1、概述
Metrics Server 是一种可扩展、高效的容器资源指标来源,适用于 Kubernetes 内置的自动缩放管道。
Metrics Server 从 Kubelets 收集资源指标,并通过Metrics API将它们暴露在 Kubernetes apiserver 中,供 Horizontal Pod Autoscaler和Vertical Pod Autoscaler使用。指标 API 也可以通过 访问kubectl top,从而更容易调试自动缩放管道。
2、metrics-server安装要求
Metrics Server 对集群和网络配置有特定的要求。这些要求并不是所有集群分布的默认要求。在使用 Metrics Server 之前,请确保您的集群分布支持这些要求:
- kube-apiserver 必须启用聚合层。
- 节点必须启用 Webhook身份验证和授权。
- Kubelet 证书需要由集群证书颁发机构签名(或通过传递–kubelet-insecure-tls给 Metrics Server 来禁用证书验证)注意这里是重点,如果本地没有签名需要传递args : “–kubelet-insecure-tls” 给Metrics Server
- 容器运行时必须实现容器指标 RPC(或具有cAdvisor支持)
- 网络应支持以下通信:
- 控制平面到指标服务器。控制平面节点需要到达 Metrics Server 的 pod IP 和端口 10250(或节点 IP 和自定义端口,如果hostNetwork已启用)
- 所有节点上的 Kubelet 的指标服务器。指标服务器需要到达节点地址和 Kubelet 端口。地址和端口在 Kubelet 中配置并作为 Node 对象的一部分发布。字段中的地址.status.addresses和端口.status.daemonEndpoints.kubeletEndpoint.port(默认 10250)。Metrics Server 将根据kubelet-preferred-address-types命令行标志(InternalIP,ExternalIP,Hostname清单中的默认值)提供的列表选择第一个节点地址
3、版本对照
Metrics Server | Metrics API group/version | 支持k8s版本 |
---|---|---|
0.6.x | metrics.k8s.io/v1beta1 | 1.19+ |
0.5.x | metrics.k8s.io/v1beta1 | *1.8+ |
0.4.x | metrics.k8s.io/v1beta1 | *1.8+ |
0.3.x | metrics.k8s.io/v1beta1 | 1.8-1.21 |
4、kubernetes1.25安装metrics-server0.6.2
由于我们本地是kubernetes1.25版本的,按照metrics-server 要求,需要安装metrics-server0.6版本
4.1、下载metrics-server0.6.2 yaml 并修改
下载地址:https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.6.2/components.yaml
主要 改两个地方
- 134行添加参数 “–kubelet-insecure-tls” 用以禁用证书验证
- 140行更改镜像地址为阿里云:“registry.cn-hangzhou.aliyuncs.com/chenby/metrics-server:v0.6.2”
更改后yaml
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
k8s-app: metrics-server
name: metrics-server
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
k8s-app: metrics-server
rbac.authorization.k8s.io/aggregate-to-admin: "true"
rbac.authorization.k8s.io/aggregate-to-edit: "true"
rbac.authorization.k8s.io/aggregate-to-view: "true"
name: system:aggregated-metrics-reader
rules:
- apiGroups:
- metrics.k8s.io
resources:
- pods
- nodes
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
k8s-app: metrics-server
name: system:metrics-server
rules:
- apiGroups:
- ""
resources:
- nodes/metrics
verbs:
- get
- apiGroups:
- ""
resources:
- pods
- nodes
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
labels:
k8s-app: metrics-server
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: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
k8s-app: metrics-server
name: metrics-server:system:auth-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: ClusterRoleBinding
metadata:
labels:
k8s-app: metrics-server
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
---
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
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
k8s-app: metrics-server
name: metrics-server
namespace: kube-system
spec:
selector:
matchLabels:
k8s-app: metrics-server
strategy:
rollingUpdate:
maxUnavailable: 0
template:
metadata:
labels:
k8s-app: metrics-server
spec:
containers:
- args:
- --kubelet-insecure-tls
- --cert-dir=/tmp
- --secure-port=4443
- --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
- --kubelet-use-node-status-port
- --metric-resolution=15s
image: registry.cn-hangzhou.aliyuncs.com/chenby/metrics-server:v0.6.2
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 3
httpGet:
path: /livez
port: https
scheme: HTTPS
periodSeconds: 10
name: metrics-server
ports:
- containerPort: 4443
name: https
protocol: TCP
readinessProbe:
failureThreshold: 3
httpGet:
path: /readyz
port: https
scheme: HTTPS
initialDelaySeconds: 20
periodSeconds: 10
resources:
requests:
cpu: 100m
memory: 200Mi
securityContext:
allowPrivilegeEscalation: false
readOnlyRootFilesystem: true
runAsNonRoot: true
runAsUser: 1000
volumeMounts:
- mountPath: /tmp
name: tmp-dir
nodeSelector:
kubernetes.io/os: linux
priorityClassName: system-cluster-critical
serviceAccountName: metrics-server
volumes:
- emptyDir: {}
name: tmp-dir
---
apiVersion: apiregistration.k8s.io/v1
kind: APIService
metadata:
labels:
k8s-app: metrics-server
name: v1beta1.metrics.k8s.io
spec:
group: metrics.k8s.io
groupPriorityMinimum: 100
insecureSkipTLSVerify: true
service:
name: metrics-server
namespace: kube-system
version: v1beta1
versionPriority: 100
4.2、执行并验证
# 执行yaml
[root@k8s-master ~]# kubectl apply -f components.yaml
serviceaccount/metrics-server created
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created
clusterrole.rbac.authorization.k8s.io/system:metrics-server created
rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created
clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created
clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created
service/metrics-server created
deployment.apps/metrics-server created
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created
# 验证 metrics-server 使用的命名空间为 kube-system 一下pod中 metrics-server-f68c598fc-vt4pz 为 metrics-server 已正常启动
[root@k8s-master ~]# kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
calico-kube-controllers-59697b644f-bqhsg 1/1 Running 0 10d
calico-node-6x9rq 1/1 Running 0 10d
calico-node-9npwl 1/1 Running 0 10d
calico-node-s9g7k 1/1 Running 0 10d
coredns-c676cc86f-n4nj8 1/1 Running 0 10d
coredns-c676cc86f-rhvwg 1/1 Running 0 10d
etcd-k8s-master 1/1 Running 0 10d
kube-apiserver-k8s-master 1/1 Running 0 10d
kube-controller-manager-k8s-master 1/1 Running 0 10d
kube-proxy-62sbc 1/1 Running 0 10d
kube-proxy-qq58v 1/1 Running 0 10d
kube-proxy-w6p29 1/1 Running 0 10d
kube-scheduler-k8s-master 1/1 Running 0 10d
metrics-server-f68c598fc-vt4pz 1/1 Running 0 61s
[root@k8s-master ~]#
[root@k8s-master ~]#
# 查看每个节点资源使用情况
[root@k8s-master ~]# kubectl top nodes
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
k8s-master 410m 5% 2845Mi 18%
k8s-node1 98m 2% 4511Mi 59%
k8s-node2 990m 12% 21520Mi 33%
[root@k8s-master ~]#
[root@k8s-master ~]#
# 查看pod 资源使用情况
[root@k8s-master ~]# kubectl top pods metrics-server-f68c598fc-vt4pz -n kube-system
NAME CPU(cores) MEMORY(bytes)
metrics-server-f68c598fc-vt4pz 3m 16Mi
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