解析Kubernetes监控指标获取方式对比

对比

node-exporter用于采集服务器层面的运行指标，包括机器的loadavg、filesystem、meminfo等基础监控，类似于传统主机监控维度的zabbix-agent。 metric-server/heapster是从api-server中获取CPU、内存使用率这种监控指标，并把他们发送给存储后端，如InfluxDB或云厂商，他当前的核心作用是：为HPA等组件提供决策指标支持。 kube-state-metrics关注于获取Kubernetes各种资源的最新状态，如Deployment或者DaemonSet。 例如：

• 我调度了多少个Replicas？现在可用的有几个？

• 多少个Pod是running/stopped/terminated状态？

• Pod重启了多少次？

• 我有多少job在运行中?

这些指标都由kube-state-metrics提供。 之所以没有把kube-state-metrics纳入到metric-server的能力中，是因为他们的关注点本质上是不一样的。

• metric-server仅仅是获取、格式化现有数据，写入特定的存储，实质上是一个监控系统。

• kube-state-metrics是将Kubernetes的运行状况在内存中做了个快照，并且获取新的指标，但他没有能力导出这些指标。
  部署metric-server

下载metric-server部署的yaml文件到本地。

wgethttps://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.7/components.yaml

拉取metric-server的镜像到本地：

#dockerpullzhaoqinchang/metrics-server:0.3.7 0.3.7:Pullingfromzhaoqinchang/metrics-server 9ff2acc3204b:Pullcomplete 9d14b55ff9a0:Pullcomplete Digest:sha256:c0efe772bb9e5c289db6cc4bc2002c268507d0226f2a3815f7213e00261c38e9 Status:Downloadednewerimageforzhaoqinchang/metrics-server:0.3.7 docker.io/zhaoqinchang/metrics-server:0.3.7

修改components.yaml文件为如下内容：

#catcomponents.yaml --- apiVersion:rbac.authorization.k8s.io/v1 kind:ClusterRole metadata: name:system:aggregated-metrics-reader labels: rbac.authorization.k8s.io/aggregate-to-view:"true" rbac.authorization.k8s.io/aggregate-to-edit:"true" rbac.authorization.k8s.io/aggregate-to-admin:"true" rules: -apiGroups:["metrics.k8s.io"] resources:["pods","nodes"] verbs:["get","list","watch"] --- apiVersion:rbac.authorization.k8s.io/v1 kind:ClusterRoleBinding metadata: name:metrics-serverauth-delegator roleRef: apiGroup:rbac.authorization.k8s.io kind:ClusterRole name:system:auth-delegator subjects: -kind:ServiceAccount name:metrics-server namespace:kube-system --- apiVersion:rbac.authorization.k8s.io/v1 kind:RoleBinding metadata: name:metrics-server-auth-reader namespace:kube-system roleRef: apiGroup:rbac.authorization.k8s.io kind:Role name:extension-apiserver-authentication-reader subjects: -kind:ServiceAccount name:metrics-server namespace:kube-system --- apiVersion:apiregistration.k8s.io/v1beta1 kind:APIService metadata: name:v1beta1.metrics.k8s.io spec: service: name:metrics-server namespace:kube-system group:metrics.k8s.io version:v1beta1 insecureSkipTLSVerify:true groupPriorityMinimum:100 versionPriority:100 --- apiVersion:v1 kind:ServiceAccount metadata: name:metrics-server namespace:kube-system --- apiVersion:apps/v1 kind:Deployment metadata: name:metrics-server namespace:kube-system labels: k8s-app:metrics-server spec: selector: matchLabels: k8s-app:metrics-server template: metadata: name:metrics-server labels: k8s-app:metrics-server spec: serviceAccountName:metrics-server volumes: #mountintmpsowecansafelyusefrom-scratchimagesand/orread-onlycontainers -name:tmp-dir emptyDir:{} containers: -name:metrics-server image:zhaoqinchang/metrics-server:0.3.7#修改镜像为刚刚拉取下来的镜像 imagePullPolicy:IfNotPresent args: ---cert-dir=/tmp ---secure-port=4443 command:#添加以下三行command命令 -/metrics-server ---kubelet-preferred-address-types=InternalIP ---kubelet-insecure-tls ports: -name:main-port containerPort:4443 protocol:TCP securityContext: readOnlyRootFilesystem:true runAsNonRoot:true runAsUser:1000 volumeMounts: -name:tmp-dir mountPath:/tmp nodeSelector: kubernetes.io/os:linux --- apiVersion:v1 kind:Service metadata: name:metrics-server namespace:kube-system labels: kubernetes.io/name:"Metrics-server" kubernetes.io/cluster-service:"true" spec: selector: k8s-app:metrics-server ports: -port:443 protocol:TCP targetPort:main-port --- apiVersion:rbac.authorization.k8s.io/v1 kind:ClusterRole metadata: name:system:metrics-server rules: -apiGroups: -"" resources: -pods -nodes -nodes/stats -namespaces -configmaps verbs: -get -list -watch --- apiVersion:rbac.authorization.k8s.io/v1 kind:ClusterRoleBinding metadata: name:system:metrics-server roleRef: apiGroup:rbac.authorization.k8s.io kind:ClusterRole name:system:metrics-server subjects: -kind:ServiceAccount name:metrics-server namespace:kube-system 部署metric-server：

