Kubernetes: Changing the Way we Think and Talk about Computing

We're looking at a major revolution in Cloud Computing, the likes of Docker, CoreOS, Mesos, Kubernetes and many other technologies are not only changing the way we harness our computing power but are also changing the way that we talk about it. In this session we'll look at the new metaphors of computing through the lens of Kubernetes. We'll make use of the Kubernetes API and visualization libraries to get to a better understanding of the underlying mechanics of Kubernetes, we'll build clusters, schedule pods, group containers and expose services, and we'll visually demonstrate how they are all wired together.

Presented at Container Camp London (Sep 2015)

Transcript

1. Changing the way we Think and Talk about Computing
   Kubernetes
   

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2. @tekgrrl #kubernetes #containercamp
   Mandy Waite
   Developer Advocate
   +MandyWaite
   @tekgrrl
   

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3. Image by Connie
   Zhou
   

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4. @tekgrrl #kubernetes #containercamp
   job hello_world = {
   runtime = { cell = 'ic' } // Cell (cluster) to run in
   binary = '.../hello_world_webserver' // Program to run
   args = { port = '%port%' } // Command line parameters
   requirements = { // Resource requirements
   ram = 100M
   disk = 100M
   cpu = 0.1
   }
   replicas = 5 // Number of tasks
   }
   10000
   Developer View
   

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5. @tekgrrl #kubernetes #containercamp
   Developer View
   

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6. @tekgrrl #kubernetes #containercamp
   web browsers
   BorgMaster
   link shard
   UI
   shard
   BorgMaster
   link shard
   UI
   shard
   BorgMaster
   link shard
   UI
   shard
   BorgMaster
   link shard
   UI
   shard
   Scheduler
   borgcfg web browsers
   scheduler
   Borglet Borglet Borglet Borglet
   Config
   file
   BorgMaster
   link shard
   UI
   shard
   persistent store
   (Paxos)
   Binary
   What just
   happened?
   Cell
   Storage
   Developer View
   

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7. Hello
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   Image by Connie
   Zhou
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   Hello
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8. #dockerjp #kubernetes @tekgrrl
   Developer View
   

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9. #dockerjp #kubernetes @tekgrrl
   task-eviction rates and
   causes
   Failures
   

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10. #dockerjp #kubernetes @tekgrrl
    Resource reclamation
    time
    limit: amount of resource
    requested
    usage: actual resource
    consumption
    Efficiency
    reservation: estimate of
    future usage
    potentially reusable
    resources
    

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11. #dockerjp #kubernetes @tekgrrl
    one
    machine
    Efficiency
    Advanced bin-
    packing
    algorithms
    Experimental
    placement of
    production VM
    workload, July 2014
    

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12. #dockerjp #kubernetes @tekgrrl
    Efficiency
    Used CPU
    Used CPU (in cores)
    Used Memory
    Used Memory
    Available
    Resources
    Stranded
    Resources
    

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13. #dockerjp #kubernetes @tekgrrl
    The Machine is just a Resource Boundary
    Machines (Virtual and Bare Metal) have
    shapes:
    2GB/Core, 4GB/Core, 8GB/Core, etc
    Workloads have shapes too:
    1GB/Core, 3.5GB/Core, etc Machine Shapes
    Workload Shapes
    

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14. #dockerjp #kubernetes @tekgrrl
    Computing Tetris
    

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15. #dockerjp #kubernetes @tekgrrl
    Resource Stranding
    5.5GB RAM
    Inaccessible
    CPU Fully
    Utilized
    

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16. #dockerjp #kubernetes @tekgrrl
    Bin Packing
    1 CPU
    Available
    5.5GB RAM
    Available
    

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17. #dockerjp #kubernetes @tekgrrl
    Bin Packing
    

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18. #dockerjp #kubernetes @tekgrrl Images by Connie
    Zhou
    Observations:
    ● Efficiency comes from
    ○ Scavenging unused allocations
    ○ Effective Prioritization
    ○ Sharing resources
    ○ Overcommit
    ○ Smarter Scheduling
    ● The Datacenter is one big System
    ○ The machine is just a resource
    boundary
    ● Containers make everyone more
    productive
    http://kubernetes.io
    http://goo.gl/1C4nuo (Borg paper)
    

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19. Kubernetes
    

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20. @tekgrrl #kubernetes #containercamp
    Greek for “Helmsman”; also the root of the
    word “Governor”
    • Orchestrator for Docker containers
    • Supports multi-cloud environments
    • Inspired and informed by Google’s
    experiences and internal systems
    • Open source, written in Go
    Manage applications, not machines
    Kubernetes
    

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21. @tekgrrl #kubernetes #containercamp
    web browsers
    y
    Kubelet Kubelet Kubelet Kubelet
    Kubernetes Master
    Replication
    Controller
    Scheduler
    API Server
    Kube-UI
    Container
    Registry
    kubectl
    Proxy
    
    web browsers
    Developer View (Kubernetes)
    

