在Kubernetes集群上安装Metrics Server

落日映苍穹つ 2022-11-21 11:34 202阅读 0赞

### 文章目录 ###

*  在Kubernetes集群上安装Metrics Server
 *   *  前言
     *  参考文档
     *  安装前检查网络
     *  安装Metrics Server
     *  参考文档

# 在Kubernetes集群上安装Metrics Server #

## 前言 ##

Kubernetes集群使用Metrics Server来采集容器的CPU和内存使用情况，用来监控Node和Pod的CPU和内存使用情况，并用作HPA（自动横向扩展）。

本文描述了如何在Kubernetes集群上安装Metrics Server。

*  CentOS7 x86\_84
 *  kubeadm方式安装Kubernetes集群
 *  Kubernetes v1.19.3
 *  Metrics Server v0.3.7

## 参考文档 ##

*  [https://github.com/kubernetes-sigs/metrics-server][https_github.com_kubernetes-sigs_metrics-server]
 *  [https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.7/components.yaml][https_github.com_kubernetes-sigs_metrics-server_releases_download_v0.3.7_components.yaml]

## 安装前检查网络 ##

Metrics Server依赖于Kubernetes网络插件来保持Metrics Server与kubelet的通信。

以Calico为例，需要先检查Calico的安装情况。

# Check daemonset 
    kubectl get ds -n kube-system -l k8s-app=calico-node
    
    # Check pod status and ready
    kubectl get pods -n kube-system -l k8s-app=calico-node
    
    # Check apiservice status
    kubectl get apiservice v1.crd.projectcalico.org -o yaml

## 安装Metrics Server ##

下载Metrics Server的Manifest文件：

*  [https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.7/components.yaml][https_github.com_kubernetes-sigs_metrics-server_releases_download_v0.3.7_components.yaml]

修改components.yaml:

*  将Deployment的`.spec.template.spec.containers.image`修改为可以正常拉取的`metrics-server:v0.3.7`镜像。
 *  在Deployment的`.spec.template.spec.containers.args`下添加：
    
        - --kubelet-insecure-tls
        - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname

说明：

*  `--kubelet-insecure-tls`: skip verifying Kubelet CA certificates.
 *  `--kubelet-preferred-address-types`: Order to consider Kubelet node address types when connecting to Kubelet.

一个完整的例子参见：

*  [metrics-server-insecure.yaml][]

安装Metrics Server:

kubectl apply -f components.yaml

验证Metrics Server:

# Check deployment
    kubectl get deployment metrics-server -n kube-system
    
    # Check pod status and ready
    kubectl get pods -n kube-system -l k8s-app=metrics-server
    
    # Check apiservice status
    kubectl get apiservice v1beta1.metrics.k8s.io -o yaml

等待几分钟后，验证是否可以从Metrics Server查询到资源使用情况：

kubectl top nodes
    kubectl top pods -A

> 如果出现“error: metrics not available yet”，则等待几分钟后再尝试。如果一直报错，需要先检查网络组件是否正常工作，再检查Metrics Server的日志。

如果仍然启动Metrics Server失败，考虑使用`hostNetWork`方式，参见：

*  [metrics-server-insecure-hostnetwork.yaml][]

> The reason we had to use “hostNetwork: true” was because the ip of the node was included in the CIDR of the pod network.

## 参考文档 ##

*  [https://github.com/kubernetes-sigs/metrics-server/issues/300][https_github.com_kubernetes-sigs_metrics-server_issues_300]
 *  [https://github.com/kubernetes-sigs/metrics-server/issues/278][https_github.com_kubernetes-sigs_metrics-server_issues_278]
 *  [https://computingforgeeks.com/how-to-deploy-metrics-server-to-kubernetes-cluster/][https_computingforgeeks.com_how-to-deploy-metrics-server-to-kubernetes-cluster]
 *  [https://github.com/kubernetes-sigs/metrics-server/blob/master/FAQ.md][https_github.com_kubernetes-sigs_metrics-server_blob_master_FAQ.md]

[https_github.com_kubernetes-sigs_metrics-server]: https://github.com/kubernetes-sigs/metrics-server
[https_github.com_kubernetes-sigs_metrics-server_releases_download_v0.3.7_components.yaml]: https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.7/components.yaml
[metrics-server-insecure.yaml]: https://github.com/cookcodeblog/k8s-deploy/blob/master/kubeadm_v1.19.3/metrics-server/metrics-server-insecure.yaml
[metrics-server-insecure-hostnetwork.yaml]: https://github.com/cookcodeblog/k8s-deploy/blob/master/kubeadm_v1.19.3/metrics-server/metrics-server-insecure-hostnetwork.yaml
[https_github.com_kubernetes-sigs_metrics-server_issues_300]: https://github.com/kubernetes-sigs/metrics-server/issues/300
[https_github.com_kubernetes-sigs_metrics-server_issues_278]: https://github.com/kubernetes-sigs/metrics-server/issues/278
[https_computingforgeeks.com_how-to-deploy-metrics-server-to-kubernetes-cluster]: https://computingforgeeks.com/how-to-deploy-metrics-server-to-kubernetes-cluster/
[https_github.com_kubernetes-sigs_metrics-server_blob_master_FAQ.md]: https://github.com/kubernetes-sigs/metrics-server/blob/master/FAQ.md