Kubernetes 简明教程

Kubernetes - Kubectl Commands

Kubectl 控制 Kubernetes 群集。它是 Kubernetes 的关键组件之一，它在设置完成时在任意计算机上的工作站上运行。它有能力管理群集中的节点。

Kubectl controls the Kubernetes Cluster. It is one of the key components of Kubernetes which runs on the workstation on any machine when the setup is done. It has the capability to manage the nodes in the cluster.

Kubectl 命令用于交互和管理 Kubernetes 对象和群集。在本章中，我们将讨论通过 kubectl 在 Kubernetes 中使用的一些命令。

Kubectl commands are used to interact and manage Kubernetes objects and the cluster. In this chapter, we will discuss a few commands used in Kubernetes via kubectl.

kubectl annotate − 它会更新资源上的注释。

kubectl annotate − It updates the annotation on a resource.

$kubectl annotate [--overwrite] (-f FILENAME | TYPE NAME) KEY_1=VAL_1 ...
KEY_N = VAL_N [--resource-version = version]

例如，

For example,

kubectl annotate pods tomcat description = 'my frontend'

kubectl api-versions - 打印集群上受支持的 API 版本。

kubectl api-versions − It prints the supported versions of API on the cluster.

$ kubectl api-version;

kubectl apply - 具有通过文件或标准输入配置资源的功能。

kubectl apply − It has the capability to configure a resource by file or stdin.

$ kubectl apply –f <filename>

kubectl attach - 将东西附加到正在运行的容器中。

kubectl attach − This attaches things to the running container.

$ kubectl attach <pod> –c <container>
$ kubectl attach 123456-7890 -c tomcat-conatiner

kubectl autoscale - 用于自动扩展部署、副本集、副本控制器等已定义的 Pod。

kubectl autoscale − This is used to auto scale pods which are defined such as Deployment, replica set, Replication Controller.

$ kubectl autoscale (-f FILENAME | TYPE NAME | TYPE/NAME) [--min = MINPODS] --
max = MAXPODS [--cpu-percent = CPU] [flags]
$ kubectl autoscale deployment foo --min = 2 --max = 10

kubectl cluster-info - 显示集群信息。

kubectl cluster-info − It displays the cluster Info.

$ kubectl cluster-info

kubectl cluster-info dump - 转储与集群相关的相关信息，用于调试和诊断。

kubectl cluster-info dump − It dumps relevant information regarding cluster for debugging and diagnosis.

$ kubectl cluster-info dump
$ kubectl cluster-info dump --output-directory = /path/to/cluster-state

kubectl config - 修改 kubeconfig 文件。

kubectl config − Modifies the kubeconfig file.

$ kubectl config <SUBCOMMAD>
$ kubectl config –-kubeconfig <String of File name>

kubectl config current-context - 显示当前内容。

kubectl config current-context − It displays the current context.

$ kubectl config current-context
#deploys the current context

kubectl config delete-cluster - 从 kubeconfig 中删除指定集群。

kubectl config delete-cluster − Deletes the specified cluster from kubeconfig.

$ kubectl config delete-cluster <Cluster Name>

kubectl config delete-context - 从 kubeconfig 中删除指定上下文。

kubectl config delete-context − Deletes a specified context from kubeconfig.

$ kubectl config delete-context <Context Name>

kubectl config get-clusters - 显示 kubeconfig 中定义的集群。

kubectl config get-clusters − Displays cluster defined in the kubeconfig.

$ kubectl config get-cluster
$ kubectl config get-cluster <Cluser Name>

kubectl config get-contexts - 描述一个或多个上下文。

kubectl config get-contexts − Describes one or many contexts.

$ kubectl config get-context <Context Name>

kubectl config set-cluster - 设置 Kubernetes 中的集群条目。

kubectl config set-cluster − Sets the cluster entry in Kubernetes.

$ kubectl config set-cluster NAME [--server = server] [--certificateauthority =
path/to/certificate/authority] [--insecure-skip-tls-verify = true]

kubectl config set-context - 在 kubernetes 入口点中设置上下文条目。

kubectl config set-context − Sets a context entry in kubernetes entrypoint.

