Kubernetes弹性伸缩 – Tech 学习之路

K8s弹性伸缩需要附加组件heapster监控。

一、安装Heapster监控

1. 工作原理

2. 部署服务

step 1 上传、导入镜像，并为镜像添加标签

heapster服务
提取码：tdi6

[root@k8s-registry ~]# for i in `ls docker_heapster*.tar.gz`; do docker load -i $i; done
......
[root@k8s-registry ~]# docker tag docker.io/kubernetes/heapster_grafana:v2.6.0 10.0.0.140:5000/heapster_grafana:v2.6.0
[root@k8s-registry ~]# docker tag docker.io/kubernetes/heapster_influxdb:v0.5 10.0.0.140:5000/heapster_influxdb:v0.5
[root@k8s-registry ~]# docker tag docker.io/kubernetes/heapster:canary 10.0.0.140:5000/heapster:canary
[root@k8s-registry ~]# docker push 10.0.0.140:5000/heapster:canary
......
[root@k8s-registry ~]# docker push 10.0.0.140:5000/heapster_influxdb:v0.5 
......
[root@k8s-registry ~]# docker push 10.0.0.140:5000/heapster_grafana:v2.6.0 
......

step 2 创建heapster配置文件并应用

# heapster服务Deployment资源
[root@k8s-master ~/k8s_yaml/heapster]# cat heapster-controller.yml 
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    k8s-app: heapster
    name: heapster
    version: v6
  name: heapster
  namespace: kube-system
spec:
  replicas: 1
  template:
    metadata:
      labels:
        k8s-app: heapster
        version: v6
    spec:
      containers:
      - name: heapster
        image: 10.0.0.140:5000/heapster:canary
        imagePullPolicy: IfNotPresent 
        #Always/IfNotPresent/Never
        command:
        - /heapster
        - --source=kubernetes:http://10.0.0.110:10000?inClusterConfig=false
        - --sink=influxdn:http://monitoring-influxdb:8086

# influxdb服务和Grafana服务Deployment资源
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
     name: influxGrafana
  name: influx-grafana
  namespace: kube-system
spec:
  replicas: 1
  template:
    metadata:
      labels: 
        name: influxGrafana
    spec:
      containers:
      - name: influxdb
        image: 10.0.0.140:5000/heapster_influxdb:v0.5
        volumeMounts:
        - mountPath: /data
          name: influxdb-storage
      - name: grafana
        image: 10.0.0.140:5000/heapster_grafana:v2.6.0
        env:
          - name: INFLUXDB_SERVICE_URL
            value: http://monitoring-influxdb:8086
            # The following env variables are required to make Grafana accessible via 
            # the kubernetes api-server proxy. On production clusters, we recommend 
            # removing these env variables, setup auth for grafana, and expos the grafana 
            # service using a LoadBalancer or a public IP.
          - name: GF_AUTH_BASIC_ENABLED
            value: "false"
          - name: GF_AUTH_ANONYMOUS_ENABLED
            value: "true"
          - name: GF_AUTH_ANONYMOUS_ORG_ROLE
            value: Admin
          - name: GF_SERVER_ROOT_URL
            value: /api/v1/proxy/namespaces/kube-system/services/monitoring-grafana/
        volumeMounts:
        - mountPath: /var
          name: grafana-storage
      volumes:
      - name: influxdb-storage
        emptyDir: {}
      - name: grafana-storage
        emptyDir: {}

# heapster服务Service资源
apiVersion: v1
kind: Service
metadata:
  labels:
    kubernetes.io/cluster-service: 'true'
    kubernetes.io/name: Heapster
  name: heapster
  namespace: kube-system
spec:
  ports:
  - port: 80
    targetPort: 8082
  selector:
    k8s-app: heapster

# influxdb服务Service资源
apiVersion: v1
kind: Service
metadata:
  labels: null
  name: monitoring-influxdb
  namespace: kube-system
spec:
  ports:
  - name: http
    port: 8083
    targetPort: 8083
  - name: api
    port: 8086
    targetPort: 8086
  selector:
    name: influxGrafana

# grafana服务Service资源
apiVersion: v1
kind: Service
metadata:
  labels:
    kubernetes.io/cluster-service: 'true'
    kubernetes.io/name: monitoring-grafana
  name: monitoring-grafana
  namespace: kube-system
spec:
  # In a production setup, we recommend accessing Grafana through an external Loadbalancer 
  # or through a public IP. 
  # type: LoadBalancer
  ports: 
  - port: 80
    targetPort: 3000
  selector:
    name: influxGrafana