#kubectlapply-fcomponents.yaml clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-readercreated clusterrolebinding.rbac.authorization.k8s.io/metrics-serverauth-delegatorcreated rolebinding.rbac.authorization.k8s.io/metrics-server-auth-readercreated apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.iocreated serviceaccount/metrics-servercreated deployment.apps/metrics-servercreated service/metrics-servercreated clusterrole.rbac.authorization.k8s.io/system:metrics-servercreated clusterrolebinding.rbac.authorization.k8s.io/system:metrics-servercreated

查看metric.k8s.io是否出现在Kubernetes集群的API群组列表中：

#kubectlapi-versions|grepmetrics metrics.k8s.io/v1beta1

使用

kubectl top命令可显示节点和Pod对象的资源使用信息，它依赖于集群中的资源指标API来收集各项指标数据。它包含有Node和Pod两个子命令，可分别显示Node对象和Pod对象的相关资源占用率。 列出Node资源占用率命令的语法格式为“kubectl top node [-l label | NAME]”，例如下面显示所有节点的资源占用状况的结果中显示了各节点累计CPU资源占用时长及百分比，以及内容空间占用量及占用比例。必要时，也可以在命令直接给出要查看的特定节点的标识，以及使用标签选择器进行节点过滤。

[root@mastermetric]#kubectltopnodes NAMECPU(cores)CPU%MEMORY(bytes)MEMORY% master282m14%1902Mi51% node-0270m3%1371Mi37% node-03121m1%892Mi11%

而名称空间级别的Pod对象资源占用率的使用方法会略有不同，使用时，一般应该跟定名称空间及使用标签选择器过滤出目标Pod对象。例如，下面显示kube-system名称空间下的Pod资源使用状况：

[root@mastermetric]#kubectltoppods-nkube-system NAMECPU(cores)MEMORY(bytes) etcd-master32m300Mi kube-apiserver-master86m342Mi kube-controller-manager-master30m48Mi kube-flannel-ds-l5ghn5m10Mi kube-flannel-ds-rqlm24m12Mi kube-flannel-ds-v92r94m14Mi kube-proxy-7vjcv18m15Mi kube-proxy-xrz8f13m21Mi kube-proxy-zpwn61m14Mi kube-scheduler-master7m17Mi metrics-server-5549c7694f-7vb662m14Mi

kubectl top命令为用户提供简洁、快速获取Node对象及Pod对象系统资源占用状况的接口，是集群运行和维护的常用命令之一。 原文链接：https://juejin.cn/post/6996862439560052773

编辑：jq