详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes

时间:2021-11-20 00:07:40

1、浅析监控方案


heapster是一个监控计算、存储、网络等集群资源的工具,以k8s内置的cAdvisor作为数据源收集集群信息,并汇总出有价值的性能数据(Metrics):cpu、内存、network、filesystem等,然后将这些数据输出到外部存储(backend),如InfluxDB,最后再通过相应的UI界面进行可视化展示,如grafana。 另外heapster的数据源和外部存储都是可插拔的,所以可以很灵活的组建出很多监控方案,如:Heapster+ElasticSearch+Kibana等等。
Heapster的整体架构图:
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes

2、部署


本篇我们将实践 Heapster + InfluxDB + Grafana 的监控方案。使用官方提供的yml文件有一些小问题,请参考以下改动和说明:

2.1、创建InfluxDB资源对象

apiVersion: apps/v1
kind: Deployment
metadata:
  name: monitoring-influxdb
  namespace: kube-system
spec:
  replicas: 1
  selector:
    matchLabels:
      task: monitoring
      k8s-app: influxdb
  template:
    metadata:
      labels:
        task: monitoring
        k8s-app: influxdb
    spec:
      containers:
      - name: influxdb
        image: k8s.gcr.io/heapster-influxdb-amd64:v1.3.3
        volumeMounts:
        - mountPath: /data
 name: influxdb-storage
 volumes:
 - name: influxdb-storage
 emptyDir: {}
---
apiVersion: v1
kind: Service
metadata:
 labels:
 task: monitoring
 kubernetes.io/cluster-service: 'true'
    kubernetes.io/name: monitoring-influxdb
  name: monitoring-influxdb
  namespace: kube-system
spec:
  type: NodePort
  ports:
  - nodePort: 31001
    port: 8086
    targetPort: 8086
  selector:
    k8s-app: influxdb

注意:这里我们使用NotePort暴露monitoring-influxdb服务在主机的31001端口上,那么InfluxDB服务端的地址:http://[host-ip]:31001 ,记下这个地址,以便创建heapster和为grafana配置数据源时,可以直接使用。

2.1、创建Grafana资源对象

apiVersion: apps/v1
kind: Deployment
metadata:
  name: monitoring-grafana
  namespace: kube-system
spec:
  replicas: 1
  selector:
    matchLabels:
      task: monitoring
      k8s-app: grafana
  template:
    metadata:
      labels:
        task: monitoring
        k8s-app: grafana
    spec:
      containers:
      - name: grafana
        image: k8s.gcr.io/heapster-grafana-amd64:v4.4.3
        ports:
        - containerPort: 3000
          protocol: TCP
        volumeMounts:
        - mountPath: /etc/ssl/certs
 name: ca-certificates
 readOnly: true
 - mountPath: /var
          name: grafana-storage
        env:
        - name: INFLUXDB_HOST
          value: monitoring-influxdb
        - name: GF_SERVER_HTTP_PORT
          value: "3000"
          # 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 expose 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
          # If you're only using the API Server proxy, set this value instead:
          # value: /api/v1/namespaces/kube-system/services/monitoring-grafana/proxy
          value: /
      volumes:
      - name: ca-certificates
        hostPath:
          path: /etc/ssl/certs
 - name: grafana-storage
 emptyDir: {}
---
apiVersion: v1
kind: Service
metadata:
 labels:
 # For use as a Cluster add-on (https://github.com/kubernetes/kubernetes/tree/master/cluster/addons)
 # If you are NOT using this as an addon, you should comment out this line.
 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
  # You could also use NodePort to expose the service at a randomly-generated port
  type: NodePort
  ports:
  - nodePort: 30108
    port: 80
    targetPort: 3000
  selector:
    k8s-app: grafana

虽然Heapster已经预先配置好了GrafanaDatasourceDashboard,但是为了方便访问,这里我们使用NotePort暴露monitoring-grafana服务在主机的30108上,那么Grafana服务端的地址:http://registry.wuling.com:30108 ,通过浏览器访问,为Grafana修改数据源,如下:
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
标红的地方,为上一步记录下的InfluxDB服务端的地址。

