Kubernetes安装和部署metrics-server

#一、metrics-server简介
自kubernetes 1.8开始，资源使用指标（如容器 CPU 和内存使用率）通过 Metrics API 在 Kubernetes 中获取，metrics-server 替代了heapster。Metrics Server 实现了Resource Metrics API，Metrics Server 是集群范围资源使用数据的聚合器。
Metrics Server 从每个节点上的 Kubelet 公开的 Summary API 中采集指标信息。

Kubernetes中有些组件依赖资源指标API(metric API)的功能 ，如kubectl top 、hpa。如果没有资源指标API接口，这些组件无法运行。在之前使用的是Heapster，Heapster废弃后改用metrics-server。

• 通过Metrics API可以获取指定node或者pod的当前资源使用情况（而无法获取历史数据）
• Metrics API的api路径：/apis/metrics.k8s.io/
• Metrics API的使用需要在K8S集群中成功部署metrics server

kubernetes metrics server 参考文档 https://github.com/kubernetes-incubator/metrics-server

#二、安装metrics-server

1、下载所需文件# mkdir ./metrics-server  # cd metrics-server/  # for file in aggregated-metrics-reader.yaml auth-delegator.yaml auth-reader.yaml metrics-apiservice.yaml metrics-server-deployment.yaml metrics-server-service.yaml resource-reader.yaml; do  wget https://raw.githubusercontent.com/kubernetes-incubator/metrics-server/master/deploy/1.8%2B/$file;done 2、这里需要改2个地方，一个是镜像的问题，一个是服务启动的问题。  # 在所有Node节点上执行。先把镜像国通阿里云的镜像源下载下来。再改个名字。  docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.3  docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.3 k8s.gcr.io/metrics-server-amd64:v0.3.3  # 修改metrics-server-deployment.yaml，增加一个imagePullPolicy，增加command内容，否则会报错no metrics known for node。相关问题原因自行百度。  # vim metrics-server-deployment.yaml   30       containers:   31       - name: metrics-server   32         image: k8s.gcr.io/metrics-server-amd64:v0.3.3   33         imagePullPolicy: IfNotPresent   34         command:   35           - /metrics-server   36           - --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP 37           - --kubelet-insecure-tls   38         volumeMounts:   39         - name: tmp-dir   40           mountPath: /tmp  # kubectl apply -f ./  clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created  clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created  rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created  apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created serviceaccount/metrics-server created  deployment.extensions/metrics-server created  service/metrics-server created  clusterrole.rbac.authorization.k8s.io/system:metrics-server created  clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created  3、查看pod状态  metrics-server-55898485b6-pdhnz               1/1     Running   0          93m    10.244.4.2      huoban-k8s-node01  4、查看node资源使用情况（ 一定要等几分钟，采集数据需要时间） kubectl top node  NAME                  CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%     huoban-k8s-master01   72m          3%     612Mi           16%         huoban-k8s-master02   93m          4%     713Mi           19%         huoban-k8s-master03   108m         5%     674Mi           18%         huoban-k8s-node01     26m          1%     334Mi           9%          huoban-k8s-node02     26m          1%     339Mi           9%        5、查看pod资源使用情况# kubectl top pods -n kube-systemNAME                                          CPU(cores)   MEMORY(bytes)coredns-6967fb4995-4qlfb                      1m           13Micoredns-6967fb4995-frv2p                      1m           12Mietcd-huoban-k8s-master01                      22m          358Mietcd-huoban-k8s-master02                      25m          364Mietcd-huoban-k8s-master03                      23m          381Mikube-apiserver-huoban-k8s-master01            15m          267Mikube-apiserver-huoban-k8s-master02            13m          255Mikube-apiserver-huoban-k8s-master03            17m          249Mikube-controller-manager-huoban-k8s-master01   7m           69Mikube-controller-manager-huoban-k8s-master02   0m           14Mikube-controller-manager-huoban-k8s-master03   0m           14Mikube-flannel-ds-amd64-6bp76                   1m           21Mikube-flannel-ds-amd64-nrvvz                   1m           15Mikube-flannel-ds-amd64-shv4n                   1m           16Mikube-flannel-ds-amd64-t77n4                   1m           15Mikube-proxy-8d522                              1m           19Mikube-proxy-9ng4j                              1m           18Mikube-proxy-htw7p                              1m           20Mikube-proxy-n9r48                              1m           17Mikube-proxy-nsqgh                              1m           17Mikube-scheduler-huoban-k8s-master01            1m           27Mikube-scheduler-huoban-k8s-master02            0m           16Mikube-scheduler-huoban-k8s-master03            0m           13Mikubernetes-dashboard-86844cc55f-sz4gn         0m           13Mimetrics-server-d9d75756b-l75wj                1m           17Mi