The overnight failure

This talk is based on a true horror story.

It is very likely that you too have "broken the internet" at some point in your career. Here I share the story of how I did it this time and the lessons I learned from this experience.

Presented at: wroc_love.rb 2017

1. The Overnight Failure
2. My name is Sebastián Tweet to me @sebasoga
4. Why?
5. We all have broken the internet
6. We normally don’t talk about it in public
7. Impostor syndrome
12. No matter the scale, our bugs affect our users lives
13. Big problems are usually the situations in which we learn the most
14. What’s the worst thing that could happen to you at work?
15. The Overnight Failure
16. How?
20. A B
21. A B
22. A B
23. A B
29. A B 0
30. A B A B 1
31. A B A B 1
32. A B 2
35. 9 A B
36. Once a week
40. Once a week
41. Once a week
42. Once a week
43. Once a week
45. Passenger Driver Total for trips
46. Once a week
47. Once a week
48. Once a week
49. Once a week
50. Recap • Users carpooled everyday • Billing process ran once a week • Passengers were charged • Driver were paid
51. What?
52. Once a week 6:00am
53. Saturday Wekly process was ran 06:00
54. Black Saturday
58. 6:25am
59. Black Saturday Wekly process was ran 06:00 06:25 User couldn’t pay for breakafast
60. @#$&! @#$&!
61. 6:25am @#$&! @#$&!! @#$&! @#$&! @#$&!!!
62. Black Saturday Wekly process was ran 06:00 06:25 User couldn’t pay for breakafast 06:34 Users reported bug
64. 6:34am
65. Manager: hey, sorry to call you this early but we have a problem with payments in production and a lot of customers are complaining about it
68. * photo provided by my former boss
69. Me: Sure, I’ll take a look right away. Let’s talk over chat
70. Me: (thinking I ended the call) Me: F********k!!!!!!
71. Me: (thinking I ended the call) Me: F********k!!!!!! Manager: I’m still in the call
72. Black Saturday Wekly process was ran 06:00 06:25 06:43 User couldn’t pay for breakafast 06:34 Users reported bug Manager woke me up
73. Lots of duplicated charges
74. Once a week
75. Once a week
76. Once a week
77. Once a week
78. Refunded charges
79. Once a week
80. Reversed transfers
81. Once a week 7:28am
82. Black Saturday Wekly process was ran 06:00 06:25 07:28 06:43 User couldn’t pay for breakafast 06:34 Users reported bug Manager woke me up Problem contained
85. Passenger: UserID: 9 Driver: User ID: 100 $10.00
86. Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 Passenger: UserID: 9 Driver: User ID: 100 $10.00 0 0 0
87. Once a week
88. Once a week
89. Once a week
90. Wrote tests, a fix and deployed it 10:50pm
91. Black Saturday Wekly process was ran 06:00 06:25 06:43 User couldn’t pay for breakafast 06:34 Users reported bug Manager woke me up 22:50 Deployed a fix to production Problem contained 07:28
92. Black Saturday Wekly process was ran 06:00 06:25 06:43 User couldn’t pay for breakafast 06:34 Users reported bug Manager woke me up 22:50 Deployed a fix to production 22:55 Started looking for a new job Problem contained 07:28
93. Black Saturday Wekly process was ran 06:00 06:25 06:43 User couldn’t pay for breakafast 06:34 Users reported bug Manager woke me up 22:50 Deployed a fix to production Problem contained 07:28
94. Thousands of users affected by the bug Users were charged up-to 200 times A single user was charged over $5k Maxed out credit cards. Emptied bank accounts
95. And people still say Ruby is slow
96. Refunds take up- to 5 business days
97. Reached out to users to offer an expedite reimbursement option
98. Why?
99. Embarrassing things happen
100. We need to make admiting mistakes easy
101. Trust that we won’t be judged
102. Make sure you understand what happened
103. Move slow
104. Document the problem
105. Document the fix
106. Document the lesson learnt
107. You are not your failures
108. It’s all temporary
109. #ibrokeshit
110. cookpad.com
111. sourcediving.com
112. We are hiring
113. Dzięki @sebasoga