2.2、创建Heapster资源对象

apiVersion: v1
kind: ServiceAccount
metadata:
  name: heapster
  namespace: kube-system
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: heapster
  namespace: kube-system
spec:
  replicas: 1
  selector:
    matchLabels:
      task: monitoring
      k8s-app: heapster
  template:
    metadata:
      labels:
        task: monitoring
        k8s-app: heapster
    spec:
      serviceAccountName: heapster
      containers:
      - name: heapster
        image: k8s.gcr.io/heapster-amd64:v1.4.2
        imagePullPolicy: IfNotPresent
        command:
        - /heapster
 - --source=kubernetes:https://kubernetes.default 
 - --sink=influxdb:http://150.109.39.33:31001 # 这里填写刚刚记录下的InfluxDB服务端的地址。
---
apiVersion: v1
kind: Service
metadata:
 labels:
 task: monitoring
 # For use as a Cluster add-on (https://github.com/kubernetes/kubernetes/tree/master/cluster/addons)
 # If you are NOT using this as an addon, you should comment out this line.
 kubernetes.io/cluster-service: 'true'
    kubernetes.io/name: Heapster
  name: heapster
  namespace: kube-system
spec:
  ports:
  - port: 80
    targetPort: 8082
  selector:
    k8s-app: heapster

--source 为heapster指定获取集群信息的数据源。参考:https://github.com/kubernetes/heapster/blob/master/docs/source-configuration.md
--sink 为heaster指定后端存储,这里我们使用InfluxDB,其他的,请参考:https://github.com/kubernetes/heapster/blob/master/docs/sink-owners.md
这里heapster留下了一个的坑,请继续往下看,当我部署完heapster,查看Heapster容器组的标准输出:
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
很多人都以为是https或者k8s配置的问题,于是去就慌忙的去配置InSecure http方式,导致坑越来越深,透明度越来越低,更是无从下手,我也是这样弄了很久,都较上劲了,此处省略一万字。。。,当这些路子都走遍了,再次品读下面的原文:
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
才发现是权限的问题,heaster默认使用一个令牌(Token)与ApiServer进行认证,通过查看heapster.yml发现 serviceAccountName: heapster ,现在明白了吧,就是heaster没有权限,那么如何授权呢-----给heaster绑定一个有权限的角色就行了,如下:

apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: heapster
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: heapster
  namespace: kube-system

当创建heapster资源的时候,直接把这段代码加上,就行了。

3、从不同维度查看应用程序性能指标


在k8s集群,应用程序的性能指标,需要从不同的维度(containers, pods, services, and whole clusters)进行统计。以便于使用户深入了解他们的应用程序是如何执行的以及可能出现的应用程序瓶颈。

3.1、通过dashboard查看集群概况

详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
整个监控方案部署成功后,从上图可以看到,在不同粒度/维度下,dashboard上可以呈现对象的具体CPU和内存使用率。

3.2、通过Grafana查看集群详情(cpu、memory、filesystem、network)

通过Grafana可以查看某个Node或Pod的所有资源使用率,包括集群节点、不同NameSpace下的单个Pod等,一部分截图如下所示:
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
详解k8s原生的集群监控方案(Heapster+InfluxDB+Grafana) - kubernetes
从上面可以看到,Heapster 定义的Grafana Dashboard很直观和简单。我们也可以学习 Grafana 来自定制出更美观和满足特定业务需求的Dashboard

4、总结


本篇我们详解了k8s一个完整的监控方案,除了Heapster,还有prometheus(一套开源的监控&报警&时间序列数据库的组合),后面有时间也会进行实战。监控是一个非常大的话题,监控的目的是为预警,预警的目的是为了指导系统自愈。只有把 监控=》预警 =》自愈 三个环节都完成了,以实现对应用程序性能管理和故障管理,才算得上是一个真正意义的监控生态系统(APM),所以这个系列会一直朝着这个目标努力下去,请大家继续关注。如果有什么好的想法,欢迎评论区交流。

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