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2.3. kubectl - controls the Kubernetes cluster manager.

kubectl是Kubernetes的命令行管理工具

	
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         Take a replication controller, service, deployment or pod and expose it as a new Kubernetes Service
  run            Run a particular image on the cluster
  set            Set specific features on objects

Basic Commands (Intermediate):
  explain        Documentation of resources
  get            Display one or many resources
  edit           Edit a resource on the server
  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          Set a new size for a Deployment, ReplicaSet, Replication Controller, or Job
  autoscale      Auto-scale a Deployment, ReplicaSet, or ReplicationController

Cluster Management Commands:
  certificate    Modify certificate resources.
  cluster-info   Display cluster info
  top            Display Resource (CPU/Memory/Storage) usage.
  cordon         Mark node as unschedulable
  uncordon       Mark node as schedulable
  drain          Drain node in preparation for maintenance
  taint          Update the taints on one or more nodes

Troubleshooting and Debugging Commands:
  describe       Show details of a specific resource or group of resources
  logs           Print the logs for a container in a pod
  attach         Attach to a running container
  exec           Execute a command in a container
  port-forward   Forward one or more local ports to a pod
  proxy          Run a proxy to the Kubernetes API server
  cp             Copy files and directories to and from containers.
  auth           Inspect authorization

Advanced Commands:
  diff           Diff live version against would-be applied version
  apply          Apply a configuration to a resource by filename or stdin
  patch          Update field(s) of a resource using strategic merge patch
  replace        Replace a resource by filename or stdin
  wait           Experimental: Wait for a specific condition on one or many resources.
  convert        Convert config files between different API versions

Settings Commands:
  label          Update the labels on a resource
  annotate       Update the annotations on a resource
  completion     Output shell completion code for the specified shell (bash or zsh)

Other Commands:
  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         Modify kubeconfig files
  plugin         Provides utilities for interacting with plugins.
  version        Print the client and server version information

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).	
	
	

2.3.1. 如何从 docker 过渡到 kubectl 命令

docker run 命令

		
$ docker run -d --restart=always -e DOMAIN=cluster --name nginx -p 80:80 nginx		
		
		

kubectl 命令

		
$ kubectl run --image=nginx nginx-app --port=80 --env="DOMAIN=cluster"
$ kubectl expose deployment nginx-app --port=80 --name=nginx-http	
		
		

docker exec 命令

		
$ docker run -t -i ubuntu:14.10 /bin/bash
		
		

kubectl 命令

		
$ kubectl exec -ti nginx-app-5jyvm -- /bin/sh	
		
		

docker ps 命令

		
$ docker ps
		
		

kubectl 命令

		
$ kubectl get pods
NAME                        READY   STATUS    RESTARTS   AGE
mongodba-6d5d6ddf64-jw4fv   1/1     Running   0          16h

# kubectl exec -it mongodba-6d5d6ddf64-jw4fv bash		
		
		

2.3.2. 节点

		
[root@localhost ~]# kubectl get nodes
NAME       STATUS   ROLES    AGE   VERSION
minikube   Ready    master   23m   v1.13.2		
		
		

2.3.3. pod

		
[root@localhost ~]# kubectl get pod
NAME                              READY   STATUS    RESTARTS   AGE
hello-minikube-5c856cbf98-6vfvp   1/1     Running   0          6m59s
		
		

指定命名空间

		
[root@localhost ~]# kubectl get pod --namespace=kube-system
NAME                                   READY   STATUS    RESTARTS   AGE
coredns-86c58d9df4-2rfqf               1/1     Running   0          40m
coredns-86c58d9df4-wkb7l               1/1     Running   0          40m
etcd-minikube                          1/1     Running   0          40m
kube-addon-manager-minikube            1/1     Running   0          41m
kube-apiserver-minikube                1/1     Running   2          40m
kube-controller-manager-minikube       1/1     Running   6          40m
kube-proxy-brrdd                       1/1     Running   0          40m
kube-scheduler-minikube                1/1     Running   5          41m
kubernetes-dashboard-ccc79bfc9-dxcq2   1/1     Running   5          16m
storage-provisioner                    1/1     Running   0          39m		
		
		

