Kubernetes 部署 Metrics Server 获取集群指标数据
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前言
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[1]
1. 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。
2. 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
## ServiceAccount
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
k8s-app: metrics-server
name: metrics-server
namespace: kube-system
---
## ClusterRole aggregated-metrics-reader
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: system:aggregated-metrics-reader
labels:
k8s-app: metrics-server
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"]
---
## ClusterRole metrics-server
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: system:metrics-server
labels:
k8s-app: metrics-server
rules:
- apiGroups: [""]
resources: ["pods","nodes","nodes/stats","namespaces","configmaps"]
verbs: ["get","list","watch"]
---
## ClusterRoleBinding auth-delegator
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: metrics-server:system:auth-delegator
labels:
k8s-app: metrics-server
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: system:auth-delegator
subjects:
- kind: ServiceAccount
name: metrics-server
namespace: kube-system
---
## RoleBinding metrics-server-auth-reader
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: metrics-server-auth-reader
namespace: kube-system
labels:
k8s-app: metrics-server
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: extension-apiserver-authentication-reader
subjects:
- kind: ServiceAccount
name: metrics-server
namespace: kube-system
---
## ClusterRoleBinding system:metrics-server
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: system:metrics-server
labels:
k8s-app: metrics-server
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: system:metrics-server
subjects:
- kind: ServiceAccount
name: metrics-server
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
$ kubectl apply -f metrics-rbac.yaml -n kube-system
3. 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
## APIService
apiVersion: apiregistration.k8s.io/v1
kind: APIService
metadata:
labels:
k8s-app: metrics-server
name: v1beta1.metrics.k8s.io
spec:
group: metrics.k8s.io
service:
name: metrics-server
namespace: kube-system
version: v1beta1
groupPriorityMinimum: 100
insecureSkipTLSVerify: true
versionPriority: 100
通过 Kubectl 工具部署 Metrics APIService
$ kubectl apply -f metrics-api-service.yaml -n kube-system
4. 部署 Metrics Server 应用
创建 Metrics 部署文件
metrics-server-deploy.yaml
## Service
apiVersion: v1
kind: Service
metadata:
labels:
k8s-app: metrics-server
name: metrics-server
namespace: kube-system
spec:
ports:
- name: https
port: 443
protocol: TCP
targetPort: https
selector:
k8s-app: metrics-server
---
## Deployment
apiVersion: apps/v1
kind: Deployment
metadata:
name: metrics-server
namespace: kube-system
labels:
k8s-app: metrics-server
spec:
selector:
matchLabels:
k8s-app: metrics-server
strategy:
rollingUpdate:
maxUnavailable: 0
template:
metadata:
name: metrics-server
labels:
k8s-app: metrics-server
spec:
hostNetwork: true
serviceAccountName: metrics-server
containers:
- name: metrics-server
image: bitnami/metrics-server:0.4.1
imagePullPolicy: IfNotPresent
args:
- --cert-dir=/tmp
- --secure-port=4443
- --kubelet-insecure-tls
- --kubelet-use-node-status-port
- --kubelet-preferred-address-types=InternalDNS,InternalIP,ExternalDNS,ExternalIP,Hostname
livenessProbe:
failureThreshold: 3
httpGet:
path: /livez
port: https
scheme: HTTPS
periodSeconds: 10
readinessProbe:
failureThreshold: 3
httpGet:
path: /readyz
port: https
scheme: HTTPS
periodSeconds: 10
ports:
- name: https
containerPort: 4443
protocol: TCP
securityContext:
readOnlyRootFilesystem: true
runAsNonRoot: true
runAsUser: 1000
resources:
limits:
memory: 1Gi
cpu: 1000m
requests:
memory: 1Gi
cpu: 1000m
volumeMounts:
- name: tmp-dir
mountPath: /tmp
- name: localtime
readOnly: true
mountPath: /etc/localtime
volumes:
- name: tmp-dir
emptyDir: {}
- name: localtime
hostPath:
type: File
path: /etc/localtime
nodeSelector:
kubernetes.io/os: linux
通过 Kubectl 工具部署 Metrics 应用
$ kubectl apply -f metrics-server-deploy.yaml -n kube-system
5. 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：
## 获取全部节点指标信息
$ kubectl top node
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
k8s-master 228m 5% 1204Mi 44%
k8s-node-2-12 131m 1% 1843Mi 23%
k8s-node-2-13 73m 0% 576Mi 7%
## 获取某个 Namespace Pod 的指标信息
$ kubectl top pods -n kube-system
NAME CPU(cores) MEMORY(bytes)
coredns-9d85f5447-c82w7 7m 22Mi
coredns-9d85f5447-kcmb4 7m 21Mi
dashboard-metrics-scraper-65f454dff8-2pts8 1m 22Mi
etcd-k8s-master 22m 104Mi
kube-apiserver-k8s-master 58m 311Mi
kube-controller-manager-k8s-master 27m 46Mi
## 获取某个 Namespace 下某个 Pod 的指标信息
$ kubectl top pods coredns-9d85f5447-c82w7 -n kube-system
NAME CPU(cores) MEMORY(bytes)
coredns-9d85f5447-c82w7 7m 21Mi
## 获取全部 Namespace 下的 Pod 的指标信息
$ kubectl top pods --all-namespaces
NAMESPACE NAME CPU(cores) MEMORY(bytes)
kube-system coredns-9d85f5447-c82w7 6m 22Mi
kube-system coredns-9d85f5447-kcmb4 6m 21Mi
kube-system dashboard-metrics-scraper-65f454dff8-2pts8 1m 22Mi
kube-system etcd-k8s-master 21m 106Mi
kube-system kube-apiserver-k8s-master 62m 311Mi
kube-system kube-controller-manager-k8s-master 26m 46Mi
kube-system kube-proxy-kpt7c 2m 36Mi
kube-system kube-proxy-zb2l5 1m 27Mi
kube-system kube-scheduler-k8s-master 5m 21Mi
kube-system kubernetes-dashboard-7bf47cd79c-nctx2 1m 55Mi
kube-system metrics-server-6d54447849-nnbfk 3m 20Mi
参考资料
[1]
Kubernetes 部署 Metrics Server 部署文件: https://github.com/my-dlq/blog-example/tree/master/kubernetes/kubernetes-metrics-server
原文链接：http://www.mydlq.club/article/77/
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