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22. @tekgrrl #kubernetes #containercamp
    Service
    Label selectors:
    version = 1.0
    type = Frontend
    Service
    Label selector:
    type = FE
    Replication
    Controller
    Pod
    Pod
    frontend
    Pod
    version= v1 version = v1
    Replication
    Controller
    version = v1
    #pods = 2
    show: version = v2
    type = FE type = FE
    VIP
    Canary Example
    Replication
    Controller
    Replication
    Controller
    version = v2
    #pods = 1
    show: version = v2
    Pod
    frontend
    Pod
    version = v2
    type = FE
    

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23. @tekgrrl #kubernetes #containercamp
    Developer View (Replication Controller)
    spec:
    containers:
    - name: php-guestbook
    image: php-guestbook:containercamp
    resources:
    limits:
    memory: "128Mi"
    cpu: "500m"
    ports:
    - containerPort: 80
    protocol: TCP
    replicas: 1
    10000
    

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24. @tekgrrl #kubernetes #containercamp
    php
    MySQL
    php
    php
    python
    memcached
    d
    Mapping to Kubernetes
    Client
    

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25. @tekgrrl #kubernetes #containercamp
    Node3
    Kubelet Proxy
    Pod
    Container
    Container
    Container
    Container
    Pod
    Container
    Container
    Container
    Container
    Node3
    Kubelet Proxy
    Pod
    Container
    Container
    Container
    Container
    Pod
    Container
    Container
    Container
    Container
    Node1
    Kubelet Proxy
    Pod
    Container
    Container
    Pod
    $ kubectl proxy --www=k8s-visualizer/
    Visualizing Kubernetes
    Master
    APIs
    Scheduling
    REST
    (pods, services,
    controllers)
    AuthN
    Scheduler
    Replication
    Controller
    Container
    

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26. Demo - Visualization
    

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27. @tekgrrl #kubernetes #containercamp
    A Quick Guide to Nodes
    Node2
    Kubelet Proxy
    disk = ssd
    type = FE
    Resources
    Labels
    Disks
    

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28. @tekgrrl #kubernetes #containercamp
    Scheduling Capabilities Step 1 - Filtering
    Node Resources
    I need 3.5GB
    RAM and 2 Cores
    Node Resources
    Node Resources
    Node Resources
    podFitsResources
    

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29. @tekgrrl #kubernetes #containercamp
    Scheduling Capabilities Step 1 - Filtering
    Node1
    Kubelet Proxy
    Node2
    Kubelet Proxy
    Node3
    Kubelet Proxy
    Demo-mysql-disk
    I need demo-
    mysql-disk
    NoDiskConflict
    

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30. @tekgrrl #kubernetes #containercamp
    PodFitsHost: Filter by NodeName
    PodSelectorMatches: Filter by Node
    Label (key and value)
    CheckNodeLabelPresence: Filter by
    Node Label
    Scheduling Capabilities Step 1 - Filtering
    

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31. @tekgrrl #kubernetes #containercamp
    LeastRequestedPriority Rank by how much free space will be
    left on the node after the node is deployed [Default]
    CalculateNodeLabelPriority Prefer nodes with the specified
    label
    BalancedResourceAllocation CPU and Memory is balanced after
    the Pod is deployed [Default]
    CalculateSpreadPriority minimise number of Pods from the
    same service on the same node
    CalculateAntiAffinityPriority minimise number of Pods from the
    same service on nodes with the same value for a particular label
    Scheduling Capabilities Step 2 - Ranking
    

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32. @tekgrrl #kubernetes #containercamp
    Kubernetes 1.0 as of mid July
    • Formerly announced at OSCON in July
    Open sourced in June, 2014
    • won the BlackDuck “rookie of the year” award
    Google launched Google Container Engine (GKE)
    • hosted Kubernetes
    • https://cloud.google.com/container-engine/
    Roadmap:
    • https://github.com/GoogleCloudPlatform/kubernetes/milestones
    Kubernetes Status
    

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33. @tekgrrl #kubernetes #containercamp
    Google Container Engine (GA)
    Managed Kubernetes (Kubernetes v1)
    Manages Kubernetes master uptime
    Manages Updates
    Cluster Resize via Managed Instance
    Groups
    Centralised Logging
    Google Cloud VPN support
    

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34. @tekgrrl #kubernetes #containercamp
    Kubernetes is Open Source
    We want your help!
    http://kubernetes.io
    https://github.com/GoogleCloudPlatform/kubernetes
    irc.freenode.net #google-containers
    @kubernetesio
    

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35. @tekgrrl #kubernetes #containercamp
    Tweet questions to:
    @tekgrrl
    Questions
    

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36. @tekgrrl #kubernetes #containercamp
    Example of Resource based scheduling
    Node1 (1 CPU)
    Kubelet Proxy
    Pod (0.6 CPU)
    Container
    Container
    Node2 (1 CPU)
    Kubelet Proxy
    Pod (0.6 CPU)
    Container
    Container
    Node3 (1 CPU)
    Kubelet Proxy
    Pod (0.6 CPU)
    Container
    Container
    

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