选择合适的Kubernetes (K8S) 版本时，‌通常会选择那些标记为“LTS”（‌Long Term Support）‌的版本，‌因为这些版本通常更稳定并提供更长时间的支持。‌Kubernetes 1.21 LTS版本被认为是最稳定的版本之一

Kubernetes 命令

k8s的更新日志
https://github.com/kubernetes/kubernetes/tree/master/CHANGELOG

kubectl命令自动补全
安装bash-completion工具
yum install -y bash-completion
source /usr/share/bash-completion/bash_completion
source <(kubectl completion bash)
以上只是临时起作用，每次登录终端都得起效需要加入到/root/.bashrc文件中
echo "source /usr/share/bash-completion/bash_completion " >> /.bashrc
echo "source <(kubectl completion bash)"  >> /.bashrc
echo "source <(helm completion bash)" >> ~/.bashrc

一 kuberctl
1 查看命名空间中的资源

 kubectl get pods --namespace kube-system

2 查看命名空间的描述

kubectl describe ns kube-system
Name:         kube-system
Labels:       kubernetes.io/metadata.name=kube-system
Annotations:  <none>
Status:       Active

No resource quota.

No LimitRange resource.

3 describe pod 查看pod的相关信息

kubectl describe pods kube-flannel-ds-amd64-zqs6k --namespace kube-system

4 describe node

kubectl describe node  k8s-master1

5 获取dashboard的相关信息

kubectl get pods,svc -n kubernetes-dashboard
##获取网络映射
kubectl get svc -n kubernetes-dashboard

6 获取所有的命名空间

kubectl get pods --all-namespaces

7 直接删除命名空间

kubectl delete namespaces  kubernetes-dashboard

8 删除命名空间中的节点

--force  强制
kubectl delete pods kube-flannel-ds-amd64-x9hg9 -n kube-system --force

9 访问命名空间

curl --insecure https://192.168.56.200:6443/api/v1/kube-system

10.1 查看需要授权证书的节点

[root@k8s-master logs]# kubectl get csr
NAME                                                   AGE   SIGNERNAME                                    REQUESTOR           REQUESTEDDURATION   CONDITION
node-csr-tsic3mMf63p3vsp_7fZDJ_OrdLPNu0I1B8Z82kGzblQ   17h   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   <none>           Approved

10.2 已经授权的证书无法在deny，但可以通过delete来进行删除操作

[root@k8s-master logs]# kubectl get csr
NAME                                                   AGE   SIGNERNAME                                    REQUESTOR           REQUESTEDDURATION   CONDITION
node-csr-tsic3mMf63p3vsp_7fZDJ_OrdLPNu0I1B8Z82kGzblQ   17h   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   <none>              Approved
#已经授权的证书无法在deny，但可以通过delete来进行删除操作
[root@k8s-master logs]# kubectl delete csr  node-csr-tsic3mMf63p3vsp_7fZDJ_OrdLPNu0I1B8Z82kGzblQ   
certificatesigningrequest.certificates.k8s.io "node-csr-tsic3mMf63p3vsp_7fZDJ_OrdLPNu0I1B8Z82kGzblQ" deleted
[root@k8s-master logs]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE                         ERROR
scheduler            Healthy   ok                              
etcd-0               Healthy   {"health":"true","reason":""}   
controller-manager   Healthy   ok                              
[root@k8s-master logs]# kubectl get csr
NAME                                                   AGE   SIGNERNAME                                    REQUESTOR           REQUESTEDDURATION   CONDITION
node-csr-tsic3mMf63p3vsp_7fZDJ_OrdLPNu0I1B8Z82kGzblQ   4s    kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   <none>              Pending

二 Deployment 应用
1 Pod 容器的集合，通常将紧密相关的一组容器放到一个pod中，同一个pod中的所有容器共享IP地址和
Port空间，它们在一个network namespace中

2 k8s部署一个应用
kubectl run 命名 --image=docker.io/kubernetes-bootcamp:v1 --port=8080
默认情况下，所有pod只能在集群内部访问，为了能够从外部访问，需要将容器的8080端口映射到节点的端口
kubectl expose deployment/kubernetes-bootcamp --type=“NodePort” --port 8080

