k8s安装metrics-server
Kubernetes Metrics Server：
Kubernetes Metrics Server 是 Cluster 的核⼼监控数据的聚合器，kubeadm 默认是不部署的。
Metrics Server 供 Dashboard 等其他组件使⽤，是⼀个扩展的 APIServer，依赖于 API Aggregator。所以，在安装 Metrics Server 之前需要先在 kube-apiserver 中开启 API
Aggregator。
Metrics API 只可以查询当前的度量数据，并不保存历史数据。
Metrics API URI 为 /apis/metrics.k8s.io/，在 k8s.io/metrics 下维护。
必须部署 metrics-server 才能使⽤该 API，metrics-server 通过调⽤ kubelet Summary API 获取数据。
⼀、前提条件
注意：使⽤ Metrics Server 有必备两个条件：
1、API Server 启⽤ Aggregator Routing ⽀持。否则 API Server 不识别请求：
Error from server (ServiceUnavailable): the server is currently unable to handle the request (ics.k8s.io)
2、API Server 能访问 Metrics Server Pod IP。否则 API Server ⽆法访问 Metrics Server：
E1223 07:23:04.330206      1 :420] ics.k8s.io failed with: failing or missing response from 10.171.248.214:4443/apis/metrics.k8s.io/v1beta1: Get 10.171.248.214:4443/apis/metrics.k8s.io/v1beta1 3、启⽤API Aggregator，API Aggregation 允许在不修改 Kubernetes 核⼼代码的同时扩展 Kubernetes API，即：将第三⽅服务注册到 Kubernetes API 中，这样就可以通过
Kubernetes API 来访问第三⽅服务了，例如：Metrics Server API。注：另外⼀种扩展 Kubernetes API 的⽅法是使⽤ CRD（Custom Resource Definition，⾃定义资源定义）。
⼆、修改配置
1、检查 API Server 是否开启了 Aggregator Routing：查看 API Server 是否具有 --enable-aggregator-routing=true 选项。
[root@master1 ~]# ps -ef | grep apiserver
root      12721  10738  0 20:46 pts/0    00:00:00 grep --color=auto apiserver
root    111575 111557  6 16:42 ?        00:16:51 kube-apiserver --advertise-address=192.168.200.3 --allow-privileged=true --authorization-mode=Node,RBAC --client-ca-file=/etc/kubernetes/ --enable-admission-plugins=NodeRestriction --en 2、修改每个 API Server 的 kube-apiserver.yaml 配置开启 Aggregator Routing：修改 manifests 配置后 API Server 会⾃动重启⽣效。
cat /etc/kubernetes/manifests/kube-apiserver.yaml
apiVersion: v1
kind: Pod
metadata:
annotations:
kubeadm.kubernetes.io/dpoint: 192.168.200.3:6443
creationTimestamp: null
labels:
component: kube-apiserver
tier: control-plane
name: kube-apiserver
namespace: kube-system
spec:
containers:
- command:
- kube-apiserver
- --advertise-address=192.168.200.3
- --allow-privileged=true
-
--authorization-mode=Node,RBAC
- --client-ca-file=/etc/kubernetes/
- --enable-admission-plugins=NodeRestriction
- --enable-bootstrap-token-auth=true
- --enable-aggregator-routing=true            # 添加本⾏
- --etcd-cafile=/etc/kubernetes/pki/
- --etcd-certfile=/etc/kubernetes/
- --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
- --etcd-servers=127.0.0.1:2379
- --insecure-port=0
- --kubelet-client-certificate=/etc/kubernetes/
-
--kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key
- --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
- --proxy-client-cert-file=/etc/kubernetes/
- --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key
- --requestheader-allowed-names=front-proxy-client
- --requestheader-client-ca-file=/etc/kubernetes/
- --requestheader-extra-headers-prefix=X-Remote-Extra-
- --requestheader-group-headers=X-Remote-Group
- --requestheader-username-headers=X-Remote-User
- --secure-port=6443
- --service-account-key-file=/etc/kubernetes/pki/sa.pub
-
--service-cluster-ip-range=10.96.0.0/12
- --tls-cert-file=/etc/kubernetes/
- --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
image: io/kube-apiserver:v1.18.2
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 8
httpGet:
host: 192.168.200.3
path: /healthz
port: 6443
scheme: HTTPS
initialDelaySeconds: 15
timeoutSeconds: 15
name: kube-apiserver
resources:
requests:
cpu: 250m
volumeMounts:
- mountPath: /etc/ssl/certs
name: ca-certs
readOnly: true
-
mountPath: /etc/pki
