一、自动伸缩
1、启动
[root@k8s-master ~]# kubectl autoscale deployment nginx-deployment --max=8 --min=2 --cpu-percent=80deployment "nginx-deployment" autoscaled
2、查看创建
[root@k8s-master ~]# kubectl get allNAME ?????????????????????DESIRED ??CURRENT ??UP-TO-DATE ??AVAILABLE ??AGEdeploy/nginx-deployment ??2 ????????2 ????????2 ???????????2 ??????????13hNAME ??????????????????REFERENCE ????????????????????TARGET ???CURRENT ??MINPODS ??MAXPODS ??AGEhpa/nginx-deployment ??Deployment/nginx-deployment ??80% ??????0% ???????2 ????????8 ????????17sNAME ????????????CLUSTER-IP ?????EXTERNAL-IP ??PORT(S) ???????AGEsvc/kubernetes ??10.254.0.1 ?????<none> ???????443/TCP ???????2dsvc/nginx ???????10.254.145.15 ??<nodes> ??????80:32000/TCP ??1dNAME ????????????????????????????DESIRED ??CURRENT ??READY ????AGErs/nginx-deployment-2950479891 ??0 ????????0 ????????0 ????????13hrs/nginx-deployment-3113009173 ??2 ????????2 ????????2 ????????13hNAME ??????????????????????????????????READY ????STATUS ???RESTARTS ??AGEpo/nginx-deployment-3113009173-h5plc ??1/1 ??????Running ??0 ?????????17spo/nginx-deployment-3113009173-vckhg ??1/1 ??????Running ??1 ?????????13h
3、修改副本数为1
[root@k8s-master ~]# kubectl edit deployment nginx-deployment修改为1replicas: 1deployment "nginx-deployment" edited[root@k8s-master ~]# kubectl get allNAME ?????????????????????DESIRED ??CURRENT ??UP-TO-DATE ??AVAILABLE ??AGEdeploy/nginx-deployment ??1 ????????1 ????????1 ???????????1 ??????????13hNAME ????????????CLUSTER-IP ?????EXTERNAL-IP ??PORT(S) ???????AGEsvc/kubernetes ??10.254.0.1 ?????<none> ???????443/TCP ???????2dsvc/nginx ???????10.254.145.15 ??<nodes> ??????80:32000/TCP ??1dNAME ????????????????????????????DESIRED ??CURRENT ??READY ????AGErs/nginx-deployment-2950479891 ??0 ????????0 ????????0 ????????13hrs/nginx-deployment-3113009173 ??1 ????????1 ????????1 ????????13hNAME ??????????????????????????????????READY ????STATUS ???RESTARTS ??AGEpo/nginx-deployment-3113009173-vckhg ??1/1 ??????Running ??1 ?????????13h
二、hpa伸缩
1、编辑horizontalpodautoscaler 文件
[root@k8s-master ~]# kubectl get horizontalpodautoscaler NAME ??????????????REFERENCE ????????????????????TARGET ???CURRENT ??MINPODS ??MAXPODS ??AGEnginx-deployment ??Deployment/nginx-deployment ??80% ??????0% ???????2 ????????8 ????????1m# Please edit the object below. Lines beginning with a ‘#‘ will be ignored,# and an empty file will abort the edit. If an error occurs while saving this file will be# reopened with the relevant failures.#apiVersion: autoscaling/v1kind: HorizontalPodAutoscalermetadata: ?creationTimestamp: 2019-01-22T01:00:02Z ?name: nginx-deployment ?namespace: default ?resourceVersion: "41194" ?selfLink: /apis/autoscaling/v1/namespaces/default/horizontalpodautoscalers/nginx-deployment ?uid: 0c897472-1de1-11e9-9773-000c292bd9e1spec: ?maxReplicas: 8 ?minReplicas: 2 ?scaleTargetRef: ???apiVersion: extensions/v1beta1 ???kind: Deployment ???name: nginx-deployment ?targetCPUUtilizationPercentage: 80status: ?currentCPUUtilizationPercentage: 0 ?currentReplicas: 2 ?desiredReplicas: 2 ?lastScaleTime: 2019-01-22T01:00:02Z
2、修改副本为1
[root@k8s-master ~]# kubectl edit deployment nginx-deployment ?replicas: 1deployment "nginx-deployment" edited[root@k8s-master ~]# kubectl get allNAME ?????????????????????DESIRED ??CURRENT ??UP-TO-DATE ??AVAILABLE ??AGEdeploy/nginx-deployment ??2 ????????2 ????????2 ???????????2 ??????????13hNAME ??????????????????REFERENCE ????????????????????TARGET ???CURRENT ??MINPODS ??MAXPODS ??AGEhpa/nginx-deployment ??Deployment/nginx-deployment ??80% ??????0% ???????2 ????????8 ????????6mNAME ????????????CLUSTER-IP ?????EXTERNAL-IP ??PORT(S) ???????AGEsvc/kubernetes ??10.254.0.1 ?????<none> ???????443/TCP ???????2dsvc/nginx ???????10.254.145.15 ??<nodes> ??????80:32000/TCP ??1dNAME ????????????????????????????DESIRED ??CURRENT ??READY ????AGErs/nginx-deployment-2950479891 ??0 ????????0 ????????0 ????????13hrs/nginx-deployment-3113009173 ??2 ????????2 ????????2 ????????13hNAME ??????????????????????????????????READY ????STATUS ???RESTARTS ??AGEpo/nginx-deployment-3113009173-9hlq1 ??1/1 ??????Running ??0 ?????????2spo/nginx-deployment-3113009173-vckhg ??1/1 ??????Running ??1 ?????????13h
