监测pod的使用情况来做调整
概念：HPA可以获取每个pod的利用率、然后和HPA中定义的指标（如cpu、内存等使用情况）进行对比、同时计算出需要伸缩的具体值、最后实现pod数量的调整、其实HPA与之前的Deployment
控制器一样、也属于一种kubernetes资源对象、它通过追踪分析目标pod的负载变化情况、来确定是否需要针对性的调整目标pod的副本数量
1、安装部署metrics-server
metrics-server可以用来收集集群中的资源使用情况
1、安装git：yum install -y git
2、从github上克隆服务：·git clone -b v0.3.6 https://github.com/kubernetes-sigs/metrics-server.git #如果无法克隆就直接去git上下载·直接网页下载：https://github.com/kubernetes-sigs/metrics-server/tree/v0.3.6 #再上传解压·这里注意使用得版本：0.3.6是包含了deploy目录的 、0.4以上就没有这个目录了·且注意下载的0.3.6解压后会报错、直接解压再压缩里面的文件夹即可、再上传到服务器解压
3、修改deployment.yaml的参数、注意修改的是镜像和初始化参数：·进入解压后的文件里：cd metrics-server/deploy/1.8+/·编辑yaml文件：vim metrics-server-deployment.yaml
-------------------------------------------------------Ⅰ、#添加hostNetwork: truespec: #注意是在template下的spec添加 hostNetwork: trueserviceAccountName: metrics-serverⅡ、修改镜像仓库下载的地址：image:containers:- name: metrics-serverimage: registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.6 #修改为阿里云仓库Ⅲ、添加启动参数srgs：在containers下添加containers:- name: metrics-serverimage: registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.6imagePullPolicy: Alwaysargs:- --kubelet-insecure-tls- --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP
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4、安装部署metrics-server、去到该目录下metrics-server/deploy/1.8+/执行所有的yaml文件：·执行yaml文件：[root@master-1 1.8+]# kubectl apply -f ./ #这就安装了metrics-server了、运行在pod下的服务·查看生产的pod情况、默认在kube-system空间下生成：kubectl get pods -nkube-system---------------------------------------------------------------------------------- NAME READY STATUS RESTARTS AGEcoredns-6955765f44-7rtrd 1/1 Running 15 25dcoredns-6955765f44-gvx48 1/1 Running 15 25detcd-master-1 1/1 Running 17 25dkube-apiserver-master-1 1/1 Running 18 25dkube-controller-manager-master-1 1/1 Running 25 25dkube-flannel-ds-amd64-7b4gl 1/1 Running 1 17hkube-flannel-ds-amd64-ws2xl 1/1 Running 20 25dkube-proxy-777s9 1/1 Running 17 25dkube-proxy-xgfdl 1/1 Running 13 25dkube-scheduler-master-1 1/1 Running 25 25dmetrics-server-6b976979db-m7488 1/1 Running 0 2m3s #这个就是生成的pod 、上面其它都是系统自带的---------------------------------------------------------------------------------------------------------------------------5、查看node运行占用资源情况：kubectl top node
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NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
master-1 159m 3% 1000Mi 58%
node-1 44m 1% 337Mi 19%
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5、查看pod的资源占用情况：kubectl top pods -nkube-system图为vim metrics-server-deployment.yaml 文件修改情况
2、准备deployment和service
1、创建deployment： ·kubectl run nginx --image=nginx:1.17.1 --requests=cpu=100m -ndev·--requests=cpu=100m #cpu的限制、一定要加·查看deployment和生成的pod： kubectl get deploy,pod -ndev----------------------------------------------------------------------NAME READY UP-TO-DATE AVAILABLE AGEdeployment.apps/nginx 1/1 1 1 5m34s #这里的nginx是deployment的名字NAME READY STATUS RESTARTS AGEpod/nginx-778cb5fb7b-f4wbg 1/1 Running 0 5m34s #nginx-778cb5fb7b-f4wbg是pod的名字---------------------------------------------------------------------------------------------------------
2、创建server暴露给外界访问：·kubectl expose deployment nginx --type=NodePort --port=80 -ndev #--type=NodePort 生成一个给外界访问的端口·查看server：kubectl get deploy,pod,service -ndev--------------------------------------------------------------------NAME READY UP-TO-DATE AVAILABLE AGEdeployment.apps/nginx 1/1 1 1 10mNAME READY STATUS RESTARTS AGEpod/nginx-778cb5fb7b-f4wbg 1/1 Running 0 10mNAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGEservice/nginx NodePort 10.105.35.10 <none> 80:30114/TCP 89s #这里的30114端口是给外界访问的：ip:30114-------------------------------------------------------------------------------------------------------------------------------
3、部署HPA
1、创建HPA的yaml文件：
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apiVersion: autoscaling/v1 #注意这里的版本
kind: HorizontalPodAutoscaler
metadata:name: pc-hpanamespace: devspec:minReplicas: 1 #最小pod数量maxReplicas: 10 #最大pod数量targetCPUUtilizationPercentage: 3 #cpu使用率指标scaleTargetRef: #指定要控制nginx的信息apiVersion: apps/v1 kind: Deploymentname: nginx----------------------------------------------------------------------
2、执行文件创建HPA：kubectl create -f pc-hpa.yaml
3、查看HPA：kubectl get hpa -ndev
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NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
pc-hpa Deployment/nginx 0%/3% 1 10 1 45s#TARGETS 0%/3% 0是正在使用的cpu率、3是指定的阈值
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4、再开三个窗口实时观看deployment、pod和hpa的情况：·第一个窗口：kubectl get deploy -ndev -w·第二个窗口： kubectl get pods -ndev -w·第三个窗口： kubectl get hpa -ndev -w
5、使用postman工具向nginx服务发送访问请求：·http://192.168.177.160:30114/ #测试正常·向网址发送10000个请求观察hpa的cpu变化和pod、deployment的变化