3 k8s获取端口映射
kubectl get services
curl 主机名:映射的端口

4 k8s获取副本数
kubectl get deployments

5 scale
k8s将副本数增加到3个

kubectl scale deployments/kubernetes-bootcamp --replicas=3

[root@k8s-master1 package]# kubectl get deployments
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment   1/3     3            1           2d4h
[root@k8s-master1 package]# kubectl delete  deployments/nginx-deployment
deployment.apps "nginx-deployment" deleted

6 k8s删除一个副本

kubectl scale deployments/kubernetes-bootcamp --replicas=2
kubectl get deployments
kubectl get pods

7 滚动更新

kubectl  set image deployments/kubernetes-bootcamp \ 
kubernetes-bootcamp=jocatalin/kubernetes-bootcamp:v2

8 回退到v1版本

kubectl  rellout undo deployments/kubernetes-bootcamp

验证 curl 主机名:映射的端口

9 获取某一概念的帮助explain

kubectl explain deloyment
kubectl explain 命令用于查看某个 Kubernetes 对象的详细信息，例如对象的定义、字段、类型和其他相关信息。这个命令可以用来了解和掌握 Kubernetes 对象的结构和行为。


1. 如果你想查看某个 Kubernetes 命令的用法，可以使用以下步骤：
使用 kubectl help 命令来查看所有可用命令的列表，找到你想要查看用法的命令。例如，如果你想查看 kubectl expose 命令的用法，可以输入以下命令： 
kubectl help expose
2. 如果你想查看命令的详细用法信息，可以使用 kubectl help <command> --detail 命令。例如，如果你想查看 kubectl expose 命令的详细用法信息，可以输入以下命令： 
kubectl help expose --detail
这将显示一个非常详细的使用说明，包括命令的各种选项和参数。
3. 如果你想查看某个特定参数的用法，可以使用 kubectl help <command> <parameter> 命令。例如，如果你想查看 kubectl expose 命令中的 --type 参数的用法，可以输入以下命令：
kubectl help expose --type
这将显示该参数的用法信息。

10 kubectl edit查看 集群中当前运行的资源

[root@k8s-master1 cfg]# kubectl edit deployment nginx-deployment

#Please edit the object below. Lines beginning with a '#' will be ignored,
#and an empty file will abort the edit. If an error occurs while saving this file will be
#reopened with the relevant failures.
#
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "1"
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"labels":{"app":"nginx"},"name":"nginx-deployment","namespace":"default"},"spec":{"replicas":2,"selector":{"matchLabels":{"app":"nginx"}},"template":{"metadata":{"labels":{"app":"nginx"}},"spec":{"containers":[{"image":"nginx:stable","name":"nginx","ports":[{"containerPort":80}]}]}}}}
  creationTimestamp: "2021-09-06T07:07:49Z"
  generation: 1
  labels:
    app: nginx
  name: nginx-deployment
  namespace: default
  resourceVersion: "117504"
  uid: 7c4a2831-edcb-4db9-85f8-b557ee2debd7
spec:
  progressDeadlineSeconds: 600
  replicas: 2
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: nginx
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx:stable
        imagePullPolicy: IfNotPresent
        name: nginx
        ports:
        - containerPort: 80
          protocol: TCP
        resources: {}

11 销毁

如果只是短时间内不用可以只删除service，如果长时间不用删除deployment和service
[root@kube-master ~]# kubectl delete -f dashboard-service.yaml
service "kubernetes-dashboard" deleted
[root@kube-master ~]# kubectl delete -f dashboard-deployment.yaml
deployment "kubernetes-dashboard-latest" deleted

12 授权

kubectl get clusterrolebinding #查看集群中的clusterrolebingding

kubectl get clusterrolebinding cluster-admin -o yaml  #获取名称为cluster-admin的clusterrolebingding配置信息

