kubernetes之Hpa

    HorizontalPodAutoscaler, k8s的版本是1.14.　

    需求是这样的，如果应用的cpu使用率到达60%上则自动增加应用数，如果cpu使用率下降则自动将应用数减少。

    先定义Deployment，如下List-1，加上Limit限制资源，好等会做压测的时候自动扩容。

    List-1

apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: {{ template "consumer.fullname" . }}-mjduan
  labels:
    app: {{ template "consumer.name" . }}-mjduan
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ template "consumer.name" . }}-mjduan
  template:
    metadata:
      labels:
        app: {{ template "consumer.name" . }}-mjduan
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        ports:
        - name: http
          containerPort: 8082
          protocol: TCP
        resources:
          requests:
            cpu: 10m
            memory: 100Mi
          limits:
            cpu: 1000m
            memory: 1024Mi

    来看Hpa编排文件，如下List-2，kind是deployment，name的值取List-1中的值。

    List-2

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
    name: {{ template "consumer.fullname" . }}-mjduan-autoscaling
spec:
    scaleTargetRef:
        apiVersion: extensions/v1beta1
        kind: Deployment
        name: {{ template "consumer.name" . }}-mjduan
    minReplicas: 1
    maxReplicas: 8
    targetCPUUtilizationPercentage: 60

    这里ingress就省略不给出了。

    部署后，来看Hpa和pod数，如下List-3和List-4，都是１．

    List-3

mjduan@mjduan:~/.kube$ kubectl get hpa -n test
NAME                                 REFERENCE                           TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
consumer-mjduan-mjduan-autoscaling   Deployment/consumer-mjduan-mjduan   20%/60%   1         8         1          5m57s

    List-4       

mjduan@mjduan:~/.kube$ kubectl get pods -n test
NAME                                      READY   STATUS    RESTARTS   AGE
consumer-mjduan-mjduan-5c6bbff646-k9f4d   1/1     Running   0          7m1s

    现在来用webbench做下压测，让cpu使用率提升

    List-5

./webbench -c 200 -t 60 http://mjduan.rde.x/index/demo?emp_no=091078

    再来看下Hpa和pod数变为了8，随着访问量增多，cpu使用率提升，Hpa自动将pod进行扩容了。

    List-6

#hpa的复制数变为了8
mjduan@mjduan:~/.kube$ kubectl get hpa -n test
NAME                                 REFERENCE                           TARGETS     MINPODS   MAXPODS   REPLICAS   AGE
consumer-mjduan-mjduan-autoscaling   Deployment/consumer-mjduan-mjduan   3670%/60%   1         8         8          7m37s


＃pod数变为了8
mjduan@mjduan:~/.kube$ kubectl get pods -n test
NAME                                      READY   STATUS              RESTARTS   AGE
consumer-mjduan-mjduan-5c6bbff646-425nz   1/1     Running             0          4m15s
consumer-mjduan-mjduan-5c6bbff646-7wb4l   1/1     Running             0          4m
consumer-mjduan-mjduan-5c6bbff646-d477h   1/1     Running             0          4m15s
consumer-mjduan-mjduan-5c6bbff646-k9f4d   1/1     Running             0          11m
consumer-mjduan-mjduan-5c6bbff646-pc4xh   1/1     Running             0          4m
consumer-mjduan-mjduan-5c6bbff646-q56ml   1/1     Running             0          4m
consumer-mjduan-mjduan-5c6bbff646-swc88   0/1     ContainerCreating   0          4m
consumer-mjduan-mjduan-5c6bbff646-vxqfb   1/1     Running             0          4m15s

    再隔断时间，来看hpa和pod数，变少了，因为访问量减少，k8s自动按Hpa的规则将pod减少了。

    List-7

#复制数变为了5
mjduan@mjduan:~/.kube$ kubectl get hpa -n test
NAME                                 REFERENCE                           TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
consumer-mjduan-mjduan-autoscaling   Deployment/consumer-mjduan-mjduan   25%/60%   1         8         5          15m

#pod数在减少
mjduan@mjduan:~/.kube$ kubectl get pods -n test
NAME                                      READY   STATUS        RESTARTS   AGE
consumer-mjduan-mjduan-5c6bbff646-425nz   1/1     Running       0          8m8s
consumer-mjduan-mjduan-5c6bbff646-7wb4l   1/1     Terminating   0          7m53s
consumer-mjduan-mjduan-5c6bbff646-d477h   1/1     Running       0          8m8s
consumer-mjduan-mjduan-5c6bbff646-k9f4d   1/1     Running       0          15m
consumer-mjduan-mjduan-5c6bbff646-pc4xh   1/1     Running       0          7m53s
consumer-mjduan-mjduan-5c6bbff646-q56ml   1/1     Terminating   0          7m53s
consumer-mjduan-mjduan-5c6bbff646-vxqfb   1/1     Running       0          8m8s

 Reference

1. https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/
2. https://blog.csdn.net/mailjoin/article/details/79679944