Kubectl是管理k8s集群的命令行工具，通过生成的json格式传递给apiserver进行创建、查看、管理的操作。

1、帮助信息

[root@master1 ~]# kubectl --help
kubectl controls the Kubernetes cluster manager. 

Find more information at: https://kubernetes.io/docs/reference/kubectl/overview/

Basic Commands (Beginner):
  create         Create a resource from a file or from stdin.
  expose         使用 replication controller, service, deployment 或者 pod 并暴露它作为一个 新的
Kubernetes Service
  run            在集群中运行一个指定的镜像
  set            为 objects 设置一个指定的特征

Basic Commands (Intermediate):
  explain        查看资源的文档
  get            显示一个或更多 resources
  edit           在服务器上编辑一个资源
  delete         Delete resources by filenames, stdin, resources and names, or by resources and label selector

Deploy Commands:
  rollout        Manage the rollout of a resource
  scale          为 Deployment, ReplicaSet, Replication Controller 或者 Job 设置一个新的副本数量
  autoscale      自动调整一个 Deployment, ReplicaSet, 或者 ReplicationController 的副本数量

Cluster Management Commands:
  certificate    修改 certificate 资源.
  cluster-info   显示集群信息
  top            Display Resource (CPU/Memory/Storage) usage.
  cordon         标记 node 为 unschedulable
  uncordon       标记 node 为 schedulable
  drain          Drain node in preparation for maintenance
  taint          更新一个或者多个 node 上的 taints

Troubleshooting and Debugging Commands:
  describe       显示一个指定 resource 或者 group 的 resources 详情
  logs           输出容器在 pod 中的日志
  attach         Attach 到一个运行中的 container
  exec           在一个 container 中执行一个命令
  port-forward   Forward one or more local ports to a pod
  proxy          运行一个 proxy 到 Kubernetes API server
  cp             复制 files 和 directories 到 containers 和从容器中复制 files 和 directories.
  auth           Inspect authorization

Advanced Commands:
  apply          通过文件名或标准输入流(stdin)对资源进行配置
  patch          使用 strategic merge patch 更新一个资源的 field(s)
  replace        通过 filename 或者 stdin替换一个资源
  wait           Experimental: Wait for a specific condition on one or many resources.
  convert        在不同的 API versions 转换配置文件

Settings Commands:
  label          更新在这个资源上的 labels
  annotate       更新一个资源的注解
  completion     Output shell completion code for the specified shell (bash or zsh)

Other Commands:
  alpha          Commands for features in alpha
  api-resources  Print the supported API resources on the server
  api-versions   Print the supported API versions on the server, in the form of "group/version"
  config         修改 kubeconfig 文件
  plugin         Provides utilities for interacting with plugins.
  version        输出 client 和 server 的版本信息

Usage:
  kubectl [flags] [options]

Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).

#项目的生命周期，创建-----> 发布------> 更新------> 回滚------> 删除

2、创建 kubectl run 命令

kubectl run NAME --image=image [--env="key=value"] [--port=port] [--replicas=replicas]
[--dry-run=bool] [--overrides=inline-json] [--command] -- [COMMAND] [args...] [options]

示例：

[root@master1 ~]# kubectl get pod         #检查存在的资源
NAME                    READY   STATUS    RESTARTS   AGE
nginx-dbddb74b8-fskqq   1/1     Running   1          21h

[root@master1 ~]# kubectl delete pod nginx-dbddb74b8-fskqq    #删除存在的pod
pod "nginx-dbddb74b8-fskqq" deleted

[root@master1 ~]# kubectl get pod        #发现删除过后又自动创建了新的pod
NAME                    READY   STATUS    RESTARTS   AGE
nginx-dbdd b74b8-zrlwc   1/1     Running   0          99s

[root@master1 ~]# kubectl get all
NAME                        READY   STATUS    RESTARTS   AGE
pod/nginx-dbddb74b8-zrlwc   1/1     Running   0          6m35s

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.0.0.1     <none>        443/TCP   47h

NAME                    DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/nginx   1         1         1            1           22h