明明修改为1，怎么还有2个？是因为hpa如下配置
spec: ?maxReplicas: 8 ?minReplicas: 2
3、修改副本数为5
[root@k8s-master ~]# kubectl edit hpa nginx-deployment修改：spec: ?maxReplicas: 8 ?minReplicas: 5horizontalpodautoscaler "nginx-deployment" edited[root@k8s-master ~]# kubectl get allNAME ?????????????????????DESIRED ??CURRENT ??UP-TO-DATE ??AVAILABLE ??AGEdeploy/nginx-deployment ??5 ????????5 ????????5 ???????????2 ??????????13hNAME ??????????????????REFERENCE ????????????????????TARGET ???CURRENT ??MINPODS ??MAXPODS ??AGEhpa/nginx-deployment ??Deployment/nginx-deployment ??80% ??????0% ???????5 ????????8 ????????8mNAME ????????????CLUSTER-IP ?????EXTERNAL-IP ??PORT(S) ???????AGEsvc/kubernetes ??10.254.0.1 ?????<none> ???????443/TCP ???????2dsvc/nginx ???????10.254.145.15 ??<nodes> ??????80:32000/TCP ??1dNAME ????????????????????????????DESIRED ??CURRENT ??READY ????AGErs/nginx-deployment-2950479891 ??0 ????????0 ????????0 ????????13hrs/nginx-deployment-3113009173 ??5 ????????5 ????????2 ????????13hNAME ??????????????????????????????????READY ????STATUS ?????????????RESTARTS ??AGEpo/nginx-deployment-3113009173-97l9c ??0/1 ??????ContainerCreating ??0 ?????????2spo/nginx-deployment-3113009173-9hlq1 ??1/1 ??????Running ????????????0 ?????????2mpo/nginx-deployment-3113009173-qq4h8 ??0/1 ??????ContainerCreating ??0 ?????????2spo/nginx-deployment-3113009173-sfp8z ??0/1 ??????ContainerCreating ??0 ?????????2spo/nginx-deployment-3113009173-vckhg ??1/1 ??????Running ????????????1 ?????????13h
看到自动伸缩的过程了吧！
三、HAP-deployment-rs-rc-pod调用原理
1、什么是hpa
Horizontal Pod Autoscaling可以根据CPU使用率或应用自定义metrics自动扩展Pod数量（支持replication controller、deployment和replica set）。
- 控制管理器每隔30s（可以通过–horizontal-pod-autoscaler-sync-period修改）查询metrics的资源使用情况
- 支持三种metrics类型
- 预定义metrics（比如Pod的CPU）以利用率的方式计算
- 自定义的Pod metrics，以原始值（raw value）的方式计算
- 自定义的object metrics
- 支持两种metrics查询方式：Heapster和自定义的REST API
- 支持多metrics
客户端;
通过kubectl创建一个horizontalPodAutoscaler对象，并存储到etcd中
服务端：
api server:负责接受创建hpa对象，然后存入etcd
hpa controler和其他的controler类似，每30s同步一次，将已经创建的hpa进行一次管理（从heapster获取监控数据，查看是否需要scale, controler的store中就保存着从始至终创建出来的hpa，当做一个缓存），watch hpa有变化也会运行。从heapster中获取scale数据，和hpa对比，计算cup利用率等信息，然后重新调整scale。根据hpa.Spec.ScaleTargetRef.Kind（例如Deployment，然后deployment控制器在调整pod数量），调整其值，发送到apiserver存储到etcd，然后更新hpa到etcd.
2、示例
# 创建pod和service$ kubectl run php-apache --image=gcr.io/google_containers/hpa-example --requests=cpu=200m --expose --port=80service "php-apache" createddeployment "php-apache" created# 创建autoscaler$ kubectl autoscale deployment php-apache --cpu-percent=50 --min=1 --max=10deployment "php-apache" autoscaled$ kubectl get hpaNAME ????????REFERENCE ????????????????????TARGET ???CURRENT ??MINPODS ??MAXPODS ??AGEphp-apache ??Deployment/php-apache/scale ??50% ??????0% ???????1 ????????10 ???????18s# 增加负载$ kubectl run -i --tty load-generator --image=busybox /bin/shHit enter for command prompt$ while true; do wget -q -O- http://php-apache.default.svc.cluster.local; done# 过一会就可以看到负载升高了$ kubectl get hpaNAME ????????REFERENCE ????????????????????TARGET ???CURRENT ??MINPODS ??MAXPODS ??AGEphp-apache ??Deployment/php-apache/scale ??50% ??????305% ?????1 ????????10 ???????3m# autoscaler将这个deployment扩展为7个pod$ kubectl get deployment php-apacheNAME ????????DESIRED ??CURRENT ??UP-TO-DATE ??AVAILABLE ??AGEphp-apache ??7 ????????7 ????????7 ???????????7 ??????????19m# 删除刚才创建的负载增加pod后会发现负载降低，并且pod数量也自动降回1个$ kubectl get hpaNAME ????????REFERENCE ????????????????????TARGET ???CURRENT ??MINPODS ??MAXPODS ??AGEphp-apache ??Deployment/php-apache/scale ??50% ??????0% ???????1 ????????10 ???????11m$ kubectl get deployment php-apacheNAME ????????DESIRED ??CURRENT ??UP-TO-DATE ??AVAILABLE ??AGEphp-apache ??1 ????????1 ????????1 ???????????1 ??????????27m
3、关系原理图
4、小结
1、首先最底层的资源永远都是pod
2、比pod高级一点的资源叫rc副本控制器
3、在pod上面有一个高级的rs
4、那谁来管理rs呢？是deployment
5、HPA自动管理deployment，deployment设置为1，HPA最低设置为3，deployment这就会被自动设计为3个
kubernetes云平台管理实战：HPA水平自动伸缩（十一）
原文地址：https://www.cnblogs.com/luoahong/p/10303077.html