Kubernetes/k8s之HPA，命名空间资源限制-编程知识

Horizontal Pod Autoscaling:po的水平自动伸缩

这是k8s自带的模块

pod占用cpu比例达到一定的阀值，会触发伸缩机制。

根据cpu的阀值触发伸缩机制

replication controller 副本控制器控制pod的副本数

deployment controller 节点控制器部署pod

hpa控制副本的数量，以及如何控制部署pod

1、hpa基于kube-controll-manager服务，周期性的检测pod的cpu使用率，默认30秒检测一次

2、hpa和replication controller，deployment controller都属于k8s的资源对象。通过跟踪分析副本控制器和deployment的pod的负载变化，针对性的调整目标pod的副本数

阀值:在正常情况下，pod的副本数，以及达到阀值之后，pod的扩容最大数量

3、组件:metrics-server 部署到集群中，对外提供度量的数据

HPA的规则：

1、定义pod时候必须要有资源限制，否则hpa无法进行监控

2、扩容是即时的，只要超过阀值会立刻扩容，不是立刻扩容到最大副本数，会在最大值和最小值波动，如果扩容的数量满足了需求，不会在扩容

3、缩容是缓慢的，如果业务的峰值较高，回收的策略太积极的话，可能会产生业务的崩溃，缩容的速度比较慢的

周期性的获取数据，缩容的机制

HPA的部署运用

进行HPA的部署设置


//在所有 Node 节点上传 metrics-server.tar 镜像包到 /opt 目录
cd /opt/
docker load -i metrics-server.tar#在主master节点上执行
kubectl apply -f components.yaml

HPA伸缩的测试演示

apiVersion: apps/v1
kind: Deployment
metadata:name: centos-testlabels:test: centos1
spec:replicas: 1selector:matchLabels:test: centos1template:metadata:labels:test: centos1spec:containers:- name: centosimage: centos:7command: ["/bin/bash", "-c", "yum -y install epel-release;yum -y install stress;sleep 3600"]resources:limits:cpu: "1"memory: 512Mi
---
apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:name: hpa-centos7
spec:scaleTargetRef:apiVersion: apps/v1kind: Deploymentname: centos-testminReplicas: 1maxReplicas: 5metrics:- type: Resourceresource:name: cputargetAverageUtilization: 50

命名空间资源限

ResourceQuota:命名空间进行资源限制

apiVersion: apps/v1
kind: Deployment
metadata:name: centos-test1namespace: test1labels:test: centos2
spec:replicas: 6selector:matchLabels:test: centos2template:metadata:labels:test: centos2spec:nodeSelector:kubernetes.io/hostname: node01containers:- name: centosimage: centos:7command: ["/bin/bash", "-c", "yum -y install epel-release;yum -y install stress;sleep 3600"]resources:limits:cpu: "1"memory: 512Mi
---
apiVersion: v1
kind: ResourceQuota
metadata:name: ns-resourcenamespace: test1
spec:hard:pods: "10"requests.memory: 1Gilimits.cpu: "4"limits.memory: 2Giconfigmaps: "10"
#在当前这个命名空间能创建最大configmap数量10个persistentvolumeclaims: "4"
#当前命名空间只能使用4个pvcsecrets: "9"
#创建贾母的secret只能9个services: "5"
#创建service个数只能五个services.nodeports: "2"
#创建nodeport类型的svc只能两个

只能在命名空间创建两个service第三个就不创建了因为限制了最多只能创建两个

第二种LimitRange

apiVersion: apps/v1
kind: Deployment
metadata:name: centos-test3namespace: test3labels:test: centos3
spec:replicas: 1selector:matchLabels:test: centos3template:metadata:labels:test: centos3spec:containers:- name: centos3image: centos:7command: ["/bin/bash", "-c", "yum -y install epel-release;yum -y install stress;sleep 3600"]
---apiVersion: v1
kind: LimitRange
metadata:name: test3-limitnamespace: test3
spec:limits:- default:memory: 512Micpu: "1"defaultRequest:memory: 256Micpu: "0.5"type: Container

pod的副本数扩缩容，有两种方式：

1、手动方式kubectl scale deployment nginx1 --replicas=5，kubectl edit,修改yaml文件 apply -f

2、自动扩缩容 hpa 监控指标是cpu和内存没关系

资源限制

pod资源限制

命名空间资源限

ucky-cloud项目--部署在test1的命名空间，如果lucky-cloud不做限制，或者命名空间不做限制，他会依然会沾满所有集群资源

k8s集群部署pod的最大数量:10000

busybox：就是服务最小化的centos 4M

哪些服务会部署在k8s当中

中间件 kafka: 6

redis: 3

选好节点用nodeName固定在一个pod上，扩容之后阀值是否会下降

apiVersion: apps/v1
kind: Deployment
metadata:name: centos-test8labels:test: centos8
spec:replicas: 3selector:matchLabels:test: centos8template:metadata:labels:test: centos8spec:nodeSelector:kubernetes.io/hostname: node01containers:- name: centos8image: centos:7command: ["/bin/bash", "-c", "yum -y install epel-release;yum -y install stress;sleep 3600"]resources:limits:cpu: "2"memory: 512Mi
---
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:name: hpa-centos7
spec:scaleTargetRef:apiVersion: apps/v1kind: Deploymentname: centos-test8minReplicas: 1maxReplicas: 5targetCPUUtilizationPercentage: 50