2.3.4. pods

		
kubectl get pod <pod-name> -o wide		
kubectl get pods --all-namespaces
		
		
		
[root@localhost ~]# kubectl get pods --all-namespaces
NAMESPACE     NAME                                   READY   STATUS    RESTARTS   AGE
default       hello-minikube-5c856cbf98-6vfvp        1/1     Running   1          4d18h
kube-system   coredns-86c58d9df4-2rfqf               1/1     Running   51         4d18h
kube-system   coredns-86c58d9df4-wkb7l               1/1     Running   49         4d18h
kube-system   etcd-minikube                          1/1     Running   12         4d18h
kube-system   kube-addon-manager-minikube            1/1     Running   11         4d18h
kube-system   kube-apiserver-minikube                1/1     Running   74         4d18h
kube-system   kube-controller-manager-minikube       1/1     Running   31         4d18h
kube-system   kube-proxy-brrdd                       1/1     Running   1          4d18h
kube-system   kube-scheduler-minikube                1/1     Running   31         4d18h
kube-system   kubernetes-dashboard-ccc79bfc9-dxcq2   1/1     Running   7          4d17h
kube-system   storage-provisioner                    1/1     Running   2          4d18h		
		
		

2.3.5. 查询集群状态

		
[root@localhost ~]# kubectl get cs
NAME                 STATUS    MESSAGE              ERROR
controller-manager   Healthy   ok                   
scheduler            Healthy   ok                   
etcd-0               Healthy   {"health": "true"}   		
		
		

2.3.6. cluster-info

		
[root@localhost ~]# kubectl cluster-info
Kubernetes master is running at https://172.16.0.121:8443
KubeDNS is running at https://172.16.0.121:8443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.		
		
		

2.3.7. create

		
kubectl create -f https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml
kubectl get pods --namespace=kube-system		
		
		

2.3.7.1. 创建命名空间

创建 jenkins-namespace.yaml

			
apiVersion: v1
kind: Namespace
metadata:
  name: jenkins-project
			
			
			
$ kubectl create -f jenkins-namespace.yaml
namespace ”jenkins-project“ created			
			
			

2.3.8. edit

		
kubectl edit --namespace=kube-system rc kubernetes-dashboard		
		
		

2.3.9. config

		
[root@localhost ~]# kubectl config view
apiVersion: v1
clusters:
- cluster:
    certificate-authority: /root/.minikube/ca.crt
    server: https://172.16.0.121:8443
  name: minikube
contexts:
- context:
    cluster: minikube
    user: minikube
  name: minikube
current-context: minikube
kind: Config
preferences: {}
users:
- name: minikube
  user:
    client-certificate: /root/.minikube/client.crt
    client-key: /root/.minikube/client.key		
		
		

2.3.9.1. use-context

如果之前用其他方式运行Kubernetes,如 minikube, mircok8s 等等,可以使用下面命令切换。

			
$ kubectl config use-context docker-for-desktop		
			
			

2.3.10. nodes

		
[root@localhost ~]# kubectl get nodes
NAME       STATUS   ROLES    AGE    VERSION
minikube   Ready    master   119m   v1.13.2		
		
		

2.3.11. service

2.3.11.1. 列出服务

			
[root@localhost ~]# kubectl get service
NAME             TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
hello-minikube   NodePort    10.109.33.86   <none>        8080:30436/TCP   134m
kubernetes       ClusterIP   10.96.0.1      <none>        443/TCP          147m		
			
			

2.3.11.2. 删除服务

			
kubectl delete service hello-minikube			
			
			

2.3.11.3. 删除 pod

			
kubectl delete deployment hello-minikube			
			
			

2.3.12. 查看 pod 日志

		
kubectl logs <pod-name>
kubectl logs --previous <pod-name>		
		
		

2.3.13. 查看 Pod 的事件

		
kubectl describe pod <pod-name> 		
		
		

2.3.14. 执行 Shell

进入容器内部.

		
$ kubectl get pods
NAME                        READY   STATUS    RESTARTS   AGE
mongodba-6d5d6ddf64-jw4fv   1/1     Running   0          16h

$ kubectl exec -it mongodba-6d5d6ddf64-jw4fv bash