1. Building Fintech
with Microservices and Kubernetes
SEPTEMBER, 2018
Irakli Nadareishvili,
Sr. Director, SharedTech, Capital One.

2. Irakli Nadareishvili
Senior Director, SharedTech, Capital One
• API & Microservices Governance
• Capital One’s Developer Tooling
• Co-author of “Microservice Architecture”
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3. AGENDA
Microservices Way
DevOps and Infrastructure
Software Design with Microservices

4. Align Around the Goal
“Why does Capital One care
about Microservices?”
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5. 11
“Speed and Safety at Scale and in Harmony”
Need for coordination is why we constantly
compromise between speed and safety.
Microservices Way:
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6. Microservices close the alignment loop!
AgileProcess:
Operations:
Product:
DevOps & CI/CID
Lean Product Dev
Toyota Production System: Think In Small Batches
Architecture: Microservices
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7. Data: Batch-size Is a Strong Predictor of Performance
Source: Accelerate, by Nicole Forsgren, PhD, Jez Humble, and Gene Kim

8. Getting to High-Performance Teams:
1 Measure Autonomy, to Gauge Progress
2 Combine Small Batches with Clarity on Long-Term View
3 Facilitate Experimentation and Design-Thinking
And yes, our teams are small (5 devs max), but that’s not the point.
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9. 1. Measure Autonomy, to Gauge Progress
Because:
Knowing you’re on the right path is paramount.
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10. 1. Measure Autonomy, to Gauge Progress
Initial attempts: tracking disruption events (qualitative).
Eventual (quantitative): Forsgren et al.’s metrics:
1. Lead time
2. Deploy frequency
3. Time to restore service

11. 2. Clarity on Long-Term View
Because:
99.999% of tech teams have Agile Myopia
(not a scientific fact, but a strong belief based on years of observation)
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12. Unexpected, Simple Cure for Agile Myopia

13. 3. Experimentation and Design-Thinking
Because:
Product-Market Mismatch and Rework
are devastatingly expensive.
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14. 3. Experimentation and Design-Thinking
“You’ve gotta start with the customer experience and
work backwards to the technology. You can’t start with
the technology and figure-out where you’re gonna sell
it.”
– Steve Jobs at the 1997 WWDC
@source: https://youtu.be/FF-tKLISfPE?t=114

15. AGENDA
Microservices Way
DevOps and Infrastructure
Software Design with Microservices

16. At the beginning:
1. ECS-based container deployments +
custom code, Mesos, Nomad, Kube
2. Dozen+ of CI/CD implementations
3. Non-standard secrets management
4. Resiliency tests ran quarterly
5. Dozens of teams building their own infra
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17. Now and Going Forward:
1. Kubernetes packaged for Capital One
2. Federated Ops of Kubernetes Clusters
3. Unified CI/CD (using Spinnaker) and auditable release
management with inner-sourced pipeline patterns.
4. Enterprise Solutions: Hashicorp Vault, chaos
engineering, test execution, code analysis, container
analysis
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18. Local [Kubernetes] Workspaces:
github.com/skaffold-microservices/workspace
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19. Kubernetes is Architect’s Tool (not just ops)
1. PODs make sidecars an architectural
reality
2. Istio is the best thing since sliced bread
3. Being ubiquitous is a value by itself
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20. AGENDA
Microservices Way
DevOps and Infrastructure
Software Design with Microservices

21. APIs vs. Microservices?
We made sure to invest in clarifying where
“Microservicization” fit with the already
mature API-First culture.
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22. 11
Microservices are not just small APIs:
Alexa
VoiceSkill
Chatbot
Web+
Mobile
App
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23. Our Design Process
1. Find Bounded Contexts w/ Event Storming
2. Identify Actors
3. Identify JTBDs
4. Define Queries and Actions
5. Design OpenAPI Spec
6. Get feedback on the spec
7. Implement APIs (usually w/ microservices)
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24. Bounded Contexts via Event Storming
Photos by: Justin Bachorik @justinbach

25. Example: Actors for DigiCoins
1. DigiCoin customer – a user using digicoin apps to
purchase or exchange digital coins.
2. DigiCoin Wallet – the platform
3. DigiCoin app – mobile app
4. …
DigiCoins is a fake exchange and wallet for digital currency. This is an entirely imaginary example for demo purposes only
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26. API Design: JTBDs
When _____ , I want to _____ , so I can _____ .
Circumstance, motivation, goal
Based on Alan Klement’s JTBD Story template https://jtbd.info/replacing-the-user-story-with-the-job-story-af7cdee10c27
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27. Example: JTBDs for DigiCoins
1. When a customer wants to buy coins they want to
see current price of a coin so that they can estimate
their buying power.
2. When a customer initiates coin purchase, they need
to add or reuse a payment method, so that they can
provide funds for the purchase
3. When a customer finalizes a coin purchase,
DigiCoins needs to charge the payment method, so
that it can make money
DigiCoins is a fake exchange and wallet for digital currency. This is an entirely imaginary example for demo purposes only
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28. Example: Queries for DigiCoins
1. Lookup of a coin “price”
1. Input: digital coin id, traditional currency code.
2. Response: conversion rate
2. Lookup of existing payment methods
1. Input: user identifier, payment type (coin, credit, bank transfer etc.)
2. Response: uuid and details of the payment method, status of the
payment method
DigiCoins is a fake exchange and wallet for digital currency. This is an entirely imaginary example for demo purposes only
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29. Example: Action(s) for DigiCoins
1. Charge a payment method to fund coin purchase
1. Input: payment method identifier and details.
2. Response: success or failure code
DigiCoins is a fake exchange and wallet for digital currency. This is an entirely imaginary example for demo purposes only
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30. Example: OpenAPI Spec
DigiCoins is a fake exchange and wallet for digital currency. This is an entirely imaginary example for demo purposes only
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32. Our Design Process
1. Find Bounded Contexts w/ Event Storming
2. Identify Actors
3. Identify JTBDs
4. Define Queries and Actions
5. Design OpenAPI Spec
6. Get feedback on the spec
7. Implement APIs (usually w/ microservices)
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33. QUESTIONS?