k8s，盘他！kubectl常规命令操作集锦

前言

一：kubectl管理

• kubectl是管理k8s的命令行工具，通过生成json格式传递给apiserver进行一些操作

• 更全的kubectl命令请查看kubectl --help，以下仅列出常用的命令

  [root@master ~]# 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).
  
  

1.1：使用kubectl命令管理项目的生命周期

• 项目的生命周期：创建、发布、更新、回滚、删除

1.1.1：创建

• 创建一个nginx的pod

  [root@master ~]# kubectl run nginx-test --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-test created
  [root@master ~]# kubectl get pods -w	'//-w：动态查看'
  [root@master ~]# kubectl  get pods -o wide	'//查看资源创建在那个节点上'
  [root@master ~]# kubectl get all	'//查看更详细信息：副本资源和控制器资源'
  [root@master ~]# kubectl get deployment,replicaset	'//仅查询pod资源的两个项'
  
  

1.1.2、发布

• [root@master ~]# kubectl get svc	'//查看原有的service服务'
  NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
  kubernetes   ClusterIP   10.0.0.1             443/TCP   92m
  [root@master ~]# kubectl expose deployment nginx-test --port=80 --target-port=80 --name=nginx-service --type=NodePort	'//将刚刚创建的暴露出来'
  service/nginx-service exposed
  [root@master ~]# kubectl get svc	'//再次查看'
  NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
  kubernetes      ClusterIP   10.0.0.1             443/TCP        92m
  nginx-service   NodePort    10.0.0.176           80:36355/TCP   3s
  [root@master ~]# kubectl get pods -o wide	'//查看pods在哪个节点上'
  NAME                          READY   STATUS    RESTARTS   AGE     IP            NODE              NOMINATED NODE
  nginx-dbddb74b8-5s6h7         1/1     Running   0          7d10h   172.17.26.2   192.168.233.132   
  nginx-test-59f87d55d6-4rvpl   1/1     Running   0          9m55s   172.17.4.3    192.168.233.133   
  nginx-test-59f87d55d6-qwrc6   1/1     Running   0          9m55s   172.17.4.2    192.168.233.133   
  nginx-test-59f87d55d6-xhtpb   1/1     Running   0          9m55s   172.17.26.4   192.168.233.132   
  [root@master ~]# kubectl get endpoints	'//查看pod资源的endpoint'
  NAME            ENDPOINTS                                    AGE
  kubernetes      192.168.233.130:6443,192.168.233.131:6443    93m
  nginx-service   172.17.26.4:80,172.17.4.2:80,172.17.4.3:80   38s
  
  

• 可以查看资源对象的缩写

  [root@master dashboard]# kubectl api-resources
  
  

• pod资源的调度

  当我们创建多个pod、service资源时，kube-proxy会做负载均衡，此时我们通过访问任意node节点ip可以访问所有的资源

  kubernetes中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kubernetes1.8之后加入了ipvs

  [root@node01 ~]# yum -y install ipvsadm 
  [root@node01 ~]# ipvsadm -L -n	'//查看调度'
  IP Virtual Server version 1.2.1 (size=4096)
  Prot LocalAddress:Port Scheduler Flags
    -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
  TCP  127.0.0.1:30005 rr
    -> 172.17.26.3:8443             Masq    1      0          0         
  TCP  127.0.0.1:36355 rr	'//发现可以访问本地地址可以自动轮询给三个pod资源，node02也是一样的'
    -> 172.17.4.2:80                Masq    1      0          0         
    -> 172.17.4.3:80                Masq    1      0          0         
    -> 172.17.26.4:80               Masq    1      0          0         
  
   
  

• 访问网页，查看日志

[root@master ~]# kubectl logs nginx-test-59f87d55d6-4rvpl
[root@master ~]# kubectl logs nginx-test-59f87d55d6-qwrc6
[root@master ~]# kubectl logs nginx-test-59f87d55d6-xhtpb	'//网页只访问了一次，所以只有一个pod资源有日志'
    ...省略内容
172.17.26.1 - - [08/May/2020:04:03:06 +0000] "GET /favicon.ico HTTP/1.1" 404 556 "http://192.168.233.132:36355/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36" "-"

1.1.3：更新

• 开发者模式查看版本号（我使用的是谷歌浏览器）

  

  [root@master ~]# kubectl set image deployment/nginx-test nginx-test=nginx:1.13 	'//更新版本'
  deployment.extensions/nginx-test image updated
  [root@master ~]# kubectl get pods -w	'//动态查看'
  '//容器的更新：滚动更新，容器只有删除和创建，没有重启的'
  

• 重新访问网页，再次查看版本

  