name: etc-pki
readOnly: true
- mountPath: /etc/kubernetes/pki
name: k8s-certs
readOnly: true
hostNetwork: true
priorityClassName: system-cluster-critical
volumes:
- hostPath:
path: /etc/ssl/certs
type: DirectoryOrCreate
name: ca-certs
- hostPath:
type: DirectoryOrCreate
name: etc-pki
- hostPath:
path: /etc/kubernetes/pki
type: DirectoryOrCreate
name: k8s-certs
status: {}
github地址：
github/kubernetes-sigs/metrics-server/releases
三、安装
1、下载yaml⽂件
wget github/kubernetes-sigs/metrics-server/releases/download/v0.4.1/components.yaml 2、修改components.yaml⽂件
cat components.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:
- pods
-
nodes
- nodes/stats
- namespaces
- configmaps
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
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:
- --cert-dir=/tmp
- --secure-port=4443
- --kubelet-preferred-address-types=InternalIP  # 删掉 ExternalIP,Hostname这两个，这⾥已经改好了，你那边要⾃⼰核对⼀下        - --kubelet-use-node-status-port
- --kubelet-insecure-tls                    #  加上该启动参数
image: io/metrics-server/metrics-server:v0.4.1                # 镜像地址根据情况修改
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 3
httpGet:
path: /livez
port: https
scheme: HTTPS
nodeselectorperiodSeconds: 10
name: metrics-server
ports:
- containerPort: 4443
name: https
protocol: TCP
readinessProbe:
failureThreshold: 3
httpGet:
path: /readyz
port: https
scheme: HTTPS
periodSeconds: 10
securityContext:
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: ics.k8s.io
spec:
group: metrics.k8s.io
groupPriorityMinimum: 100
insecureSkipTLSVerify: true
service:
name: metrics-server
namespace: kube-system
version: v1beta1
versionPriority: 100
3、安装
kubectl apply -f components.yaml
4、查看metrics-server服务状态
[root@master1 ~]# kubectl get pod -n kube-system | grep metrics-server
metrics-server-6f9f86ddf9-zphlw  1/1    Running  0          11s
5、检查 API Server 是否可以连通 Metrics Server
[root@master1 ~]# kubectl describe svc metrics-server -n kube-system
Name:              metrics-server
Namespace:        kube-system
Labels:            kubernetes.io/cluster-service=true
kubernetes.io/name=Metrics-server
Annotations:      Selector:  k8s-app=metrics-server
Type:              ClusterIP
IP:                10.107.86.150
Port:              <unset>  443/TCP
TargetPort:        main-port/TCP
Endpoints:        10.244.2.20:4443
Session Affinity:  None
Events:            <none>
# 在其他⼏个节点ping⼀下Endpoints的地址
[root@master3 ~]# ping 10.244.2.20
PING 10.244.2.20 (10.244.2.20) 56(84) bytes of data.
64 bytes from 10.244.2.20: icmp_seq=1 ttl=64 time=0.122 ms
64 bytes from 10.244.2.20: icmp_seq=2 ttl=64 time=0.032 ms
6、执⾏以下命令，检查节点占⽤性能情况。
[root@master1 ~]# kubectl top nodes
NAME      CPU(cores)  CPU%  MEMORY(bytes)  MEMORY%  master1  223m        5%    1433Mi          52%
master2  148m        3%    972Mi          35%
master3  183m        4%    1123Mi          41%
node1    225m        5%    1389Mi          50%
[root@master1 ~]# kubectl top pods
NAME                                      CPU(cores)  MEMORY(bytes)  details-v1-6fc55d65c9-l97cs              4m          36Mi
nfs-client-provisioner-6d4469b5b5-ndg5x  4m          20Mi            productpage-v1-9cf6c76b5-hc2nr            10m          71Mi            ratings-v1-6f855c5fff-v9ht2              3m          28Mi            reviews-v1-697f45b7dd-w9fgc              7m          117Mi          reviews-v2-8c85b467b-jgx6w                6m          113Mi          reviews-v3-76ccf79776-74vz6              5m          117Mi

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