Horizontal Pod Autoscaler（HPA）

• 环境
• 接口类型
• 创建HPA deployment
• 创建HPA对象
• 模拟触发自动扩缩容

环境

• 必须安装metrics-server或其他自定义metrics-server
• 必须配置requests参数
• 不能扩容无法缩放的对象，比如DaemonSet

接口类型

• HPA v1为稳定版自动水平伸缩，只支持CPU指标
• V2为beta版本，分为v2beta1(支持CPU、内存和自定义指标)
• v2beta2(支持CPU、内存、自定义指标Custom和额外指标ExternalMetrics)

$ kubectl get apiservices |grep autoscal
v1.autoscaling                         Local                        True        88d
v2beta1.autoscaling                    Local                        True        88d
v2beta2.autoscaling                    Local                        True   

创建HPA deployment

[root@k8s-master01 ~]$ kubectl create deployment hpa-nginx --image=registry.cn-beijing.aliyuncs.com/dotbalo/nginx  --dry-run=client -oyaml > hpa-nginx.yaml
[root@k8s-master01 ~]$ vim hpa-nginx.yaml 

##container下设置pod资源
    spec:
      containers:
      - image: registry.cn-beijing.aliyuncs.com/dotbalo/nginx
        name: nginx
        resources:
          requests:
            cpu: 10m
#创建deployment
[root@k8s-master01 ~]$ kubectl create -f hpa-nginx.yaml 
deployment.apps/hpa-nginx created
[root@k8s-master01 ~]$ kubectl  top po
NAME                         CPU(cores)   MEMORY(bytes)   
busybox                      0m           0Mi             
hpa-nginx-58ddb65c8d-5cs9h   1m           6Mi             

创建HPA对象

最小副本1，最大副本10，cpu超过10%自动扩容，小于10%自动缩容

[root@k8s-master01 ~]$ kubectl autoscale deployment hpa-nginx --cpu-percent=10 --min=1 --max=10
horizontalpodautoscaler.autoscaling/hpa-nginx autoscaled
[root@k8s-master01 ~]$ kubectl get hpa
NAME        REFERENCE              TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
hpa-nginx   Deployment/hpa-nginx   <unknown>/10%   1         10        0          6s
#等待一会设置成功TARGETS状态改变
[root@k8s-master01 ~]$ kubectl get hpa
NAME        REFERENCE              TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
hpa-nginx   Deployment/hpa-nginx   0%/10%    1         10        1          8m24s

模拟触发自动扩缩容

暴露服务端口：
$ kubectl expose deployment hpa-nginx --port=80
设置循环请求：
$ while true; do wget -q -O- http:// 172.25.244.241 > /dev/null; done

#此时cpu飙升，触发扩容
[root@k8s-master01 ~]$ kubectl top po
NAME                         CPU(cores)   MEMORY(bytes)   
busybox                      0m           0Mi             
hpa-nginx-58ddb65c8d-5cs9h   78m          6Mi
[root@k8s-master01 ~]$ kubectl get hpa
NAME        REFERENCE              TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
hpa-nginx   Deployment/hpa-nginx   79%/10%   1         10        10         15m     
[root@k8s-master01 ~]$ kubectl get po
NAME                         READY   STATUS              RESTARTS   AGE
busybox                      1/1     Running             110        88d
hpa-nginx-58ddb65c8d-4pp59   1/1     Running             0          11s
hpa-nginx-58ddb65c8d-4znxs   0/1     ContainerCreating   0          26s
hpa-nginx-58ddb65c8d-5cs9h   1/1     Running             0          17m
hpa-nginx-58ddb65c8d-627f4   1/1     Running             0          11s
hpa-nginx-58ddb65c8d-97kbf   0/1     ContainerCreating   0          11s
hpa-nginx-58ddb65c8d-cjblq   0/1     ContainerCreating   0          11s
hpa-nginx-58ddb65c8d-ds758   1/1     Running             0          26s
hpa-nginx-58ddb65c8d-t44gh   1/1     Running             0          26s


#停止循环，自动缩容
[root@k8s-master01 ~]$ kubectl get po -l  app=hpa-nginx -w
NAME                         READY   STATUS    RESTARTS   AGE
hpa-nginx-58ddb65c8d-4pp59   1/1     Running   0          6m33s
hpa-nginx-58ddb65c8d-4znxs   1/1     Running   0          6m48s
hpa-nginx-58ddb65c8d-5cs9h   1/1     Running   0          23m
hpa-nginx-58ddb65c8d-627f4   1/1     Running   0          6m33s
hpa-nginx-58ddb65c8d-97kbf   1/1     Running   0          6m33s
hpa-nginx-58ddb65c8d-cjblq   1/1     Running   0          6m33s
hpa-nginx-58ddb65c8d-ds758   1/1     Running   0          6m48s
hpa-nginx-58ddb65c8d-p7dmv   1/1     Running   0          6m17s
hpa-nginx-58ddb65c8d-pkdf4   1/1     Running   0          6m17s
hpa-nginx-58ddb65c8d-t44gh   1/1     Running   0          6m48s
hpa-nginx-58ddb65c8d-97kbf   1/1     Terminating   0          9m40s
hpa-nginx-58ddb65c8d-cjblq   1/1     Terminating   0          9m40s
hpa-nginx-58ddb65c8d-ds758   1/1     Terminating   0          9m55s
hpa-nginx-58ddb65c8d-pkdf4   1/1     Terminating   0          9m24s
hpa-nginx-58ddb65c8d-4pp59   1/1     Terminating   0          9m40s
hpa-nginx-58ddb65c8d-627f4   1/1     Terminating   0          9m40s
[root@k8s-master01 ~]$ kubectl get po
NAME                         READY   STATUS    RESTARTS   AGE
busybox                      1/1     Running   110        88d
hpa-nginx-58ddb65c8d-5cs9h   1/1     Running   0          29m