Docker & K8S

Kubernetes其他知识和应用技巧

其他知识和应用技巧

使用kubectl top命令

k8s使用top命令报错如下

[root@master ~]# kubectl top pods
error: Metrics API not available

说明没有安装metrics-server插件
安装步骤如下：

#下载yaml文件
wget https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml -O metrics-server-components.yaml
#更改yaml文件里面的阿里云地址
sed -i 's/k8s.gcr.io\/metrics-server/registry.cn-hangzhou.aliyuncs.com\/google_containers/g' metrics-server-components.yaml
#执行部署metrics-server
kubectl apply -f metrics-server-components.yaml

metrics-server-components.yaml文件内容：

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:
        - --cert-dir=/tmp
        - --secure-port=4443
        - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
        - --kubelet-use-node-status-port
        - --metric-resolution=15s
        - --kubelet-insecure-tls
        image: registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server:v0.6.3
        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

如果有如下报错：
x509: cannot validate certificate for 10.10.10.6 because it doesn't contain any IP SANs
需要修改配置忽略CA验证

vim metrics-server-components.yaml
-----------------------------------------
 spec:
      containers:
      - args:
        - --cert-dir=/tmp
        - --secure-port=4443
        - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
        - --kubelet-use-node-status-port
        - --metric-resolution=15s
        - --kubelet-insecure-tls                   
###新增--kubelet-insecure-tls 就不会去验证Kubelets提供的服务证书的CA

等服务启动之后就可以使用top命令了

[root@master ~]# kubectl get pods -n kube-system |grep metrics-server
metrics-server-55db4f88bc-s9pkz   1/1     Running   0          9m43s
[root@master ~]# kubectl top nodes
NAME     CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%
master   239m         11%    895Mi           33%
node1    86m          4%     406Mi           15%
node2    97m          4%     446Mi           16%

K8S证书更新

查看所有证书的有效期时间：

[root@master ~]# kubeadm certs check-expiration
[check-expiration] Reading configuration from the cluster...
[check-expiration] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'

CERTIFICATE                EXPIRES                  RESIDUAL TIME   CERTIFICATE AUTHORITY   EXTERNALLY MANAGED
admin.conf                 Apr 22, 2025 08:00 UTC   364d            ca                      no      
apiserver                  Apr 22, 2025 08:00 UTC   364d            ca                      no      
apiserver-etcd-client      Apr 22, 2025 08:00 UTC   364d            etcd-ca                 no      
apiserver-kubelet-client   Apr 22, 2025 08:00 UTC   364d            ca                      no      
controller-manager.conf    Apr 22, 2025 08:00 UTC   364d            ca                      no      
etcd-healthcheck-client    Apr 22, 2025 08:00 UTC   364d            etcd-ca                 no      
etcd-peer                  Apr 22, 2025 08:00 UTC   364d            etcd-ca                 no      
etcd-server                Apr 22, 2025 08:00 UTC   364d            etcd-ca                 no      
front-proxy-client         Apr 22, 2025 08:00 UTC   364d            front-proxy-ca          no      
scheduler.conf             Apr 22, 2025 08:00 UTC   364d            ca                      no      

CERTIFICATE AUTHORITY   EXPIRES                  RESIDUAL TIME   EXTERNALLY MANAGED
ca                      Dec 22, 2033 10:37 UTC   9y              no      
etcd-ca                 Dec 22, 2033 10:37 UTC   9y              no      
front-proxy-ca          Dec 22, 2033 10:37 UTC   9y              no

更新k8s所有证书：

kubeadm certs renew all

注意：更新完了之后需要重启服务才会成功更新证书，否则服务内部证书还是会过期

默认每个证书会更新1年的有效期，如果需要更新更长需要修改kubeadm的代码修改默认证书有效期重新编译安装kubeadm

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kubernetes

Kubernetes其他知识和应用技巧

https://www.ihavecats.cn/archives/kubernetesqi-ta-zhi-shi-he-ying-yong-ji-qiao

作者

一行HelloWorld走天下

发布于

2024-12-21

更新于

2025-09-11

许可协议

CC BY 4.0

Kubernetes其他知识和应用技巧

Kubernetes其他知识和应用技巧

其他知识和应用技巧

使用kubectl top命令

K8S证书更新

作者

发布于

更新于

许可协议

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