Linux Conf Australia 2016 - The Twelve-Factor Container

In 2012 Adam Wiggins wrote [the twelve-factor app](http://12factor.net/), an essay widely considered canon for building cloud-native applications. The advent of the container ecosystem transformed these principles into hard constraints. This talk will review what you can _and cannot_ do with containers if you want to maintain repeatability, reliability, and portability.

Transcript

1. The Twelve-Factor Container • Twitter @caseywest • Email casey@geeknest.com • Web http://caseywest.com • Days since I last used that joke zero 1 @caseywest
2. Thanks a lot, Pivotal 2 @caseywest
3. This isn't really a talk about containers 3 @caseywest
4. This is a talk about operational maturity 4 @caseywest
5. You must be this tall to ride this ride 5 @caseywest
6. Audience Participation • Containers? • Schedulers? • Cloud? 6 @caseywest
7. Docker Docker Docker Docker Docker Docker Docker Docker 7 @caseywest
8. The factors 8 @caseywest
9. 1: One codebase tracked in revision control, many deploys 9 @caseywest
10. Anti-pattern Building separate images for staging and production 10 @caseywest
11. Anti-pattern Tags for dev and prod 11 @caseywest
12. Best Practice Use the environment and/or feature flags 12 @caseywest
13. 2: Explicitly declare and isolate dependencies 13 @caseywest
14. 2: Explicitly declare and isolate dependencies 14 @caseywest
15. Anti-pattern latest 15 @caseywest
16. Best Practice Declare version numbers of upstream dependencies 16 @caseywest
17. Best Practice Depend on base images for default filesystem and runtimes 17 @caseywest
18. 3: Store config in the environment 18 @caseywest
19. Anti-pattern config.yml 19 @caseywest
20. Anti-pattern properties.xml 20 @caseywest
21. Anti-pattern Hard-coded feature flags 21 @caseywest
22. Best Practice This one is literally about environment variables 22 @caseywest
23. Best Practice This one is literally about environment variables ! ‑ 23 @caseywest
24. 4: Treat backing services as attached resources 24 @caseywest
25. Anti-pattern No local disk 25 @caseywest
26. Anti-pattern No local disk 26 @caseywest
27. Anti-pattern No local disk 27 @caseywest
28. Best Practice Connect to network- attached services using connection info from the environment 28 @caseywest
29. 5: Strictly separate build and run stages 29 @caseywest
30. Anti-pattern Install on deploy 30 @caseywest
31. Best Practice Build immutable images then run those images 31 @caseywest
32. Painfully Obvious Best Practices Eat when hungry Sleep when tired Book Casey West for speaking gigs 32 @caseywest
33. Best Practice Respect the lifecycle: buid, run, destroy 33 @caseywest
34. 6: Execute the app as one or more stateless processes 34 @caseywest
35. Best Practice Schedule LRPs by distributing them across a cluster of physical hardware 35 @caseywest
36. Anti-pattern NFS 36 @caseywest
37. Anti-pattern NFS Need I say more? 37 @caseywest
38. 7: Export services via port binding 38 @caseywest
39. Best Practice port = Env.fetch(:port) 39 @caseywest
40. Best Practice my $port = $ENV{PORT}; 40 @caseywest
41. Best Practice private String getPort() { Map<String, String> env = System.getenv(); return env.get("PORT"); } 41 @caseywest
42. Best Practice let port = env::var("PORT").unwrap() 42 @caseywest
43. 8: Scale out via the process model 43 @caseywest
44. Best Practice Horizontally scale by adding instances 44 @caseywest
45. 9: Maximize robustness with fast startup and graceful shutdown 45 @caseywest
46. 10: Keep development, staging, and production as similar as possible 46 @caseywest
47. Best Practice Run containers in development 47 @caseywest
48. 11: Treat logs as event streams 48 @caseywest
49. Anti-pattern Random log files #yolo'd all over the file system 49 @caseywest
50. Anti-pattern Random log files #yolo'd all over the file system, bro 50 @caseywest
51. Best Practice STDOUT STDOUT STDOUT STDOUT 51 @caseywest
52. 12: Run admin/ management tasks as one-off processes 52 @caseywest
53. Anti-pattern Custom containers for tasks 53 @caseywest
54. Best Practice Reuse application images with specific entrypoints for tasks 54 @caseywest
55. You are now cloud-native 55 @caseywest
56. Repeatability Reliability Resiliency 56 @caseywest
57. Thank you Questions? 57 @caseywest
58. @caseywest Let's be friends 58 @caseywest