$ kubectl config set-context NAME [--cluster = cluster_nickname] [--
user = user_nickname] [--namespace = namespace]
$ kubectl config set-context prod –user = vipin-mishra

kubectl config set-credentials - 在 kubeconfig 中设置用户条目。

kubectl config set-credentials − Sets a user entry in kubeconfig.

$ kubectl config set-credentials cluster-admin --username = vipin --
password = uXFGweU9l35qcif

kubectl config set - 设置 kubeconfig 文件中的一个单独值。

kubectl config set − Sets an individual value in kubeconfig file.

$ kubectl config set PROPERTY_NAME PROPERTY_VALUE

kubectl config unset - 取消设置 kubectl 中特定的组件。

kubectl config unset − It unsets a specific component in kubectl.

$ kubectl config unset PROPERTY_NAME PROPERTY_VALUE

kubectl config use-context - 设置 kubectl 文件中的当前上下文。

kubectl config use-context − Sets the current context in kubectl file.

$ kubectl config use-context <Context Name>

kubectl config view

kubectl config view

$ kubectl config view
$ kubectl config view –o jsonpath='{.users[?(@.name == "e2e")].user.password}'

kubectl cp − 从容器中复制文件和目录并将其复制到容器中。

kubectl cp − Copy files and directories to and from containers.

$ kubectl cp <Files from source> <Files to Destinatiion>
$ kubectl cp /tmp/foo <some-pod>:/tmp/bar -c <specific-container>

kubectl create − 通过文件名或标准输入创建资源。为此，JSON 或 YAML 格式均可接受。

kubectl create − To create resource by filename of or stdin. To do this, JSON or YAML formats are accepted.

$ kubectl create –f <File Name>
$ cat <file name> | kubectl create –f -

同样，我们可以按照使用 create 命令和 kubectl 列出的内容创建多个内容。

In the same way, we can create multiple things as listed using the create command along with kubectl.

  1. deployment

  2. namespace

  3. quota

  4. secret docker-registry

  5. secret

  6. secret generic

  7. secret tls

  8. serviceaccount

  9. service clusterip

  10. service loadbalancer

  11. service nodeport

kubectl delete − 通过文件名称、标准输入、资源和名称删除资源。

kubectl delete − Deletes resources by file name, stdin, resource and names.

$ kubectl delete –f ([-f FILENAME] | TYPE [(NAME | -l label | --all)])

kubectl describe − 描述 kubernetes 中的任何特定资源。显示资源或一组资源的详细信息。

kubectl describe − Describes any particular resource in kubernetes. Shows details of resource or a group of resources.

$ kubectl describe <type> <type name>
$ kubectl describe pod tomcat

kubectl drain − 用于对节点进行维护而将其耗尽。为维护准备节点。这会将该节点标记为不可用，这样就不应该将其分配给将创建的新容器。

kubectl drain − This is used to drain a node for maintenance purpose. It prepares the node for maintenance. This will mark the node as unavailable so that it should not be assigned with a new container which will be created.

$ kubectl drain tomcat –force

kubectl edit − 用于终止服务器上的资源。这允许直接编辑可以通过命令行工具接收的资源。

kubectl edit − It is used to end the resources on the server. This allows to directly edit a resource which one can receive via the command line tool.

$ kubectl edit <Resource/Name | File Name)
Ex.
$ kubectl edit rc/tomcat

kubectl exec − 有助于在容器中执行命令。

kubectl exec − This helps to execute a command in the container.

$ kubectl exec POD <-c CONTAINER > -- COMMAND < args...>
$ kubectl exec tomcat 123-5-456 date

kubectl expose − 用于将 Kubernetes 对象（例如 pod、副本控制器和服务）公开为新的 Kubernetes 服务。这具有通过正在运行的容器或 yaml 文件公开它的功能。

kubectl expose − This is used to expose the Kubernetes objects such as pod, replication controller, and service as a new Kubernetes service. This has the capability to expose it via a running container or from a yaml file.

$ kubectl expose (-f FILENAME | TYPE NAME) [--port=port] [--protocol = TCP|UDP]
[--target-port = number-or-name] [--name = name] [--external-ip = external-ip-ofservice]
[--type = type]
$ kubectl expose rc tomcat –-port=80 –target-port = 30000
$ kubectl expose –f tomcat.yaml –port = 80 –target-port =

kubectl get − 此命令能够获取有关 Kubernetes 资源的群集数据。

kubectl get − This command is capable of fetching data on the cluster about the Kubernetes resources.