NAME                              DESIRED   CURRENT   READY   AGE
replicaset.apps/nginx-dbddb74b8   1         1         1       22h

[root@master1 ~]# kubectl delete deployment/nginx       #删除nginx控制器
deployment.extensions "nginx" deleted
[root@master1 ~]# kubectl get pod      #此时资源就销毁了
No resources found.
[root@master1 ~]# kubectl get all
NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.0.0.1     <none>        443/TCP   2d

--------开始创建新的资源-------
[root@master1 ~]# kubectl run nginx --image=nginx:latest --port=80 --replicas=3
#创建名为nginx的资源，镜像为nginx最新版，使用replicas=3：3副本机制

[root@master1 ~]# kubectl get pods      #查看资源是否创建成功
NAME                     READY   STATUS    RESTARTS   AGE
nginx-7697996758-gmgpn   1/1     Running   0          95s
nginx-7697996758-jbq5f   1/1     Running   0          95s
nginx-7697996758-sk7xd   1/1     Running   0          95s

[root@master1 ~]# kubectl get pods -o wide      #查看3个资源的ip地址
NAME                     READY   STATUS    RESTARTS   AGE     IP            NODE             NOMINATED NODE
nginx-7697996758-gmgpn   1/1     Running   0          2m11s   172.17.86.3   192.168.200.60   <none>
nginx-7697996758-jbq5f   1/1     Running   0          2m11s   172.17.63.2   192.168.200.40   <none>
nginx-7697996758-sk7xd   1/1     Running   0          2m11s   172.17.86.4   192.168.200.60   <none>


[root@master1 ~]# kubectl get all
NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-7697996758-gmgpn   1/1     Running   0          5m34s
pod/nginx-7697996758-jbq5f   1/1     Running   0          5m34s
pod/nginx-7697996758-sk7xd   1/1     Running   0          5m34s

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.0.0.1     <none>        443/TCP   2d

NAME                    DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/nginx   3         3         3            3           5m34s

NAME                               DESIRED   CURRENT   READY   AGE
replicaset.apps/nginx-7697996758   3         3         3       5m34s

[root@master1 ~]# kubectl get pods,deployment,replicaset
NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-7697996758-gmgpn   1/1     Running   0          33m
pod/nginx-7697996758-jbq5f   1/1     Running   0          33m
pod/nginx-7697996758-sk7xd   1/1     Running   0          33m

NAME                          DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
deployment.extensions/nginx   3         3         3            3           33m

NAME                                     DESIRED   CURRENT   READY   AGE
replicaset.extensions/nginx-7697996758   3         3         3       33m

3、发布nginx service提供负载均衡的功能

格式：
kubectl expose (-f FILENAME | TYPE NAME) [--port=port] [--protocol=TCP|UDP|SCTP]
[--target-port=number-or-name] [--name=name] [--external-ip=external-ip-of-service] [--type=type]
[options]

[root@master1 ~]# kubectl get svc      #先查看已经存在的资源
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.0.0.1     <none>        443/TCP   2d

#发布nginx service
[root@master1 ~]# kubectl expose deployment nginx --port=80 --target-port=80 --name=nginx-service --type=NodePort

4、查看资源对象简写

[root@master1 ~]#  kubectl api-resources

5、查看关联后端的节点

[root@master1 ~]#  kubectl get endpoints
NAME            ENDPOINTS                                      AGE
kubernetes      192.168.200.10:6443,192.168.200.20:6443        2d2h
nginx-service   172.17.63.2:80,172.17.86.3:80,172.17.86.4:80   20m

6、网络状态详细信息

[root@master1 ~]#  kubectl get pods -o wide
NAME                     READY   STATUS    RESTARTS   AGE    IP            NODE             NOMINATED NODE
nginx-7697996758-gmgpn   1/1     Running   0          118m   172.17.86.3   192.168.200.60   <none>
nginx-7697996758-jbq5f   1/1     Running   0          118m   172.17.63.2   192.168.200.40   <none>
nginx-7697996758-sk7xd   1/1     Running   0          118m   172.17.86.4   192.168.200.60   <none>

