Beyond Block Diagrams: Different Ways of Understanding K8s Architecture

Most introductory Kubernetes videos and blog posts use static block diagrams to illustrate the core components of Kubernetes and how they interact. These diagrams don’t convey the dynamic communication between the K8s control plane, nodes, and pods, and we owe it to ourselves and people new to the field more accurate and engaging ways of representing Kubernetes architecture. This talk will demonstrate a few different methods to visualize how Kubernetes components work together including a time-sequence diagram that models what happens when a user creates a pod using the Kubernetes command line tool, kubectl, and how to use Jaeger to see an http request move onto different nodes by traveling through a load balancer, to a service, and arriving at a specific pod. This talk is for people who are new to Kubernetes and want to understand how the system is designed, as well as experienced engineers who are curious about alternative ways of visualizing Kubernetes architecture.

Transcript

1. View Slide

2. Kim Schlesinger, DigitalOcean
   Beyond Block Diagrams: Different Ways of
   Understanding K8s Architecture
   

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3. Hi, I’m Kim
   Developer Advocate
   Site Reliability Engineer
   JavaScript Developer
   Elementary School Teacher
   2018
   @kimschles
   Beyond Block Diagrams
   

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4. Cloud Native Generation
   Photo source: https://unsplash.com/photos/8iZG31eXkks
   @kimschles
   Beyond Block Diagrams
   

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5. “Any framework that you
   can hold as a mental
   representation of an
   external reality.”
   - What is a mental model? by Julia Clavien
   Mental Models
   Photo source: https://unsplash.com/photos/3KGF9R_0oHs
   @kimschles
   Beyond Block Diagrams
   

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6. From the Kubernetes Documentation, Kubernetes Components: https://kubernetes.io/docs/concepts/overview/components/
   @kimschles
   Beyond Block Diagrams
   

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7. Hire, train and retain early-career engineers with limited
   computing experience
   Why?
   @kimschles
   Beyond Block Diagrams
   

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8. Takeaways
   1. Create diagrams that show the passage of time
   2. Use distributed tracing technology as a learning tool
   3. Build 3D models of Kubernetes clusters
   Photo source: https://unsplash.com/photos/_gEKtyIbRSM
   @kimschles
   Beyond Block Diagrams
   

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9. Agenda
   1. Time Sequence Diagram
   2. Distributed Traces + Diagram
   3. 3D Model
   @kimschles
   Beyond Block Diagrams
   

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10. Agenda
    1. Time Sequence Diagram
    2. Distributed Traces + Diagram
    3. 3D Model
    @kimschles
    Beyond Block Diagrams
    

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11. Example
    Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model @kimschles
    Beyond Block Diagrams
    

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12. kubectl create -f pod.yaml
    Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model @kimschles
    Beyond Block Diagrams
    

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13. Time Sequence Diagram
    @kimschles
    Beyond Block Diagrams
    

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14. Agenda
    1. Time Sequence Diagram
    2. Distributed Traces + Diagram
    3. 3D Model
    @kimschles
    Beyond Block Diagrams
    

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15. Agenda
    1. Time Sequence Diagram
    2. Distributed Traces + Diagram
    3. 3D Model
    @kimschles
    Beyond Block Diagrams
    

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16. Distributed Tracing
    “Distributed tracing, also called distributed request
    tracing, is a method used to profile and monitor
    applications, especially those built using a
    microservices architecture.”
    - OpenTracing Project
    Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model
    @kimschles
    Beyond Block Diagrams
    

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17. Meow-Micro 🐈
    ● 2 go microservices
    ● The meow-client accepts
    requests via a REST API and
    uses GRPC to communicate
    with the meow-server
    ● Fernando Diaz at GitLab
    Example
    Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model @kimschles
    Beyond Block Diagrams
    

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18. curl http://143.244.209.228/meow -X POST -d '{"name": "Meow-Mixer"}'
    Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model @kimschles
    Beyond Block Diagrams
    

