kubernetes中kubectl命令管理pod资源

前言

kubectl是运行kubernetes集群命令的管理工具，通过命令行参数转换为对apiserver的REST API调用，并将调用结果输出
kubectl的语法格式

kubectl [命令] [选项]

命令操作

1、查看帮助信息

[root@localhost ~]# 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  --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）
（1）创建一个名称为nginx-deployment的pods，镜像使用nginx，端口为80，创建副本集为3

[root@localhost ~]# kubectl run nginx-deployment --image=nginx --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-deployment created

（2）查看创建的pod资源

[root@localhost ~]# kubectl get pods	//可在末尾加上"-w"可以是查看到创建pod的资源动态
NAME                                READY   STATUS    RESTARTS   AGE
nginx-deployment-5477945587-ntn6r   1/1     Running   0          2m27s
nginx-deployment-5477945587-rfn7d   1/1     Running   0          2m27s
nginx-deployment-5477945587-tj89b   1/1     Running   0          2m27s

（3）pod资源创建同时会创建deployment（控制器）和replicaset（副本集）资源

[root@localhost ~]# kubectl get pods,deployment,replicaset
NAME                                    READY   STATUS    RESTARTS   AGE
pod/nginx-deployment-5477945587-ntn6r   1/1     Running   0          4m18s
pod/nginx-deployment-5477945587-rfn7d   1/1     Running   0          4m18s
pod/nginx-deployment-5477945587-tj89b   1/1     Running   0          4m18s

NAME                                     DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
deployment.extensions/nginx-deployment   3         3         3            3           4m15s

NAME                                                DESIRED   CURRENT   READY   AGE
replicaset.extensions/nginx-deployment-5477945587   3         3         3       4m18s

3、发布（kubectl expose命令），service提供负载均衡功能

[root@localhost ~]# kubectl expose deployment nginx-deployment \
> --port=80 --target-port=80 --name=nginx-service \
> --type=NodePort
service/nginx-service exposed
#查看pod及暴露的端口信息
[root@localhost ~]# kubectl get pods,svc
NAME                                    READY   STATUS    RESTARTS   AGE
pod/nginx-deployment-5477945587-ntn6r   1/1     Running   0          36m
pod/nginx-deployment-5477945587-rfn7d   1/1     Running   0          36m
pod/nginx-deployment-5477945587-tj89b   1/1     Running   0          36m

NAME                    TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
service/kubernetes      ClusterIP   10.0.0.1             443/TCP        10d
service/nginx-service   NodePort    10.0.0.202           80:30916/TCP   42s
#查看网络状态详细信息
[root@localhost ~]# kubectl get pods -o wide
NAME                                READY   STATUS    RESTARTS   AGE   IP            NODE            NOMINATED NODE
nginx-deployment-5477945587-ntn6r   1/1     Running   0          45m   172.17.79.3   192.168.7.102   
nginx-deployment-5477945587-rfn7d   1/1     Running   0          45m   172.17.23.4   192.168.7.103   
nginx-deployment-5477945587-tj89b   1/1     Running   0          45m   172.17.23.3   192.168.7.103   
#查看关联后的节点
[root@localhost ~]# kubectl get endpoints
NAME            ENDPOINTS                                      AGE
kubernetes      192.168.7.100:6443,192.168.7.101:6443          10d
nginx-service   172.17.23.3:80,172.17.23.4:80,172.17.79.3:80   9m38s

• 完成发布后，就可以使用本地浏览器访问创建的pod资源了

#查看pod的访问日志
[root@localhost ~]# kubectl logs nginx-deployment-5477945587-ntn6r
172.17.79.1 - - [10/May/2020:05:44:36 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36" "-"
2020/05/10 05:44:36 [error] 6#6: *1 open() "/usr/share/nginx/html/favicon.ico" failed (2: No such file or directory), client: 172.17.79.1, server: localhost, request: "GET /favicon.ico HTTP/1.1", host: "192.168.7.102:30916", referrer: "http://192.168.7.102:30916/"
172.17.79.1 - - [10/May/2020:05:44:36 +0000] "GET /favicon.ico HTTP/1.1" 404 556 "http://192.168.7.102:30916/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36" "-"
[root@localhost ~]# kubectl logs nginx-deployment-5477945587-rfn7d
172.17.23.1 - - [10/May/2020:05:45:21 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36" "-"
2020/05/10 05:45:21 [error] 6#6: *1 open() "/usr/share/nginx/html/favicon.ico" failed (2: No such file or directory), client: 172.17.23.1, server: localhost, request: "GET /favicon.ico HTTP/1.1", host: "192.168.7.103:30916", referrer: "http://192.168.7.103:30916/"
172.17.23.1 - - [10/May/2020:05:45:21 +0000] "GET /favicon.ico HTTP/1.1" 404 556 "http://192.168.7.103:30916/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36" "-"

4、更新（kubectl set命令）

• 创建完成的pod中可以看到nginx的版本为1.17版本

• 将此版本更改为1.14版本

[root@localhost ~]# kubectl set image deployment/nginx-deployment nginx-deployment=nginx:1.14
deployment.extensions/nginx-deployment image updated

5、回滚（kubectl rollout命令）

#查看版本历史
[root@localhost ~]# kubectl rollout history deployment/nginx-deployment
deployment.extensions/nginx-deployment 
REVISION  CHANGE-CAUSE
1         
2         
#执行回滚
[root@localhost ~]# kubectl rollout undo deployment/nginx-deployment
deployment.extensions/nginx-deployment

• 再次使用浏览器访问即可查看到版本的信息变更为1.17版本

6、删除（kubectl delete命令）

[root@localhost ~]# kubectl delete deploy/nginx-deployment
deployment.extensions "nginx-deployment" deleted
[root@localhost ~]# kubectl get pods
No resources found.
#此时虽然删除了pod资源，但是发布pod资源的时候创建的nginx-service资源还在
[root@localhost ~]# kubectl get svc
NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.0.0.1             443/TCP        10d
nginx-service   NodePort    10.0.0.202           80:30916/TCP   38m
#删除nginx-service
[root@localhost ~]# kubectl delete svc/nginx-service
service "nginx-service" deleted
[root@localhost ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.0.0.1             443/TCP   10d