Kubernetes 部署 Metrics Server 获取集群指标数据

2020-11-18 11:22:00 kubernetes metrics metrics server

文章目录

系统环境：

Kubernetes 版本：1.19.4
Metrics Server 版本：v4.0.1

示例部署文件地址：

Kubernetes 部署 Metrics Server 部署文件

一、Metrics Server 简介

介绍 Metrics Server 前首先介绍下 Heapster，该工具是用于 Kubernetes 集群监控和性能分析工具，可以收集节点上的指标数据，例如，节点的 CPU、Memory、Network 和 Disk 的 Metric 数据。不过在 Kubernetes V1.11 版本后将被逐渐废弃。而 Metrics Server 正是 Heapster 的代替者。

Metrics Server 是 Kubernetes 集群核心监控数据的聚合器，可以通过 Metrics API 的形式获取 Metrics 数据，不过仅仅是获取指标的最新值，不对旧值进行存储，且不负责将指标转发到第三方目标。Metrics Server 还可以与 Kubectl 工具结合使用，提供 kubectl top 命令来展示集群中的指标数据，接下来我们开始部署 Metrics Server。

二、部署应用权限 RBAC 资源

Kubernetes 部署 Metrics Server 前需要先提前部署 RBAC 相关配置，这样 Metrics Server 才能有足够的权限获取系统组件的信息。

创建 Metrics RBAC 文件

metrics-rbac.yaml

 1## ServiceAccount
 2apiVersion: v1
 3kind: ServiceAccount
 4metadata:
 5  labels:
 6    k8s-app: metrics-server
 7  name: metrics-server
 8  namespace: kube-system
 9---
10## ClusterRole aggregated-metrics-reader
11apiVersion: rbac.authorization.k8s.io/v1
12kind: ClusterRole
13metadata:
14  name: system:aggregated-metrics-reader
15  labels:
16    k8s-app: metrics-server
17    rbac.authorization.k8s.io/aggregate-to-view: "true"
18    rbac.authorization.k8s.io/aggregate-to-edit: "true"
19    rbac.authorization.k8s.io/aggregate-to-admin: "true"
20rules:
21- apiGroups: ["metrics.k8s.io"]
22  resources: ["pods","nodes"]
23  verbs: ["get","list","watch"]
24---
25## ClusterRole metrics-server
26apiVersion: rbac.authorization.k8s.io/v1
27kind: ClusterRole
28metadata:
29  name: system:metrics-server
30  labels:
31    k8s-app: metrics-server
32rules:
33- apiGroups: [""]
34  resources: ["pods","nodes","nodes/stats","namespaces","configmaps"]
35  verbs: ["get","list","watch"]
36---
37## ClusterRoleBinding auth-delegator
38apiVersion: rbac.authorization.k8s.io/v1
39kind: ClusterRoleBinding
40metadata:
41  name: metrics-server:system:auth-delegator
42  labels:
43    k8s-app: metrics-server
44roleRef:
45  apiGroup: rbac.authorization.k8s.io
46  kind: ClusterRole
47  name: system:auth-delegator
48subjects:
49- kind: ServiceAccount
50  name: metrics-server
51  namespace: kube-system
52---
53## RoleBinding metrics-server-auth-reader
54apiVersion: rbac.authorization.k8s.io/v1
55kind: RoleBinding
56metadata:
57  name: metrics-server-auth-reader
58  namespace: kube-system
59  labels:
60    k8s-app: metrics-server
61roleRef:
62  apiGroup: rbac.authorization.k8s.io
63  kind: Role
64  name: extension-apiserver-authentication-reader
65subjects:
66- kind: ServiceAccount
67  name: metrics-server
68  namespace: kube-system
69---
70## ClusterRoleBinding system:metrics-server
71apiVersion: rbac.authorization.k8s.io/v1
72kind: ClusterRoleBinding
73metadata:
74  name: system:metrics-server
75  labels:
76    k8s-app: metrics-server
77roleRef:
78  apiGroup: rbac.authorization.k8s.io
79  kind: ClusterRole
80  name: system:metrics-server
81subjects:
82- kind: ServiceAccount
83  name: metrics-server
84  namespace: kube-system

通过 Kubectl 工具部署 Metrics RBAC

-n：指定部署应用的 Namespace 命名空间

1$ kubectl apply -f metrics-rbac.yaml -n kube-system

三、部署 APIService 资源

设置扩展 API Service 工作于聚合层，允许使用其 API 扩展 Kubernetes apiserver，而这些 API 并不是核心 Kubernetes API 的一部分。这里部署 APIservice 资源，来提供 Kubernetes Metrics 指标 API 数据。

创建 Metrics APIService 文件

metrics-api-service.yaml

 1## APIService
 2apiVersion: apiregistration.k8s.io/v1
 3kind: APIService
 4metadata:
 5  labels:
 6    k8s-app: metrics-server
 7  name: v1beta1.metrics.k8s.io
 8spec:
 9  group: metrics.k8s.io
10  service:
11    name: metrics-server
12    namespace: kube-system
13  version: v1beta1
14  groupPriorityMinimum: 100
15  insecureSkipTLSVerify: true
16  versionPriority: 100