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19. @kimschles
    Beyond Block Diagrams
    From Setting up Distributed Tracing with OpenTelemetry & Jaeger in Kubernetes Ingress-NGINX by Fernando Diaz
    Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model
    

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20. Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model @kimschles
    From Setting up Distributed Tracing with OpenTelemetry & Jaeger in Kubernetes Ingress-NGINX by Fernando Diaz
    Beyond Block Diagrams
    

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21. @kimschles
    Beyond Block Diagrams Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model
    

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22. @kimschles
    Beyond Block Diagrams
    Weaveworks kspan
    Example: rollout of a
    Deployment of two Pods
    From weaveworks-experiments/kspan: Turning Kubernetes Events into spans
    

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23. Agenda
    1. Time Sequence Diagram
    2. Distributed Traces + Diagram
    3. 3D Model
    @kimschles
    Beyond Block Diagrams
    

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24. Agenda
    1. Time Sequence Diagram
    2. Distributed Traces + Diagram
    3. 3D Model
    @kimschles
    Beyond Block Diagrams
    

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25. Example
    Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model @kimschles
    Beyond Block Diagrams
    

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26. kubectl create -f pod.yaml
    Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model @kimschles
    Beyond Block Diagrams
    

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27. Time Sequence Diagram | Distributed Tracing + Diagram | 3D Model @kimschles
    Beyond Block Diagrams
    

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28. Agenda
    1. Time Sequence Diagram
    2. Distributed Traces + Diagram
    3. 3D Model
    @kimschles
    Beyond Block Diagrams
    

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29. @kimschles
    Beyond Block Diagrams
    Recap
    

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30. “Any framework that you
    can hold as a mental
    representation of an
    external reality.”
    - What is a mental model? by Julia Clavien
    Mental Models
    Photo source: https://unsplash.com/photos/3KGF9R_0oHs
    @kimschles
    Beyond Block Diagrams
    

    View Slide

31. Cloud Native Generation
    Photo source: https://unsplash.com/photos/8iZG31eXkks
    @kimschles
    Beyond Block Diagrams
    

    View Slide

32. From the Kubernetes Documentation, Kubernetes Components: https://kubernetes.io/docs/concepts/overview/components/
    @kimschles
    Beyond Block Diagrams
    

    View Slide

33. Takeaways
    1. Create diagrams that show the passage of time
    2. Use distributed tracing technology as a learning tool
    3. Build 3D models of Kubernetes clusters
    Photo source: https://unsplash.com/photos/_gEKtyIbRSM
    @kimschles
    Beyond Block Diagrams
    

    View Slide

34. Hire, train and retain early-career engineers with limited
    computing experience
    Why?
    @kimschles
    Beyond Block Diagrams
    

    View Slide

35. Resources
    Examples of Kubernetes Time Sequence Diagrams
    ● Writing custom Kubernetes Scheduler - My Fake Tardis
    ● A Sequential Breakdown of the Kubernetes Deployment Process-
    ContainerLabs
    Time Sequence Diagram Generator
    ● SequenceDiagram.org - UML Sequence Diagram Online Tool
    @kimschles
    Beyond Block Diagrams
    

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36. Resources
    Distributed Tracing with Jaeger and ingress-nginx
    ● Jaeger: open source, end-to-end distributed tracing
    ● OpenTracing - NGINX Ingress Controller
    Tutorial
    ● Setting up Distributed Tracing in Kubernetes with OpenTracing, Jaeger,
    and Ingress-NGINX by Fernando Diaz, @awkwardferny
    Diagram Tool
    ● LucidChart
    @kimschles
    Beyond Block Diagrams
    

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37. Resources
    kspan
    ● Traces from Events: A New Way to Visualise Kubernetes Activities - Bryan
    Boreham
    ● weaveworks-experiments/kspan: Turning Kubernetes Events into spans
    @kimschles
    Beyond Block Diagrams
    

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38. @kimschles
    

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39. View Slide