13 显示完整信息
-o wide 查看详细信息

[root@k8s-master1 ~]# kubectl get pod,svc --all-namespaces -o wide
NAMESPACE              NAME                                             READY   STATUS    RESTARTS   AGE    IP               NODE          NOMINATED NODE   READINESS GATES
default                pod/busybox                                      1/1     Running   54         169d   10.244.1.172     k8s-node1     <none>           <none>
default                pod/nginx-deployment-5ff58d798d-lxvbn            1/1     Running   17         159d   10.244.0.48      k8s-master1   <none>           <none>
default                pod/nginx-deployment-5ff58d798d-r2k8b            1/1     Running   22         162d   10.244.0.35      k8s-master1   <none>           <none>
default                pod/producer-consumer                            2/2     Running   16         153d   10.244.0.43      k8s-master1   <none>           <none>
kube-system            pod/blackbox-exporter-799f9c6db6-46ckf           1/1     Running   1          70d    10.244.1.173     k8s-node1     <none>           <none>
kube-system            pod/cadvisor-62qdw                               1/1     Running   1          70d    192.168.56.201   k8s-node1     <none>           <none>
kube-system            pod/cadvisor-6b8mp                               1/1     Running   1          70d    192.168.56.200   k8s-master1   <none>           <none>
kube-system            pod/coredns-7fddc7545-4l6pm                      1/1     Running   37         169d   10.244.1.193     k8s-node1     <none>           <none>
kube-system            pod/kube-flannel-ds-98mlk                        1/1     Running   20         168d   192.168.56.200   k8s-master1   <none>           <none>
kube-system            pod/kube-flannel-ds-cdjgn                        1/1     Running   10         166d   192.168.56.201   k8s-node1     <none>           <none>
kube-system            pod/kube-state-metrics-5c896ff656-mtqxl          1/1     Running   4          70d    10.244.0.52      k8s-master1   <none>           <none>
kube-system            pod/node-exporter-2gwkv                          1/1     Running   1          70d    192.168.56.200   k8s-master1   <none>           <none>
kube-system            pod/node-exporter-zf8dq                          1/1     Running   1          70d    192.168.56.201   k8s-node1     <none>           <none>
kubernetes-dashboard   pod/dashboard-metrics-scraper-79c5968bdc-fq4s9   1/1     Running   34         166d   10.244.0.49      k8s-master1   <none>           <none>
kubernetes-dashboard   pod/kubernetes-dashboard-66cfbc8556-s45rx        1/1     Running   18         162d   10.244.1.195     k8s-node1     <none>           <none>

NAMESPACE              NAME                                TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)                  AGE    SELECTOR
default                service/kubernetes                  ClusterIP   10.0.0.1     <none>        443/TCP                  166d   <none>
default                service/nginx-service               NodePort    10.0.0.126   <none>        80:32153/TCP             162d   app=nginx
default                service/web-svc                     NodePort    10.0.0.204   <none>        8080:30392/TCP           154d   run=web
kube-system            service/blackbox-exporter           ClusterIP   10.0.0.151   <none>        9115/TCP                 70d    app=blackbox-exporter
kube-system            service/kube-dns                    ClusterIP   10.0.0.2     <none>        53/UDP,53/TCP,9153/TCP   169d   k8s-app=kube-dns
kubernetes-dashboard   service/dashboard-metrics-scraper   ClusterIP   10.0.0.177   <none>        8000/TCP                 172d   k8s-app=dashboard-metrics-scraper
kubernetes-dashboard   service/kubernetes-dashboard        NodePort    10.0.0.138   <none>        443:30001/TCP            172d   k8s-app=kubernetes-dashboard

14 创建命名空间

kubectl create namespace test-env 

kubectl run nginx --image=nginx --namespace=test-env

15 如何在节点上使用kubectl命令

[root@k8s-master1 ~]# scp -r ~/.kube 192.168.56.201:~/
[root@k8s-master1 ~]# scp /usr/bin/kubectl 192.168.56.201:/usr/bin

16 查看日志

kubectl logs container_name -n namespace

17 导出yaml

导出Pod的配置信息到文件：
kubectl get pod my-pod -n my-namespace -o yaml > pod.yaml

导出Deployment的配置信息到文件：
kubectl get deployment my-deployment -n my-namespace -o yaml > deployment.yaml

导出Service的配置信息到文件：
kubectl get service my-service -n my-namespace -o yaml > service.yaml

18 复制本地文件到pod

kubectl cp <本地路径> <目标Pod名称>:<容器内的目标路径>

19 查看日志

kubectl logs -f calico-node-2w9vh -n kube-system --tail I0

-f 追踪日志
–tail 从后到前，查看日志多少行