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Kubernetes 架构原则和对象设计

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Kubernetes 架构原则和对象设计

Shell

## 展示pod所有labels
k get pod --show-labels
## 为多个pod做负载均衡和服务发现（高可用，冗余部署，服务负载均衡）
kubectl expose deploy nginx --selector app=nginx --port=80 --type=NodePort
## 增加标签
k label ns default a=b
## 根据标签，找到pod
k get pod -l app=nginx

## -v 9开始日志debug模式
k get ns default -v 9
k get pods - v 9
## 增加annotations
k annotate ns default b=a
## 读取当前文件夹下的xx.yaml文件，并且指定ns
k create -f xx.yaml --namespaces xx

## 查看linux的环境变量
env

## 设置deploy级别的资源限制
kubectl set resources deployment nginx-deployment -c=nginx --limits=cpu=500m,memory=128Mi

## 查看ep
k get ep -A

## 查看crd
k get crd
## 查看crd的内容
k xxx -oyaml

Todo

  1. 优雅停止
  2. 联机删除
  3. rs更改，deploy不更改

Google Brog

Google Brog简介image-20220115100037865

Brog基本概念

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Borg架构

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应用高可用

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Brog调度原理

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Brog隔离型

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Kubernetes架构基础

什么是kubernetes（K8s）

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命令式（Imperative） vs 声明式（Declarative）

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Kubernetes：声明式系统

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Kubernetes采用于Brog类似的架构

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kubernetes的主节点（master node）

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kubernetes的工作节点（worker node）

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etcd

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ApiServer

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Controller Manager

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Controller Manager的工作流程

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Informer的内部机制

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控制器的协同工作原理

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常用命令

## 展示pod所有labels
k get pod --show-labels
## 为多个pod做负载均衡和服务发现（高可用，冗余部署，服务负载均衡）
kubectl expose deploy nginx --selector app=nginx --port=80 --type=NodePort
## 增加标签
k label ns default a=b

k edit deploy nginx，deploy的描述

apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "1"
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"name":"nginx-deployment","namespace":"default"},"spec":{"replicas":1,"selector":{"matchLabels":{"app":"nginx"}},"template":{"metadata":{"labels":{"app":"nginx"}},"spec":{"containers":[{"image":"nginx","name":"nginx"}]}}}}
  creationTimestamp: "2022-02-01T09:10:39Z"
  generation: 2
  name: nginx-deployment
  namespace: default
  resourceVersion: "10265191"
  uid: 0a724bbe-1b92-4f2e-96a6-48101db12849
spec:
  progressDeadlineSeconds: 600
  replicas: 3
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: nginx
  strategy:
  ## 滚动更新，可以填写绝对值和百分比
    rollingUpdate:
    ## 能够出来的最多新版本比例
      maxSurge: 25%
    ## 新版本出来之后，达到了这个比例不可用，则不在继续更新新版本了  
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx 
        imagePullPolicy: Always
        name: nginx
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30
status:
  availableReplicas: 3
  conditions:
  - lastTransitionTime: "2022-02-01T09:10:39Z"
    lastUpdateTime: "2022-02-01T09:10:56Z"
    message: ReplicaSet "nginx-deployment-85b98978db" has successfully progressed.
    reason: NewReplicaSetAvailable
    status: "True"
    type: Progressing
  - lastTransitionTime: "2022-02-01T09:34:49Z"
    lastUpdateTime: "2022-02-01T09:34:49Z"
    message: Deployment has minimum availability.
    reason: MinimumReplicasAvailable
    status: "True"
    type: Available
  observedGeneration: 2
  readyReplicas: 3
  replicas: 3
  updatedReplicas: 3
## 描述滚动更新的过程：nginx-deployment-7c658794b9新的rs
Normal  ScalingReplicaSet  28s   deployment-controller  Scaled up replica set nginx-deployment-7c658794b9 to 1
 Normal  ScalingReplicaSet  24s   deployment-controller  Scaled down replica set nginx-deployment-85b98978db to 2
 Normal  ScalingReplicaSet  24s   deployment-controller  Scaled up replica set nginx-deployment-7c658794b9 to 2
 Normal  ScalingReplicaSet  20s   deployment-controller  Scaled down replica set nginx-deployment-85b98978db to 1
 Normal  ScalingReplicaSet  20s   deployment-controller  Scaled up replica set nginx-deployment-7c658794b9 to 3
 Normal  ScalingReplicaSet  16s   deployment-controller  Scaled down replica set nginx-deployment-85b98978db to 0