7、服务暴露的端口

[root@master1 ~]# kubectl get svc
NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.0.0.1     <none>        443/TCP        2d2h
nginx-service   NodePort    10.0.0.242   <none>        80:35988/TCP   22m

此时就可以在外部访问pod资源了

8、在两台node节点安装ipvs

注意：kubernetes里kube-proxy支持三种模式，在v1.8之前我们使用的是iptables 以及 userspace两种模式，在kubernetes 1.8之后引入了ipvs模式

yum install ipvsadm -y


[root@node1 ~]#  ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn  
TCP  172.17.63.1:30001 rr
  -> 172.17.86.2:8443             Masq    1      0          0         
TCP  172.17.63.1:35988 rr
  -> 172.17.63.2:80               Masq    1      0          0         
  -> 172.17.86.3:80               Masq    1      0          0         
  -> 172.17.86.4:80               Masq    1      0          0         
TCP  192.168.122.1:30001 rr
  -> 172.17.86.2:8443             Masq    1      0          0         
TCP  192.168.122.1:35988 rr
  -> 172.17.63.2:80               Masq    1      0          0         
  -> 172.17.86.3:80               Masq    1      0          0         
  -> 172.17.86.4:80               Masq    1      0          0         

9、在node02操作 同样安装ipvsadmin工具查看

10、在master01操作 查看访问日志（注意：如果访问其他node无法访问检查proxy组件）

[root@master1 ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
nginx-7697996758-gmgpn   1/1     Running   0          124m
nginx-7697996758-jbq5f   1/1     Running   0          124m
nginx-7697996758-sk7xd   1/1     Running   0          124m

[root@master1 ~]# kubectl logs nginx-7697996758-gmgpn
[root@master1 ~]# kubectl logs nginx-7697996758-jbq5f
[root@master1 ~]# kubectl logs nginx-7697996758-sk7xd

11、更新nginx 为1.14版本

谷歌浏览器重新加载刷新页面查看nginx版本信息

[root@master1 ~]# kubectl set --help
Configure application resources 

These commands help you make changes to existing application resources.

Available Commands:
  env            Update environment variables on a pod template
  image          更新一个 pod template 的镜像
  resources      在对象的 pod templates 上更新资源的 requests/limits
  selector       设置 resource 的 selector
  serviceaccount Update ServiceAccount of a resource
  subject        Update User, Group or ServiceAccount in a RoleBinding/ClusterRoleBinding

Usage:
  kubectl set SUBCOMMAND [options]

Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).

12、获取修改模板

[root@master1 ~]# kubectl set image deployment/nginx nginx=nginx:1.14

#处于动态监听状态
[root@master1 ~]#  kubectl get pods -w
NAME                     READY   STATUS              RESTARTS   AGE
nginx-6ff7c89c7c-cskmk   1/1     Running             0          52s
nginx-6ff7c89c7c-t5pt7   0/1     ContainerCreating   0          2s
nginx-6ff7c89c7c-vmkcn   1/1     Running             0          26s
nginx-7697996758-gmgpn   1/1     Running             0          140m
nginx-7697996758-jbq5f   0/1     Terminating         0  
//Ctrl+c中断监听，更新速度快


[root@master1 ~]#  kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
nginx-6ff7c89c7c-cskmk   1/1     Running   0          98s
nginx-6ff7c89c7c-t5pt7   1/1     Running   0          48s
nginx-6ff7c89c7c-vmkcn   1/1     Running   0          72s

版本更新成功

13、回滚nginx

[root@master1 ~]# kubectl rollout --help
Manage the rollout of a resource.
  
Valid resource types include: 

  * deployments  
  * daemonsets  
  * statefulsets

Examples:
  # Rollback to the previous deployment
  kubectl rollout undo deployment/abc
  
  # Check the rollout status of a daemonset
  kubectl rollout status daemonset/foo

Available Commands:
  history     显示 rollout 历史
  pause       标记提供的 resource 为中止状态
  resume      继续一个停止的 resource
  status      显示 rollout 的状态
  undo        撤销上一次的 rollout

Usage:
  kubectl rollout SUBCOMMAND [options]

Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).

