{"componentChunkName":"component---src-templates-post-template-js","path":"/posts/kubernetes-overview","result":{"data":{"markdownRemark":{"id":"1675991a-101c-50a3-8d0e-c47a2ed7e9bd","html":"

What is Kubernetes (k8s) ?

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Photographer: Rafael Cosquiere (https://www.pexels.com/zh-tw/photo/2064123/)
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In short, Kubernetes is a tool for developers to manage a cluster of computers.

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If you see the shape of Kubernetes logo, it's a rudder!
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Think of you have lots of service to manage…

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Non-offical Twitter System Architecture
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Why should we use Kubernetes ?

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Who invents Kubernetes ?

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Before we dive into details

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Core concepts of Kubernetes

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Fundaments

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Architecture

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A cluster can contain many nodes, a node can contain many pods, and a pod can contain many containers

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Important resource types

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Pod

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every pod has a unique IP iddress inside cluster (Cluster IP)
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When we use multiple containers in a pod ?

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When we should NOT use multiple containers in a pod ?

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when we want to scale up different applications inside a pod in different scale, we should separate it as different pods

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Service

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Pod-to-Pod communication

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Pod to connect external service

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External client to connect internal pod

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NodePort
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LoadBalancer
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Ingress
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ReplicaSet

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ReplicaSet
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Deployment

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Delete all old pods, and then create all new pods
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Create all new pods, and then delete all old pods
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Delete one, and create one, and so on
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Create several and delete several, and so on (rolling update)
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And actually, Deployment works by ReplicaSet:

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Persistent Volume

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Pods can be deleted/removed at any time, and all the files inside pod will disappear by default. However, for some of service, persistent storage is crucial. (e.g. DB service)

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We need a persistent storage even pod was deleted and re-created
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Inside kubernetes, the concept was splitted into PersistentVolume and PersistentVolumeClaim
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The work flow of using persistent storage in kubernetes
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Important resource types recap

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Tips for inspecting issues in Kubernetes cluster while on duty

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How to monitor whether application is running properly ?

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Reference

\n","fields":{"slug":"/posts/kubernetes-overview","tagSlugs":["/tag/kubernetes/","/tag/dev-ops/","/tag/deployment/","/tag/micro-services/"]},"frontmatter":{"date":"2021-03-30T19:12:04.772Z","description":"Kubernetes is one of the most important tools for managing the deployments of thousands of services in modern DevOps. With kubernetes, we can easily manage our application, and we can more effectively manage our computing resources (CPU, memory, storage). In this article, we will introduce the fundamental concepts pod, service, deployment and ingress.","tags":["Kubernetes","DevOps","Deployment","Micro services"],"title":"Basic Tutorial of Kubernetes","socialImage":{"publicURL":"/static/452a9717448efb8e150220b9c86ed451/social.jpeg"}}}},"pageContext":{"slug":"/posts/kubernetes-overview"}},"staticQueryHashes":["251939775","401334301","825871152"]}