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HPA全称HorizontalPodAutoscaler Pod水平自动扩缩容#xff0c;Kubernetes控制器HPA是一种用于自动调整Pod数量的控制器。它可以根据资源使用情况自动增加或减少Pod的数量#xff0c;以确保应用程序的高可用性和性能。HPA可以根据CPU使用率或自定义指标来进行调整…简述
HPA全称HorizontalPodAutoscaler Pod水平自动扩缩容Kubernetes控制器HPA是一种用于自动调整Pod数量的控制器。它可以根据资源使用情况自动增加或减少Pod的数量以确保应用程序的高可用性和性能。HPA可以根据CPU使用率或自定义指标来进行调整例如请求延迟或网络吞吐量
Pod 水平自动扩缩中文文档
工作原理
HPA一般通过指示工作负载资源如Deployment、StatefulSet 或其他类似资源进行扩缩容对于像DaemonSet这种无法扩缩的对象不适用
使用之前我们先安装metrics-server它可以用来收集集群中的资源使用情况。hpa通过metrics-server的api获取这些数据然后进行扩缩容的副本计算得到目标副本数量如果与当前副本数不相同就通过副本控制器进行scale操作
metrics-server的yaml清单获取 metrics-server
安装完后使用top命令查看
[rootmaster hpa]# kubectl top node
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
master 124m 6% 2508Mi 69%
node01 59m 2% 1941Mi 54%
node02 53m 2% 2010Mi 55%hpa资源文件清单
apiVersion: autoscaling/v2beta1 # 使用autoscaling/v2beta1版本的HPA API
kind: HorizontalPodAutoscaler # 定义HPA控制器
metadata:name: example-hpa # HPA资源的名称namespace: default # HPA资源所在的命名空间
spec:scaleTargetRef:apiVersion: apps/v1kind: Deployment # 所有Pod数量将根据该Deployment对象的副本数量进行自动缩放name: example-deployment # HPA将控制的Deployment对象名称minReplicas: 2 # 最小Pod数量maxReplicas: 10 # 最大Pod数量metrics:- type: Resource # 使用资源指标类型resource:name: cpu # 使用CPU使用率作为资源指标target:type: Utilization # 使用CPU利用率作为度量标准averageUtilization: 50 # 目标CPU利用率达到该利用率时触发自动扩缩容- type: Object # 使用对象指标类型object:metricName: example_http_requests_total # 自定义指标名称target:type: Value # 目标值类型可以是Value或AverageValuevalue: 100 # 触发自动扩缩容的目标值describedObject:apiVersion: v1kind: Service # 该对象指标作用于Service对象name: example-service # 该对象指标作用于的Service对象名称
上面的自定义指标配置不会再本章讲解
案例
下面以一个案例来解释hpa的使用
使用hpa来控制deployment自动扩缩容当pod资源平均使用率达到3%时进行扩容
创建一个Deployment
apiVersion: apps/v1
kind: Deployment
metadata:name: nginx
spec:selector:matchLabels:app: nginx-hpatemplate:metadata:labels:app: nginx-hpaspec:containers:- name: nginximage: nginx:1.17.1ports:- containerPort: 80protocol: TCPresources:requests:memory: 50Micpu: 100m# 创建deployment
[rootmaster hpa]# kubectl create -f hpa-deploy.yaml
deployment.apps/nginx created
# 记录下IP后面压测用到 10.244.2.104
[rootmaster hpa]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-659b6d57bd-5tbg2 1/1 Running 0 10s 10.244.2.104 node02 none none创建HPA 最小副本数1最大10 autoscaling/v1版本
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:name: hpa
spec:minReplicas: 1maxReplicas: 10targetCPUUtilizationPercentage: 3scaleTargetRef:apiVersion: apps/v1kind: Deploymentname: nginxautoscaling/v2版本
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:name: hpa
spec:minReplicas: 1maxReplicas: 10scaleTargetRef:apiVersion: apps/v1kind: Deploymentname: nginxmetrics:- type: Resourceresource:name: cputarget:type: UtilizationaverageUtilization: 3# 创建hpa