14、查看历史版本

[root@master1 ~]#  kubectl rollout history deployment/nginx deployment.extensions/nginx 
REVISION  CHANGE-CAUSE
1         <none>
2         <none>

15、执行回滚

[root@master1 ~]#  kubectl rollout undo deployment/nginx

16、检查回滚状态

[root@master1 ~]#  kubectl rollout status deployment/nginx

回滚成功

17、查看deployment

[root@master1 ~]# kubectl get deploy
NAME    DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
nginx   3         3         3            3           147m

18、删除nginx

[root@master1 ~]# kubectl delete deployment/nginx

[root@master1 ~]# kubectl get deploy
No resources found.
[root@master1 ~]# kubectl get pods
No resources found.

19、删除服务SVC

[root@master1 ~]#  kubectl get svc
NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.0.0.1     <none>        443/TCP        2d2h
nginx-service   NodePort    10.0.0.242   <none>        80:35988/TCP   52m

[root@master1 ~]#  kubectl delete svc/nginx-service
service "nginx-service" deleted

[root@master1 ~]#  kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.0.0.1     <none>        443/TCP   2d2h

20、查看具体资源的详细信息

[root@master1 ~]#  kubectl run nginx --image=nginx:latest --port=80 --replicas=3
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
deployment.apps/nginx created


[root@master1 ~]# kubectl get pods
NAME                     READY   STATUS              RESTARTS   AGE
nginx-7697996758-2pvdr   1/1     Running             0          24s
nginx-7697996758-php62   0/1     ContainerCreating   0          24s
nginx-7697996758-pk7gs   0/1     ContainerCreating   0          24s
[root@master1 ~]# kubectl describe pod nginx-7697996758-2pvdr
Name:               nginx-7697996758-2pvdr
Namespace:          default
Priority:           0
PriorityClassName:  <none>
Node:               192.168.200.60/192.168.200.60
Start Time:         Thu, 15 Apr 2021 19:58:05 +0800
Labels:             pod-template-hash=7697996758
                    run=nginx
Annotations:        <none>
Status:             Running
IP:                 172.17.86.3
Controlled By:      ReplicaSet/nginx-7697996758
Containers:
  nginx:
    Container ID:   docker://3c530259a879188cb78e0e458a59296772c5564542e6b75a423ebdf84b0f4cac
    Image:          nginx:latest
    Image ID:       docker-pullable://nginx@sha256:75a55d33ecc73c2a242450a9f1cc858499d468f077ea942867e662c247b5e412
    Port:           80/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Thu, 15 Apr 2021 19:58:21 +0800
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-697gb (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  default-token-697gb:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-697gb
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason     Age   From                     Message
  ----    ------     ----  ----                     -------
  Normal  Pulling    51s   kubelet, 192.168.200.60  pulling image "nginx:latest"
  Normal  Scheduled  50s   default-scheduler        Successfully assigned default/nginx-7697996758-2pvdr to 192.168.200.60
  Normal  Pulled     35s   kubelet, 192.168.200.60  Successfully pulled image "nginx:latest"
  Normal  Created    35s   kubelet, 192.168.200.60  Created container
  Normal  Started    35s   kubelet, 192.168.200.60  Started container

21、查看deployment资源

[root@master1 ~]#  kubectl describe deployment/nginx
Name:                   nginx
Namespace:              default
CreationTimestamp:      Thu, 15 Apr 2021 19:58:06 +0800
Labels:                 run=nginx
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               run=nginx
Replicas:               3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  run=nginx
  Containers:
   nginx:
    Image:        nginx:latest
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   nginx-7697996758 (3/3 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  106s  deployment-controller  Scaled up replica set nginx-7697996758 to 3

22、进入pod

[root@master1 ~]# kubectl exec -it nginx-7697996758-2pvdr bash
root@nginx-7697996758-2pvdr:/#