Picture-story Kubernetes

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OK for infrastructure beginners! Picture-story Kubernetes Aoi

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Self Introduction Name: Aoi Work as software engineer at Cybozu twitter: @_a0i

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First What I am going to speak ● Abstracts and consideration about Kubernetes Not speak about ● Description about Docker and containers ● How to useKubernetes

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Episode 1：Here Comes Kubernetes！　　Why Kubernetes was created Episode 2：Kubernetes and the Days 　　Deployment ﬂow for Kubernetes Episode 3：And the Journy Continues 　　Mechanisms to keep running Kubernetes 目次

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Here Comes Kubernetes！

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There was a big Java application Once Upon a Time...

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There Were No Problems in the Beginning But... A failure in one place aﬀects the whole takes time to start takes time to release

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The Developers Thought...

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Let’s Use Containers to Make Our Applications Smaller!

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But That Doesn't Make the Challenge Go Away. Hard to detect a failure and bring the container back up. Which server did I deploy the container? Where should I deploy the container?

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Hey It's me Kubernetes

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What Makes You Happy When You Use a Container? ・Containers are faster to boot than virtual machines. ・Applications are isolated in containers, which is convenient. On the other hand, containers become disorganized and diﬃcult to manage.

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App Guest OS Host OS Hardware Virtual Machine Container Hypervisor Guest OS Middle ware Middle ware App App App App App App App Middle ware Middle ware Hardware Host OS Container Runtime

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What is Kubernetes? Kubernetes is a portable, extensible, open-source platform for managing containerized workloads and services, that facilitates both declarative conﬁguration and automation. （From Kubernetes Document https://kubernetes.io/docs/concepts/overvie w/what-is-kubernetes/）

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1. Implement “Infrastructure As Code” through the use of resource configuration files called manifests 2. Standardized and abstracted by Kubernetes API, no need to know server-specific settings 3. Reconciliation Loop Kubernetes Makes Container Operations Convenient

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apiVersion: v1 kind: Pod metadata: name: nginx spec: containers: - name: test image: nginx:1.14.2 resources: requests: memory: "100Mi" Example of manifest：nginx container Which server to deploy？ What Operating System to use？Speciﬁcation of the server memory？ No need to worry!

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Reconciliation Loop Want two container OK！

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Reconciliation Loop Nooooooooo oh

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Reconciliation Loop ♪ Here’s two!

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Kubernetes And The Days

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Understand that Kubernetes helps operations but...

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・・・。 How exactly is it useful for developers?

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Application Development to Date Application Virtual Machine Abstracted for simplicity. Access by Browser! Conﬁg ﬁles

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To Develop Using Containers... Connection between containers? App App App Middle ware Middle ware Hardware Host OS Container Runtime How to Access from the outside? How to pass the conﬁguration ﬁle? How to use storage?

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Isn't it Getting Harder?

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Anyone Calling Me?

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This is What Happens When You Use Kubernetes! Service Container Container Pod ConﬁgMap

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Application Development Using Kubernetes CI Container Registry docker build docker push pull Service

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Application Development Using Kubernetes CI Container Registry docker build docker push pull Service manifest kubectl apply

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Is it Good to manually kubectl apply each time? kubectl apply kubectl apply How do you manage it? When to apply? Which environment to apply it to?

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CIOps push kick Manifest Repository CI Tool

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GitOps push pull Manifest Repository Deploy Tool

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Diﬀerence？ CIOps：Push-based model. It is easy to understand and intuitive because it automates what kubectl apply does. GitOps：Pull-based model. Because it is declarative, the managed manifest is always the correct conﬁguration.

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Kubernetes Architecture kube- apiserver etcd controller manager kubelet kube- proxy kubectl kube- scheduler Control Plane Node Node kubelet kube- proxy

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And the Journy Continues

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One night, the container seems to have gone bad... What do we do now?

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I'll Take Care!

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Various Health Check Mechanisms Remove non-healthy pods from services Create a new pod Service Service

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Move resources to another Node automatically. In Case of Node failure...

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Still, Failures Happen: Examples from Other Companies Deleting a cluster in the production environment （Spotify) Cleanup process removes Docker images from production environment (Airbnb)

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● No matter how good Kubernetes is, failures will occur. ● “Logging in to a VM, checking it with ps or systemctl, and looking at the log ﬁle" is no longer an option. Log! Metrics! Alert! Important! Observability

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Let's Enjoy Kubernetes!

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Reference Kubernetesとは何か？ https://kubernetes.io/ja/docs/concepts/overview/what-is-kubernetes/ Using Pods https://kubernetes.io/docs/concepts/workloads/pods/#using-pods 10 More Weird Ways to Blow Up Your Kubernetes - Jian Cheung & Joseph Kim, Airbnb https://www.youtube.com/watch?v=4CT0cI62YHk Keynote: How Spotify Accidentally Deleted All its Kube Clusters with No User Impact - David Xia https://www.youtube.com/watch?v=ix0Tw8uinWs Kubernetes Failure Stories https://k8s.af