[rootmaster hpa]# kubectl create -f hpa.yaml
horizontalpodautoscaler.autoscaling/hpa created# 查看hpa还没有完全启动完
[rootmaster hpa]# kubectl get hpa
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
hpa Deployment/nginx unknown/3% 1 10 0 6s# 再次查看hpa启动完成 目前资源使用率 0%
[rootmaster hpa]# kubectl get hpa
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
hpa Deployment/nginx 0%/3% 1 10 1 20s使用ab工具进行压测没有该工具需要安装 httpd-tools
# 安装 httpd-tools
yum -y install httpd-tools# ab工具可以模拟多个用户并发请求向Web服务器发送请求并统计响应时间和处理请求数量等信息
# ab -n requests -c concurrency url
# 参数说明
#- requests总请求数例如-n 1000。
#- concurrency并发请求数例如-c 10。
#- url测试的URL地址。
压测
ab -n 10000 -c 1000 http://10.244.2.104/观察压测结果
# 监听hpa 发现压测中cpu达到60% 后面又降回去了
[rootmaster ~]# kubectl get hpa -w
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
hpa Deployment/nginx 0%/3% 1 10 1 7m30s
hpa Deployment/nginx 60%/3% 1 10 1 9m1s
hpa Deployment/nginx 0%/3% 1 10 4 9m16s
hpa Deployment/nginx 0%/3% 1 10 8 9m31s
hpa Deployment/nginx 0%/3% 1 10 10 9m46s# 监听Pod 一开始只有一个nginx-659b6d57bd-5tbg2 运行了8m47s压测后又创建了9个Pod观察ContainerCreating数量
[rootmaster hpa]# kubectl get pod -w
NAME READY STATUS RESTARTS AGE
nginx-659b6d57bd-5tbg2 1/1 Running 0 8m47s
nginx-659b6d57bd-47f98 0/1 Pending 0 0s
nginx-659b6d57bd-47f98 0/1 Pending 0 0s
nginx-659b6d57bd-qs4tr 0/1 Pending 0 0s
nginx-659b6d57bd-tvnmp 0/1 Pending 0 0s
nginx-659b6d57bd-tvnmp 0/1 Pending 0 0s
nginx-659b6d57bd-qs4tr 0/1 Pending 0 0s
nginx-659b6d57bd-47f98 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-qs4tr 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-tvnmp 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-47f98 1/1 Running 0 1s
nginx-659b6d57bd-tvnmp 1/1 Running 0 1s
nginx-659b6d57bd-qs4tr 1/1 Running 0 2s
nginx-659b6d57bd-mccdl 0/1 Pending 0 0s
nginx-659b6d57bd-mccdl 0/1 Pending 0 0s
nginx-659b6d57bd-w9r46 0/1 Pending 0 0s
nginx-659b6d57bd-498c2 0/1 Pending 0 0s
nginx-659b6d57bd-w9r46 0/1 Pending 0 0s
nginx-659b6d57bd-498c2 0/1 Pending 0 0s
nginx-659b6d57bd-mccdl 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-nvhgh 0/1 Pending 0 0s
nginx-659b6d57bd-nvhgh 0/1 Pending 0 0s
nginx-659b6d57bd-w9r46 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-498c2 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-nvhgh 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-mccdl 1/1 Running 0 1s
nginx-659b6d57bd-498c2 1/1 Running 0 1s
nginx-659b6d57bd-w9r46 1/1 Running 0 1s
nginx-659b6d57bd-nvhgh 1/1 Running 0 1s
nginx-659b6d57bd-gq6dc 0/1 Pending 0 0s
nginx-659b6d57bd-gq6dc 0/1 Pending 0 0s
nginx-659b6d57bd-k7vdz 0/1 Pending 0 0s
nginx-659b6d57bd-k7vdz 0/1 Pending 0 0s
