Testing Rails at Scale

Transcript

1. 1.

   Testing Rails at Scale BY @E MILS TO LARSK Y

2. 2.

   2

3. 3.

   3 Shopify 243,000+ S H O P S $14B+ TOTA

   L G M V 300M+ U N I Q U E V I S I T S / M O N T H 1000+ E M P LOY E E S
4. 4.

   4 CI Systems

5. 5.

   5 Scheduler Compute

6. 6.

   6 Scheduler Compute

7. 7.

   7 Scheduler Compute

8. 8.

   8 Managed Provider

9. 9.

   9 Managed Provider • Multi-tenant • Closed system • Examples

   – CircleCI, Codeship, Hosted TravisCI
10. 10.

    10 Unmanaged Provider

11. 11.

    11 Unmanaged Provider • Self-hosted • Open system • Examples

    – Jenkins, TravisCI, Strider
12. 12.

    12 Daily CI Stats 50,000+ C O N TA I

    N E R S B O OT E D F O R T E S T I N G 700 B U I L D S 42,000+ T E S T S P E R B U I L D 5 min B U I L D T I M E
13. 13.

    13 Shopify using a Hosted Provider • 20+ minute build

    times • Flakiness from resource starvation • Expensive
14. 14.

    14 A N EW HOPE

15. 15.

    15 Beginning of a Journey • Bring build times under

    5 minutes • Restore confidence in our CI • Maintain current budget
16. 16.

    16

17. 17.

    17 c4.8xlarge Webhooks Code push Agent Instructions

18. 18.

    18 Compute Cluster 5.4 TB M E M O R

    Y 3240 C P U C O R E S 90 F L E E T S I Z E AT P E A K c4.8xlarge I N S TA N C E T Y P E
19. 19.

    19 Instances • AWS Hosted • Managed with Chef •

    Memory bound • IO Optimizations
20. 20.

    20 SCROOGE

21. 21.

    21 Auto Scaling with Scrooge c4.8xlarge Capacity Requirements Scrooge Boot/Shutdown

    Nodes c4.8xlarge
22. 22.

    • AWS specific optimizations • Improve utilization • Not one

    size fits all 22 Optimizing Cost
23. 23.

    23 Graphing Productivity Active Buildkite Agents

24. 24.

    24 Graphing Productivity Active Buildkite Agents ? ? ?

25. 25.

    25 Graphing Productivity Active Buildkite Agents ? ? Lunch rush

    #1
26. 26.

    26 Graphing Productivity Active Buildkite Agents ? Commit + Push

    Lunch rush #1
27. 27.

    27 Graphing Productivity Active Buildkite Agents Lunch rush #2 Commit

    + Push Lunch rush #1
28. 28.

    28 Docker • Boot speedup • Test isolation • Distribution

29. 29.

    29 Building Containers with Locutus • Implements custom docker build

    API • Single EC2 machine • Forced debt repayment
30. 30.

    30 Test Distribution • Tests allocated based on container index

    • Ruby tests and browser tests are run on seperate containers • Outliers inflated build times
31. 31.

    31 Artifacts • Artifacts are uploaded to S3 by Buildkite

    Agents • Events log into Kafka & StatsD • Data tools are used to identify flaky tests
32. 32.

    32 Capacity Requirements Scrooge Boot/Shutdown Nodes Agent Instructions Webhooks Pull

    Containers Pull Revision
33. 33.

    D OC K ER S T R IK ES BAC

    K
34. 34.

    34 Rebel base is under Attack • Shipping second provider

    brought confusion • Locutus capacity issues • Tests times were still high
35. 35.

    35 Battling Confusion • Botched rollout • Instability further eroded

    developer confidence
36. 36.

    36 Clustering Locutus • Make it linearly scalable • Keep

    it stateless(-ish)
37. 37.

    37 Locutus Diagram Worker Worker Worker Worker Worker Pool Cache

    Ring Coordinator Docker Registry Container push New containers
38. 38.

    38 Test Distribution v2 • Loads all tests into Redis

    • Containers pull work off queue • No more container specialization
39. 39.

    39 Capacity Requirements Scrooge Boot/Shutdown Nodes Agent Instructions Webhooks Pull

    Containers Code push webhook
40. 40.

    40 RETU RN OF TH E STA BLE B UI

    LD
41. 41.

    41 Docker • No one tests starting 10,000’s of containers/day

    • Instability further eroded developer confidence • Every new version of docker had major bugs
42. 42.

    42 Handling Infrastructure Failures • At non-trivial scale, you’re guaranteed

    failures • Swallow infrastructure failures, never test failures • We still see 100+ container failures a day
43. 43.

    43 Treating Servers as Pets 1. Wait for reports to

    stream in of build issues 2. Flag node as in maintenance 3. Manually take node out of rotation 4. ssh into the node and follow playbook steps to cleanup disk
44. 44.

    44 Treating Servers as Cattle 1. Auto detect the failures

    2. Node removes itself from rotation 3. Node runs script to cleanup disk
45. 45.

    45 I love the internet.

46. 46.

    46

47. 47.

    47

48. 48.

    48 Test Distribution v3 • Containers record the tests they

    ran • Allow flakey tests to be rerun • Ensure no tests are lost
49. 49.

    49 Capacity Requirements Scrooge Boot/Shutdown Nodes Agent Instructions Webhooks Pull

    Containers Code push webhook
50. 50.

    CONCU LSO N

51. 51.

    51 Don’t build your own CI • Build times <10

    minutes • Small application
52. 52.

    52 Build your own CI • Build times >15 minutes

    • Monolithic Application • Parallelization Limits
53. 53.

    53 Lessons Learned • Commit 100% • Beware of Rabbit

    holes • Pets vs. Cattle
54. 54.

    54 Blank Slide Thanks! Fo llow m e o n

    Tw it te r @Em ilSt ol arsky
55. 55.

    55 Credits • Image of shipping containers: https://goo.gl/bXCn1X, https://goo.gl/cDDnYy •

    Images of Google DCs: https://goo.gl/UHVRc • Image of bank vault: https://goo.gl/fFN5EJ • Locutus: http://goo.gl/UyoJxx • Warehouse: https://goo.gl/5DiiR1 • Egyptian Temple: https://goo.gl/GjbLcq • Star wars: http://goo.gl/474wYG • Sinking container ship: http://goo.gl/U7rdR8, http://goo.gl/wlzlrm • Cats: http://goo.gl/9p2JXo, https://goo.gl/Ylhl60 • Cattle: http://goo.gl/IBdXmx • Star Wars: http://goo.gl/LatPEj • Creative Commons License: https://goo.gl/sZ7V7x