Kubernetes Fundamentals

Kubernetes. It's so hot right now. But what is it?

This session is designed to show the fundamentals of Kubernetes. It assumes you know what a container is, that Kubernetes does something called "orchestration" with it, but that's it.

We'll cover the following: Container Registry, Pods, Services, Ingress, Scaling, Networking, mounting volumes, package management (Helm) and what's next.

Transcript

1. View Slide

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4. VM
   VM
   VM
   VM
   Server
   Host OS
   Hypervisor
   Guest OS Guest OS Guest OS
   App C
   App B
   App A
   Server
   Host OS
   Hypervisor
   

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5. VM
   VM
   VM
   VM
   Server
   Host OS
   Hypervisor
   Guest OS Guest OS Guest OS
   App C
   App B
   App A
   Server
   Host OS
   Hypervisor
   

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6. VM
   Container
   VM
   VM
   VM
   Server
   Host OS
   Hypervisor
   Guest OS Guest OS Guest OS
   App C
   App B
   App A
   Server
   Host OS
   Hypervisor
   Bins/Libs
   App A
   

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7. VM
   Container
   Container
   Container
   VM
   VM
   VM
   Server
   Host OS
   Hypervisor
   Guest OS Guest OS Guest OS
   App C
   App B
   App A
   Server
   Host OS
   Hypervisor
   Bins/Libs
   App B
   App C
   Bins/Libs
   App A
   Bins/Libs
   

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8. VM
   Container
   Container
   Container
   VM
   VM
   VM
   Server
   Host OS
   Hypervisor
   Guest OS Guest OS Guest OS
   App C
   App B
   App A
   Server
   Host OS
   Hypervisor
   Bins/Libs
   App B
   App C
   Bins/Libs
   App A
   Bins/Libs
   

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10. Image Name
    Process
    started in an
    executing
    container
    Initializes a
    new build
    stage and sets
    the base
    image
    Execute commands
    in a new layer on
    top of the current
    image and commit
    results
    Provide defaults
    for an executing
    container
    Captures the steps to build a container
    image
    Version-able asset in your DevOps flows
    Configuration-as-Code
    

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12. VM
    Container
    Container
    Container
    Server
    Host OS
    Hypervisor
    Bins/Libs
    App B
    App C
    Bins/Libs
    App A
    Bins/Libs
    Container Image
    Container Image
    Container Image
    Container Image
    Container Image
    Container Image
    

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13. VM
    Container
    Container
    Container
    Server
    Host OS
    Hypervisor
    Bins/Libs
    App B
    App C
    Bins/Libs
    App A
    Bins/Libs
    Container Image
    Container Image
    Container Image
    Container Image
    Container Image
    Container Image
    

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15. VM
    Container
    Container
    Container
    Server
    Host OS
    Hypervisor
    Bins/Libs
    App B
    App C
    Bins/Libs
    App A
    Bins/Libs
    VM
    Container
    Container
    Container
    Server
    Host OS
    Hypervisor
    Bins/Libs
    App B
    App C
    Bins/Libs
    App A
    Bins/Libs
    

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19. Container Orchestrator
    

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20. Container Orchestrator
    Cluster
    

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21. VM
    Server
    Host OS
    Hypervisor
    Guest OS
    Container Orchestrator
    Cluster
    

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22. VM
    Server
    Host OS
    Hypervisor
    Guest OS
    Cluster
    

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23. Kubernetes comes from the Greek
    word κυβερνήτης:, which
    means helmsman or ship pilot, ie: the
    captainer of a container ship.
    "Kubernetes is an open-source system for automating deployment,
    scaling, and management of containerized applications."
    

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24. VM
    Server
    Host OS
    Hypervisor
    Guest OS
    Kubernetes
    Master
    Cluster
    Node Node Node
    Node Node Node
    

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25. AKS reduces the complexity and operational
    overhead of managing Kubernetes by
    offloading much of that responsibility to
    Azure.
    You only pay for the worker nodes within
    your clusters, not for the master nodes
    

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27. Kubernetes
    Cluster
    Node Node Node
    Node Node Node
    

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28. Master
    Cluster
    Node
    api-server
    etcd
    controller-
    manager
    scheduler
    

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29. Master
    Cluster
    Node
    api-server
    etcd
    controller-
    manager
    scheduler
    

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30. Container
    Container
    Container
    Bins/Libs
    App B
    App C
    Bins/Libs
    App A
    Bins/Libs
    Where do the Containers go?
    

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31. Container
    Container
    Container
    Bins/Libs
    App B
    App C
    Bins/Libs
    App A
    Bins/Libs
    Introducing…. Pods!
    

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32. Pods
    Master
    Cluster
    Node
    api-server
    etcd
    controller-
    manager
    scheduler
    

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33. Pods
    Master
    Cluster
    Node
    api-server
    etcd
    controller-
    manager
    scheduler
    

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34. ratings-api
    Label(s) app=ratings-api
    Container-image my.azurecr.io/ratings-api
    Port 3001
    (VolumeMount) /mnt/share
    (Resources)
    ratings-web
    Label(s) app=ratings-web
    Container-image my.azurecr.io/ratings-web
    Port 3000
    (VolumeMount) /mnt/share
    (Resources)
    Pods – What are they?
    otherApp
    Label(s) app=otherApp
    Container-image other.azurecr.io/other
    App
    Port 4045
    (VolumeMount) /mnt/share
    Metadata that describes how the containers are configured.
    