nginx-659b6d57bd-gq6dc 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-k7vdz 0/1 ContainerCreating 0 0s
nginx-659b6d57bd-gq6dc 1/1 Running 0 1s
nginx-659b6d57bd-k7vdz 1/1 Running 0 1s# 观察deploy看到副本数量也是达到10个
[rootmaster ~]# kubectl get deploy -w
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 1/1 1 1 9m19s
nginx 1/4 1 1 10m
nginx 1/4 1 1 10m
nginx 1/4 1 1 10m
nginx 1/4 4 1 10m
nginx 2/4 4 2 10m
nginx 3/4 4 3 10m
nginx 4/4 4 4 10m
nginx 4/8 4 4 10m
nginx 4/8 4 4 10m
nginx 4/8 4 4 10m
nginx 4/8 8 4 10m
nginx 5/8 8 5 10m
nginx 6/8 8 6 10m
nginx 7/8 8 7 10m
nginx 8/8 8 8 10m
nginx 8/10 8 8 11m
nginx 8/10 8 8 11m
nginx 8/10 8 8 11m
nginx 8/10 10 8 11m
nginx 9/10 10 9 11m
nginx 10/10 10 10 11m压测完后缩容 大概等待五分钟会看到缩容效果
# deploy的pod副本书已经缩为1个
[rootmaster ~]# kubectl get deploy -w
nginx 10/10 10 10 11m
nginx 10/1 10 10 16m
nginx 10/1 10 10 16m
nginx 1/1 1 1 16m# 观察Pod开始逐步缩容 Pod停止Terminating
[rootmaster ~]# kubectl get pod -w
nginx-659b6d57bd-mccdl 1/1 Terminating 0 5m45s
nginx-659b6d57bd-47f98 1/1 Terminating 0 6m
nginx-659b6d57bd-w9r46 1/1 Terminating 0 5m45s
nginx-659b6d57bd-gq6dc 1/1 Terminating 0 5m30s
nginx-659b6d57bd-nvhgh 1/1 Terminating 0 5m45s
nginx-659b6d57bd-k7vdz 1/1 Terminating 0 5m30s
nginx-659b6d57bd-498c2 1/1 Terminating 0 5m45s
nginx-659b6d57bd-qs4tr 1/1 Terminating 0 6m
nginx-659b6d57bd-tvnmp 1/1 Terminating 0 6m
nginx-659b6d57bd-498c2 0/1 Terminating 0 5m46s
nginx-659b6d57bd-498c2 0/1 Terminating 0 5m46s
nginx-659b6d57bd-498c2 0/1 Terminating 0 5m46s
nginx-659b6d57bd-k7vdz 0/1 Terminating 0 5m31s
nginx-659b6d57bd-k7vdz 0/1 Terminating 0 5m31s
nginx-659b6d57bd-k7vdz 0/1 Terminating 0 5m31s
nginx-659b6d57bd-nvhgh 0/1 Terminating 0 5m46s
nginx-659b6d57bd-nvhgh 0/1 Terminating 0 5m46s
nginx-659b6d57bd-nvhgh 0/1 Terminating 0 5m46s
nginx-659b6d57bd-47f98 0/1 Terminating 0 6m1s
nginx-659b6d57bd-47f98 0/1 Terminating 0 6m2s
nginx-659b6d57bd-47f98 0/1 Terminating 0 6m2s
nginx-659b6d57bd-gq6dc 0/1 Terminating 0 5m32s
nginx-659b6d57bd-gq6dc 0/1 Terminating 0 5m32s
nginx-659b6d57bd-gq6dc 0/1 Terminating 0 5m32s
nginx-659b6d57bd-mccdl 0/1 Terminating 0 5m47s
nginx-659b6d57bd-mccdl 0/1 Terminating 0 5m47s
nginx-659b6d57bd-mccdl 0/1 Terminating 0 5m47s
nginx-659b6d57bd-qs4tr 0/1 Terminating 0 6m2s
nginx-659b6d57bd-w9r46 0/1 Terminating 0 5m47s
nginx-659b6d57bd-qs4tr 0/1 Terminating 0 6m2s
nginx-659b6d57bd-qs4tr 0/1 Terminating 0 6m2s
nginx-659b6d57bd-w9r46 0/1 Terminating 0 5m47s
nginx-659b6d57bd-w9r46 0/1 Terminating 0 5m47s
nginx-659b6d57bd-tvnmp 0/1 Terminating 0 6m3s
nginx-659b6d57bd-tvnmp 0/1 Terminating 0 6m3s
nginx-659b6d57bd-tvnmp 0/1 Terminating 0 6m3s# 只有一个Pod
[rootmaster ~]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-659b6d57bd-5tbg2 1/1 Running 0 18m欢迎关注学习不迷路