通过 Kubectl 工具部署 Metrics APIService

-n：指定部署应用的 Namespace 命名空间

1$ kubectl apply -f metrics-api-service.yaml -n kube-system

四、部署 Metrics Server 应用

创建 Metrics 部署文件

metrics-server-deploy.yaml

 1## Service
 2apiVersion: v1
 3kind: Service
 4metadata:
 5  labels:
 6    k8s-app: metrics-server
 7  name: metrics-server
 8  namespace: kube-system
 9spec:
10  ports:
11  - name: https
12    port: 443
13    protocol: TCP
14    targetPort: https
15  selector:
16    k8s-app: metrics-server
17---
18## Deployment
19apiVersion: apps/v1
20kind: Deployment
21metadata:
22  name: metrics-server
23  namespace: kube-system
24  labels:
25    k8s-app: metrics-server
26spec:
27  selector:
28    matchLabels:
29      k8s-app: metrics-server
30  strategy:
31    rollingUpdate:
32      maxUnavailable: 0
33  template:
34    metadata:
35      name: metrics-server
36      labels:
37        k8s-app: metrics-server
38    spec:
39      hostNetwork: true
40      serviceAccountName: metrics-server
41      containers:
42      - name: metrics-server
43        image: bitnami/metrics-server:0.4.1
44        imagePullPolicy: IfNotPresent
45        args:
46          - --cert-dir=/tmp
47          - --secure-port=4443
48          - --kubelet-insecure-tls
49          - --kubelet-use-node-status-port
50          - --kubelet-preferred-address-types=InternalDNS,InternalIP,ExternalDNS,ExternalIP,Hostname
51        livenessProbe:
52          failureThreshold: 3
53          httpGet:
54            path: /livez
55            port: https
56            scheme: HTTPS
57          periodSeconds: 10
58        readinessProbe:
59          failureThreshold: 3
60          httpGet:
61            path: /readyz
62            port: https
63            scheme: HTTPS
64          periodSeconds: 10
65        ports:
66        - name: https
67          containerPort: 4443
68          protocol: TCP
69        securityContext:
70          readOnlyRootFilesystem: true
71          runAsNonRoot: true
72          runAsUser: 1000
73        resources:
74          limits:
75            memory: 1Gi
76            cpu: 1000m
77          requests:
78            memory: 1Gi
79            cpu: 1000m
80        volumeMounts:
81        - name: tmp-dir
82          mountPath: /tmp
83        - name: localtime
84          readOnly: true
85          mountPath: /etc/localtime
86      volumes:
87      - name: tmp-dir
88        emptyDir: {}
89      - name: localtime
90        hostPath:
91          type: File
92          path: /etc/localtime
93      nodeSelector:
94        kubernetes.io/os: linux

通过 Kubectl 工具部署 Metrics 应用

-n：指定部署应用的 Namespace 命名空间

1$ kubectl apply -f metrics-server-deploy.yaml -n kube-system

五、进行测试

当部署完 Metrics Server 后，可以通过 kubectl 工具进行测试，默认支持下面命令：

kubectl top pod： 获取 Pod 的 CPU、Memory 使用信息。
kubectl top node： 获取 Node 的 CPU、Memory 使用信息。

输入上面命令进行测试，如下：

 1## 获取全部节点指标信息
 2$ kubectl top node
 3NAME            CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%   
 4k8s-master      228m         5%     1204Mi          44%       
 5k8s-node-2-12   131m         1%     1843Mi          23%       
 6k8s-node-2-13   73m          0%     576Mi           7%     
 7
 8## 获取某个 Namespace Pod 的指标信息
 9$ kubectl top pods -n kube-system
10NAME                                         CPU(cores)   MEMORY(bytes)   
11coredns-9d85f5447-c82w7                      7m           22Mi            
12coredns-9d85f5447-kcmb4                      7m           21Mi            
13dashboard-metrics-scraper-65f454dff8-2pts8   1m           22Mi            
14etcd-k8s-master                              22m          104Mi           
15kube-apiserver-k8s-master                    58m          311Mi           
16kube-controller-manager-k8s-master           27m          46Mi
17
18## 获取某个 Namespace 下某个 Pod 的指标信息
19$ kubectl top pods coredns-9d85f5447-c82w7 -n kube-system
20NAME                      CPU(cores)   MEMORY(bytes)
21coredns-9d85f5447-c82w7   7m           21Mi  
22
23## 获取全部 Namespace 下的 Pod 的指标信息
24$ kubectl top pods --all-namespaces
25NAMESPACE     NAME                                           CPU(cores)   MEMORY(bytes)
26kube-system   coredns-9d85f5447-c82w7                        6m           22Mi            
27kube-system   coredns-9d85f5447-kcmb4                        6m           21Mi            
28kube-system   dashboard-metrics-scraper-65f454dff8-2pts8     1m           22Mi            
29kube-system   etcd-k8s-master                                21m          106Mi           
30kube-system   kube-apiserver-k8s-master                      62m          311Mi           
31kube-system   kube-controller-manager-k8s-master             26m          46Mi            
32kube-system   kube-proxy-kpt7c                               2m           36Mi            
33kube-system   kube-proxy-zb2l5                               1m           27Mi            
34kube-system   kube-scheduler-k8s-master                      5m           21Mi            
35kube-system   kubernetes-dashboard-7bf47cd79c-nctx2          1m           55Mi            
36kube-system   metrics-server-6d54447849-nnbfk                3m           20Mi

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