Scheduler（调度器）

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Kubelet

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Kube-Proxy

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Kubectl

Kubectl 命令和 kubeconfig

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// -v 9开始日志debug模式
k get ns default -v 9
k get pods - v 9

kubectl常用命令

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kubectl describe

kubectl describe 展示资源的详细信息和相关 Event。

kubectl exec

kubectl exec 提供进入运行容器的通道，可以进入容器进行 debug 操作。

kubectl logs

Kubectl logs 可查看 pod 的标准输入(stdout, stderr)，与 tail 用法类似。

深入理解Kubernetes

Kubernetes生态系统

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Kubernetes设计理念

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Kubernetes Master

image-20220201191417932

Kubernetes分层架构

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image-20220201191935197

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API设计原则

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image-20220201192643068

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Kubernetes 如何通过对象的组合完成业务描述

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## 查看kubelet配置文件的路径：/var/lib/kubelet/config.yaml
## 查看k8s核心pod的yaml文件路径：/etc/kubernetes/manifests
ps -fe | grep kubelet

/usr/bin/kubelet 
--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf 
--kubeconfig=/etc/kubernetes/kubelet.conf 
--config=/var/lib/kubelet/config.yaml 
--network-plugin=cni 
--pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.6

————————————

kube-apiserver 
--advertise-address=10.252.189.253 
--allow-privileged=true 
--authorization-mode=Node,RBAC 
--client-ca-file=/etc/kubernetes/pki/ca.crt 
--enable-admission-plugins=NodeRestriction 
--enable-bootstrap-token-auth=true 
--etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt 
--etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt 
--etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key 
--etcd-servers=https://127.0.0.1:2379 
--kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt 
--kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key 
--kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname 
--proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt 
--proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key 
--requestheader-allowed-names=front-proxy-client 
--requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt 
--requestheader-extra-headers-prefix=X-Remote-Extra- 
--requestheader-group-headers=X-Remote-Group 
--requestheader-username-headers=X-Remote-User 
--secure-port=6443 
--service-account-issuer=https://kubernetes.default.svc.cluster.local 
--service-account-key-file=/etc/kubernetes/pki/sa.pub 
--service-account-signing-key-file=/etc/kubernetes/pki/sa.key 
--service-cluster-ip-range=10.96.0.0/12 
--tls-cert-file=/etc/kubernetes/pki/apiserver.crt 
--tls-private-key-file=/etc/kubernetes/pki/apiserver.key

架构设计原则

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引导（Bootstarpping）原则

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核心技术概念和API对象

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TyeMeta

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Metadata

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Label

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Annotations

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Spec和Status

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常用 Kubernetes 对象及其分组

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核心对象概览

Node

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Namespace

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Pod

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如何通过 Pod 对象定义支撑应用运行

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存储卷

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Pod网络

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资源限制

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等同于在每个 Pod 中设置 resources limits

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健康检查

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ConfigMap

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Secret(密钥对象)

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用户(User Account)& 服务帐户(Service Account)

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Service

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Replica Set（副本集）

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Deployment（部署）

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StatefulSet（有状态服务集）

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Statefulset 与 Deployment 的差异

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Job（任务）

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DaemonSet（后台支撑服务集）

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存储 PV 和 PVC

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CustomResourceDefinition

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参考资料
文章链接