k8s-v1.18安装Metrics-Server

Metrics-Server概念介绍

Metrics-Server是集群核心监控数据的聚合器，在k8s早期版本中，对资源的监控使用的是heapster的资源监控工具。但是从 Kubernetes 1.8 开始，Kubernetes 通过 Metrics API 获取资源使用指标，例如容器 CPU 和内存使用情况。这些度量指标可以由用户直接访问，例如通过使用kubectl top 命令，或者使用集群中的控制器，,因为k8s的api-server将所有的数据持久化到了etcd中，显然k8s本身不能处理这种频率的采集，而且这种监控数据变化快且都是临时数据，因此需要有一个组件单独处理他们.

环境：K8s-v1.18、Docker-18.06.1-ce

一、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@k8s-master manifests]# ps -ef | grep apiserver
root      22008  21989  4 19:33 ?        00:06:37 kube-apiserver --advertise-address=192.168.181.142 --allow-privileged=true --authorization-mode=Node,RBAC --client-ca-file=/etc/kubernetes/pki/ca.crt --enable-admission-plugins=NodeRestriction --enable-bootstrap-token-auth=true  --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key --etcd-servers=https://127.0.0.1:2379 --insecure-port=0 --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key --requestheader-allowed-names=front-proxy-client --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt --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=10.1.0.0/16 --tls-cert-file=/etc/kubernetes/pki/apiserver.crt --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
root      66924  57038  0 21:47 pts/0    00:00:00 grep --color=auto apiserver

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。

vim /etc/kubernetes/manifests/kube-apiserver.yaml
apiVersion: v1
kind: Pod
metadata:
annotations:
kubeadm.kubernetes.io/kube-apiserver.advertise-address.endpoint: 192.168.10.253:6443
creationTimestamp: null
labels:
component: kube-apiserver
tier: control-plane
name: kube-apiserver
namespace: kube-system
spec:
containers:
- command:
- kube-apiserver
- --advertise-address=192.168.10.253
- --allow-privileged=true
- --authorization-mode=Node,RBAC
- --client-ca-file=/etc/kubernetes/pki/ca.crt
- --enable-admission-plugins=NodeRestriction
- --enable-bootstrap-token-auth=true
- --enable-aggregator-routing=true #添加本行
- --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt
- --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
- --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
- --etcd-servers=https://127.0.0.1:2379
- --insecure-port=0
- --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt
- --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key
- --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
- --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt
- --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key
- --requestheader-allowed-names=front-proxy-client
- --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt
- --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=10.1.0.0/16
- --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
- --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
image: registry.aliyuncs.com/google_containers/kube-apiserver:v1.18.0
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 8
httpGet:
host: 192.168.10.253
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:
path: /etc/pki
type: DirectoryOrCreate
name: etc-pki
- hostPath:
path: /etc/kubernetes/pki
type: DirectoryOrCreate
name: k8s-certs
status: {}

二、安装metrics-server(v0.3.6)

1、下载yaml文件

wget https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.6/components.yaml

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: system:aggregated-metrics-reader
labels:
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"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
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: RoleBinding
metadata:
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: apiregistration.k8s.io/v1beta1
kind: APIService
metadata:
name: v1beta1.metrics.k8s.io
spec:
service:
name: metrics-server
namespace: kube-system
group: metrics.k8s.io
version: v1beta1
insecureSkipTLSVerify: true
groupPriorityMinimum: 100
versionPriority: 100
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: metrics-server
namespace: kube-system
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: metrics-server
namespace: kube-system
labels:
k8s-app: metrics-server
spec:
selector:
matchLabels:
k8s-app: metrics-server
template:
metadata:
name: metrics-server
labels:
k8s-app: metrics-server
spec:
serviceAccountName: metrics-server
volumes:
# mount in tmp so we can safely use from-scratch images and/or read-only containers
- name: tmp-dir
emptyDir: {}
containers:
- name: metrics-server
image: registry.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.6 #修改为阿里云的镜像地址
imagePullPolicy: IfNotPresent
args:
- --cert-dir=/tmp
- --secure-port=4443
- /metrics-server #新增
- --kubelet-preferred-address-types=InternalIP #新增
- --kubelet-insecure-tls #新增
ports:
- name: main-port
containerPort: 4443
protocol: TCP
securityContext:
readOnlyRootFilesystem: true
runAsNonRoot: true
runAsUser: 1000
volumeMounts:
- name: tmp-dir
mountPath: /tmp
nodeSelector:
kubernetes.io/os: linux
kubernetes.io/arch: "amd64"
---
apiVersion: v1
kind: Service
metadata:
name: metrics-server
namespace: kube-system
labels:
kubernetes.io/name: "Metrics-server"
kubernetes.io/cluster-service: "true"
spec:
selector:
k8s-app: metrics-server
ports:
- port: 443
protocol: TCP
targetPort: main-port
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: system:metrics-server
rules:
- apiGroups:
- ""
resources:
- pods
- nodes
- nodes/stats
- namespaces
- configmaps
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
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

3、安装

kubectl apply -f components.yaml

4、查看metrics-server服务状态

[root@k8s-master manifests]# kubectl get pod -n kube-system | grep metrics-server
metrics-server-59dd47f7d9-qbsgq      1/1     Running   0          9m32s

5、检查接口是否有异常

[root@k8s-master manifests]# kubectl describe apiservice v1beta1.metrics.k8s.io
Name:         v1beta1.metrics.k8s.io
Namespace:
Labels:       <none>
Annotations:  API Version:  apiregistration.k8s.io/v1
Kind:         APIService
Metadata:
Creation Timestamp:  2021-02-26T07:55:08Z
Resource Version:    1948553
Self Link:           /apis/apiregistration.k8s.io/v1/apiservices/v1beta1.metrics.k8s.io
UID:                 515535ec-3766-4d8a-a6fe-c7b21781ae81
Spec:
Group:                     metrics.k8s.io
Group Priority Minimum:    100
Insecure Skip TLS Verify:  true
Service:
Name:            metrics-server
Namespace:       kube-system
Port:            443
Version:           v1beta1
Version Priority:  100
Status:
Conditions:
Last Transition Time:  2021-02-26T07:55:15Z
Message:               all checks passed
Reason:                Passed
Status:                True
Type:                  Available
Events:                    <none>

6、执行以下命令，检查节点占用性能情况。

[root@k8s-master manifests]# kubectl top nodes
NAME         CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%
k8s-master   261m         6%     1222Mi          15%
k8s-node1    144m         3%     702Mi           9%
k8s-node2    50m          5%     535Mi           31%

[root@k8s-master manifests]# kubectl top pods
NAME                   CPU(cores)   MEMORY(bytes)
liu-nginx              0m           6Mi
nginx                  0m           4Mi
web-694d958794-52mj9   1m           3Mi
web-694d958794-dmpv8   1m           3Mi
web-694d958794-tv6nc   1m           5Mi