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35. Deployments
    Metadata that describes how to deploy a pod
    More Metadata
    ratings-web
    replicas 2
    ratings-web
    Label(s) app=ratings-web
    Container-
    image
    my.azurecr.io/
    ratings-web
    Port 3000
    (Volume) …
    (Resources) …
    

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36. Cluster
    Node Node
    Master
    

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37. Cluster
    Node Node
    Master
    

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38. Cluster
    Node Node
    Master
    

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39. ratings-web2
    Label(s) app=ratings-web
    Container-
    image
    my.azurecr.io/
    ratings-web
    Port 3000
    Services
    Metadata that describes how to reach the pods
    Yet More Metadata!
    ratings-web
    Selector app=ratings-web
    Port Mapping 8080:3000
    Type (Internal
    or External)
    LoadBalancer
    ratings-web1
    Label(s) app=ratings-web
    Container-
    image
    my.azurecr.io/
    ratings-web
    Port 3000
    

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40. Services Cluster
    Node Node
    Service
    ratings-web
    IP Address
    Master
    

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41. Services Cluster
    Node Node
    Service
    ratings-web
    IP Address
    Master
    

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42. Manual via Kubernetes Portal
    Infra-as-Code a YAML file
    

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44. Scaling Pods
    ratings-web
    replicas 3
    ratings-web
    Label(s) app=ratings-web
    Container-
    image
    my.azurecr.io/
    ratings-web
    Port 3000
    (Volume) …
    (Resources) …
    

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45. Scaling Pods
    ratings-web
    replicas 6
    ratings-web
    Label(s) app=ratings-web
    Container-
    image
    my.azurecr.io/
    ratings-web
    Port 3000
    (Volume) …
    (Resources) …
    

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46. Node
    Master
    Cluster
    Node Node
    

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47. Node
    Node
    Node
    Master
    Cluster
    Node
    az scale –name –g –node-count
    

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48. Azure Container Instances
    Node
    With Azure Container Instances
    Master
    Cluster
    Node
    az enable-addons –g –name
    –addons –subnet-name
    

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50. Master
    Cluster
    Service
    ratings-web
    IP Address
    Updated App Updated App Updated App
    

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51. Node
    Node
    Node
    Master
    Cluster
    Service
    ratings-web
    IP Address
    

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52. Node
    Node
    Node
    Master
    Cluster
    Service
    ratings-web
    IP Address
    

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54. Why do we need volumes ?
    Volume
    (state)
    

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56. PV vs PVC
    Volumes
    emptyDir
    hostPath
    Persistent Volume
    Claim (PVC)
    ConfigMap
    Security
    ….
    Persistent Volume (PV)
    

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57. Dynamic Storage in AKS – Azure Disk
    

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59. Inter-Pod Communication
    

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60. Why Services?
    

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61. Why Services?
    

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63. How does ClusterIP Work
    

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64. How does LoadBalancer Work
    

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65. How does NodePort Work
    

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66. How does Ingress Controller Work
    

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68. 1. Kubernetes users communicate with
    API server and apply desired state
    2. Master nodes actively enforce
    desired state on worker nodes
    3. Worker nodes support
    communication between containers
    Kubernetes
    control
    API server
    replication, namespace,
    serviceaccounts, etc.
    -controller-
    manager -scheduler
    etcd
    Master node
    Worker node
    kubelet Service
    Docker
    Pods Pods
    Worker node
    kubelet Service
    Docker
    Pods Pods
    Internet
    4. Worker nodes support
    communication from the
    Internet
    

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69. API server
    Controller
    Manager
    Scheduler
    etcd
    Store
    Cloud
    Controller
    Self-managed master node(s)
    • Automated upgrades, patches
    • High reliability, availability
    • Easy, secure cluster scaling
    • Self-healing
    • API server monitoring
    • At no charge
    Customer VMs
    App/
    workload
    definition
    User
    Docker
    Pods
    Docker
    Pods
    Docker
    Pods
    Docker
    Pods
    Docker
    Pods
    Schedule pods over
    private tunnel
    Kubernetes API
    endpoint
    Azure managed control plane
    

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70. Task The old way With Azure
    Create a cluster Provision network and VMs
    Install dozens of system components including etcd
    Create and install certificates
    Register agent nodes with control plane
    az aks create
    Upgrade a cluster Upgrade your master nodes
    Cordon/drain and upgrade worker nodes individually
    az aks upgrade
    Scale a cluster Provision new VMs
    Install system components
    Register nodes with API server
    az aks scale
    

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73. Operationalizing Kubernetes
    

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74. Helm
    Helm Charts helps you define, install, and upgrade even
    the most complex Kubernetes application
    pods
    services
    Chart.yml
    db
    deployments
    ci
    …
    

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75. Helm
    The best way to find, share, and use software built
    for Kubernetes
    Manage complexity
    Charts can describe complex
    apps; provide repeatable app
    installs, and serve as a single
    point of authority
    Easy updates
    Take the pain out
    of updates with in-place
    upgrades and custom
    hooks
    Simple sharing
    Charts are easy to
    version, share, and host
    on public or private
    servers
    Rollbacks
    Use helm rollout to
    roll back to an older
    version of a release with
    ease
    

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76. Many Choices
    

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77. A fully managed service of Red Hat OpenShift on Azure, jointly, engineered, operated and
    supported by Microsoft and Red Hat
    

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78. https://kubernetes.io/docs/home/
    https://aka.ms/learnkubernetes
    https://aksworkshop.io/
    https://helm.sh/blog/helm-3-preview-pt7/
    https://docs.microsoft.com/en-us/azure/aks/best-practices
    

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