[root@k8s-master ~]# mkdir k8s_yaml/heapster && cd k8s_yaml/heapster
[root@k8s-master ~/k8s_yaml/heapster]# kubectl -s http://10.0.0.110:10000 create -f .
service "monitoring-grafana" created
deployment "heapster" created
service "heapster" created
deployment "influx-grafana" created
service "monitoring-influxdb" created
[root@k8s-master ~/k8s_yaml/heapster]# kubectl -s http://10.0.0.110:10000 get svc -o wide -n kube-system
NAME                   CLUSTER-IP       EXTERNAL-IP   PORT(S)             AGE       SELECTOR
heapster               10.100.131.98    <none>        80/TCP              6m        k8s-app=heapster
kube-dns               10.100.1.1       <none>        53/UDP,53/TCP       237d      k8s-app=kube-dns
kubernetes-dashboard   10.100.154.244   <none>        80/TCP              23h       k8s-app=kubernetes-dashboard
monitoring-grafana     10.100.250.83    <none>        80/TCP              6m        name=influxGrafana
monitoring-influxdb    10.100.7.71      <none>        8083/TCP,8086/TCP   6m        name=influxGrafana
[root@k8s-master ~/k8s_yaml/heapster]# kubectl -s http://10.0.0.110:10000 get pod -n kube-system -o wide --show-labels
NAME                                           READY     STATUS    RESTARTS   AGE       IP             NODE         LABELS
heapster-3438138036-n319x                      1/1       Running   0          31m       192.168.56.3   10.0.0.120   k8s-app=heapster,pod-template-hash=3438138036,version=v6
influx-grafana-2235217320-hbvqj                2/2       Running   0          31m       192.168.56.4   10.0.0.120   name=influxGrafana,pod-template-hash=2235217320
kube-dns-2134347918-7lz53                      4/4       Running   0          17m       192.168.45.3   10.0.0.130   k8s-app=kube-dns,pod-template-hash=2134347918
kube-dns-2134347918-90f80                      4/4       Running   0          17m       192.168.45.2   10.0.0.130   k8s-app=kube-dns,pod-template-hash=2134347918
kubernetes-dashboard-latest-2686154000-77357   1/1       Running   1          3h        192.168.56.2   10.0.0.120   k8s-app=kubernetes-dashboard,kubernetes.io/cluster-service=true,pod-template-hash=2686154000,version=latest

二、部署弹性伸缩

1. 工作原理

hpa: Horizontal Pod Autoscaler

2. 创建hpa资源(Shell方式)

# 准备环境
[root@k8s-master ~/k8s_yaml/heapster]# cd ../Deployment/
[root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.1l 
deployment "nginx" created
[root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.1
NAME         CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   10.100.0.1   <none>        443/TCP   3h
[root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 expose deploy nginx --name=svc-nginx --type=NodePort --port=80 --target-port=80 
service "svc-nginx" exposed
[root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 get deployment -o wide --show-labels
NAME      DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE       LABELS
nginx     4         4         4            4           4m        app=nginx
[root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 get svc -o wide
NAME         CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE       SELECTOR
kubernetes   10.100.0.1       <none>        443/TCP        3h        <none>
svc-nginx    10.100.254.138   <nodes>       80:28475/TCP   51s       app=nginx
[root@k8s-master ~/k8s_yaml/Deployment]# curl -I 10.0.0.120:28475
HTTP/1.1 200 OK
Server: nginx/1.13.12
Date: Tue, 13 Jul 2021 07:25:16 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Mon, 09 Apr 2018 16:01:09 GMT
Connection: keep-alive
ETag: "5acb8e45-264"
Accept-Ranges: bytes

shell方式

kubectl autoscale 资源类型资源名称 --max=pod创建数量上限 --min=pod保留数量下限 --cpu-percent=cpu使用百分比 #创建hpa资源
kubectl get horizontalpodautoscaler #查看hpa资源
kubectl get hpa #查看hpa资源

在实际业务场景中，容器CPU使用百分比达到60%左右，建议进行弹性伸缩。

  [root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 autoscale deployment nginx --max=10 --min=2 --cpu-percent=7
  deployment "nginx" autoscaled
  [root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 get horizontalpodautoscaler 
  NAME      REFERENCE          TARGET    CURRENT   MINPODS   MAXPODS   AGE
  nginx     Deployment/nginx   7%        0%        2         10        13s

3. 压测演示

ab -n 总访问次数 -c 单次请求数 http://域名:端口/资源

  [root@k8s-master ~/k8s_yaml/Deployment]# ab -n 1000000 -c 1000 http://10.0.0.120:28475/index.html
  This is ApacheBench, Version 2.3 <$Revision: 1430300 $>
  Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
  Licensed to The Apache Software Foundation, http://www.apache.org/

  Benchmarking 10.0.0.120 (be patient)
  ......

  [root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 get horizontalpodautoscaler 
  NAME      REFERENCE          TARGET    CURRENT   MINPODS   MAXPODS   AGE
  nginx     Deployment/nginx   7%        32%       2         10        14m
  [root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 get deployment nginx
  NAME      DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
  nginx     10        10        10           10          1h
  [root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 get hpa nginx
  NAME      REFERENCE          TARGET    CURRENT   MINPODS   MAXPODS   AGE
  nginx     Deployment/nginx   7%        0%        2         10        18m
  [root@k8s-master ~/k8s_yaml/Deployment]# kubectl -s http://10.0.0.110:10000 get deployment nginx
  NAME      DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
  nginx     2         2         2            2           1h

一、 安装Heapster监控

1. 工作原理

2. 部署服务

二、 部署弹性伸缩

1. 工作原理

2. 创建hpa资源(Shell方式)

3. 压测演示

一、安装Heapster监控

二、部署弹性伸缩