This document summarizes Capital One's transition to using microservices and Kubernetes. It discusses how Capital One aligned around using microservices to balance speed and safety at scale. It also describes Capital One's move to a unified CI/CD pipeline and operations of Kubernetes clusters. The document outlines Capital One's software design process for microservices, including identifying bounded contexts, actors, queries, and actions to design API specifications.

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?