36. Make it User-Friendly ssh salt "sudo salt 'web*' state.highstate"
37. Make it User-Friendly ssh salt "sudo salt 'web*' state.highstate" ansible-playbook -i production web.yml
38. Make it User-Friendly ssh salt "sudo salt 'web*' state.highstate" ansible-playbook -i production web.yml
39. Make it User-Friendly ssh salt "sudo salt 'web*' state.highstate" ansible-playbook -i production web.yml fab production deploy
40. ssh salt "sudo salt 'web*' state.highstate" ansible-playbook -i production web.yml fab production deploy Make it User-Friendly
41. Make it User-Friendly fab production deploy fab staging deploy:my-branch fab staging logs fab production status
42. Make it User-Friendly
43. Make it User-Friendly
44. Isolate Each Build
45. Isolate Each Build • New build/release = New virtualenv • Broken builds don't take down the site • No cruft from previous builds • Fast painless rollbacks
46. Isolate Each Build
47. Isolate Each Build
48. Isolate Each Build • Multiple servers?
 Build once, deploy everywhere 1. Build wheels 2. Bundle 3. Ship • See platter.pocoo.org
49. Database Migrations
50. Database Migrations • Maintain backwards compatibility
 (for a few releases) • Big database and lots of traffic? • Avoid long table locks • See bit.ly/db-mg
51. Track Releases
52. Track Releases • Store commit hash and timestamp • Invaluable for regression tracking • NewRelic, Opbeat, Slack, etc.
53. Always Be Improving
54. Always Be Improving • Remember to think of the humans! • Can failures be avoided? • Can you make it faster? • Can you make it easier?
55. Thank You! Peter Baumgartner @ipmb pete@lincolnloop.com