1.1.4：回滚

• 查看历史状态

  [root@master ~]# kubectl rollout history deployment/nginx-test
  deployment.extensions/nginx-test 
  REVISION  CHANGE-CAUSE
  1         
  2         
  

• 执行回滚

  [root@master ~]# kubectl rollout undo deployment/nginx-test
  deployment.extensions/nginx-test
  [root@master ~]# kubectl get pods -w	'//动态查看'
  
  

• 检查回滚状态

  

1.1.5：删除

• 删除不仅仅是pod，还有service

  [root@master ~]# kubectl delete deployment/nginx-test
  deployment.extensions "nginx-test" deleted
  [root@master ~]# kubectl get pods -w
  NAME                          READY   STATUS        RESTARTS   AGE
  nginx-dbddb74b8-5s6h7         1/1     Running       0          7d10h
  nginx-test-59f87d55d6-xgbrd   0/1     Terminating   0          3m13s
  nginx-test-59f87d55d6-zs5nf   0/1     Terminating   0          2m59s
  nginx-test-59f87d55d6-zs5nf   0/1   Terminating   0     3m4s
  nginx-test-59f87d55d6-zs5nf   0/1   Terminating   0     3m4s
  nginx-test-59f87d55d6-xgbrd   0/1   Terminating   0     3m18s
  nginx-test-59f87d55d6-xgbrd   0/1   Terminating   0     3m18s
  ^C[root@master ~]# kubectl get pods 	'//再次查看pod资源'
  NAME                    READY   STATUS    RESTARTS   AGE
  nginx-dbddb74b8-5s6h7   1/1     Running   0          7d10h
  [root@master ~]# kubectl get svc	'//查看service'
  NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
  kubernetes      ClusterIP   10.0.0.1             443/TCP        137m
  nginx-service   NodePort    10.0.0.176           80:36355/TCP   44m
  [root@master ~]# kubectl delete svc/nginx-service	'//删除service'
  service "nginx-service" deleted
  [root@master ~]# kubectl get svc	'//重新查看'
  NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
  kubernetes   ClusterIP   10.0.0.1             443/TCP   137m
  
  

1.2：其他常规操作

• 查看资源的详细信息

  [root@master ~]# kubectl get all
  NAME                        READY   STATUS    RESTARTS   AGE
  pod/nginx-dbddb74b8-5s6h7   1/1     Running   0          7d11h
  
  NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
  service/kubernetes   ClusterIP   10.0.0.1             443/TCP   163m
  
  NAME                    DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
  deployment.apps/nginx   1         1         1            1           7d11h
  
  NAME                              DESIRED   CURRENT   READY   AGE
  replicaset.apps/nginx-dbddb74b8   1         1         1       7d11h
  
  

• 查看service资源

  [root@master ~]# kubectl describe service/kubernetes
  Name:              kubernetes
  Namespace:         default
  Labels:            component=apiserver
                     provider=kubernetes
  Annotations:       
  Selector:          
  Type:              ClusterIP
  IP:                10.0.0.1
  Port:              https  443/TCP
  TargetPort:        6443/TCP
  Endpoints:         192.168.233.130:6443,192.168.233.131:6443
  Session Affinity:  None
  Events:            
  
  

• 查看deployment资源

  [root@master ~]# kubectl describe deployment.apps/nginx
  Name:                   nginx
  Namespace:              default
  CreationTimestamp:      Fri, 01 May 2020 01:31:30 +0800
  Labels:                 run=nginx
  Annotations:            deployment.kubernetes.io/revision: 1
  Selector:               run=nginx
  Replicas:               1 desired | 1 updated | 1 total | 1 available | 0 unavailable
  StrategyType:           RollingUpdate
  MinReadySeconds:        0
  RollingUpdateStrategy:  25% max unavailable, 25% max surge
  Pod Template:
    Labels:  run=nginx
    Containers:
     nginx:
      Image:        nginx
      Port:         
      Host Port:    
      Environment:  
      Mounts:       
    Volumes:        
  Conditions:
    Type           Status  Reason
    ----           ------  ------
    Available      True    MinimumReplicasAvailable
    Progressing    True    NewReplicaSetAvailable
  OldReplicaSets:  
  NewReplicaSet:   nginx-dbddb74b8 (1/1 replicas created)
  Events:          
  
  

• 进入pod

  [root@master ~]# kubectl exec -it nginx-dbddb74b8-5s6h7 bash
  root@nginx-dbddb74b8-5s6h7:/# ls
  bin   dev  home  lib64	mnt  proc  run	 srv  tmp  var
  boot  etc  lib	 media	opt  root  sbin  sys  usr
  root@nginx-dbddb74b8-5s6h7:/# exit 
  exit
  
  

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