$ kubectl get [(-o|--output=)json|yaml|wide|custom-columns=...|custom-columnsfile=...|
go-template=...|go-template-file=...|jsonpath=...|jsonpath-file=...]
(TYPE [NAME | -l label] | TYPE/NAME ...) [flags]

例如，

For example,

$ kubectl get pod <pod name>
$ kubectl get service <Service name>

kubectl logs − 用于获取 pod 中容器的日志。打印日志可以是定义 pod 中的容器名称。如果 POD 只有一个容器，则无需定义其名称。

kubectl logs − They are used to get the logs of the container in a pod. Printing the logs can be defining the container name in the pod. If the POD has only one container there is no need to define its name.

$ kubectl logs [-f] [-p] POD [-c CONTAINER]
Example
$ kubectl logs tomcat.
$ kubectl logs –p –c tomcat.8

kubectl port-forward − 用于将一个或多个本地端口转发到 pod。

kubectl port-forward − They are used to forward one or more local port to pods.

$ kubectl port-forward POD [LOCAL_PORT:]REMOTE_PORT
[...[LOCAL_PORT_N:]REMOTE_PORT_N]
$ kubectl port-forward tomcat 3000 4000
$ kubectl port-forward tomcat 3000:5000

kubectl replace − 能够按文件名称或 stdin 替换资源。

kubectl replace − Capable of replacing a resource by file name or stdin.

$ kubectl replace -f FILENAME
$ kubectl replace –f tomcat.yml
$ cat tomcat.yml | kubectl replace –f -

kubectl rolling-update − 对副本控制器执行滚动更新。通过一次更新一个 POD，使用一个新的副本控制器替换指定的副本控制器。

kubectl rolling-update − Performs a rolling update on a replication controller. Replaces the specified replication controller with a new replication controller by updating a POD at a time.

$ kubectl rolling-update OLD_CONTROLLER_NAME ([NEW_CONTROLLER_NAME] --
image = NEW_CONTAINER_IMAGE | -f NEW_CONTROLLER_SPEC)
$ kubectl rolling-update frontend-v1 –f freontend-v2.yaml

kubectl rollout − 能够管理部署的推出。

kubectl rollout − It is capable of managing the rollout of deployment.

$ Kubectl rollout <Sub Command>
$ kubectl rollout undo deployment/tomcat

除了上述内容之外，我们还可以使用推出执行多项任务，例如：

Apart from the above, we can perform multiple tasks using the rollout such as −

  1. rollout history

  2. rollout pause

  3. rollout resume

  4. rollout status

  5. rollout undo

kubectl run − Run 命令能够在 Kubernetes 群集上运行映像。

kubectl run − Run command has the capability to run an image on the Kubernetes cluster.

$ kubectl run NAME --image = image [--env = "key = value"] [--port = port] [--
replicas = replicas] [--dry-run = bool] [--overrides = inline-json] [--command] --
[COMMAND] [args...]
$ kubectl run tomcat --image = tomcat:7.0
$ kubectl run tomcat –-image = tomcat:7.0 –port = 5000

kubectl scale − 它会扩展 Kubernetes 部署、副本集、副本控制器或作业的大小。

kubectl scale − It will scale the size of Kubernetes Deployments, ReplicaSet, Replication Controller, or job.

$ kubectl scale [--resource-version = version] [--current-replicas = count] --
replicas = COUNT (-f FILENAME | TYPE NAME )
$ kubectl scale –-replica = 3 rs/tomcat
$ kubectl scale –replica = 3 tomcat.yaml

kubectl set image − 更新 pod 模板的映像。

kubectl set image − It updates the image of a pod template.

$ kubectl set image (-f FILENAME | TYPE NAME)
CONTAINER_NAME_1 = CONTAINER_IMAGE_1 ... CONTAINER_NAME_N = CONTAINER_IMAGE_N
$ kubectl set image deployment/tomcat busybox = busybox ngnix = ngnix:1.9.1
$ kubectl set image deployments, rc tomcat = tomcat6.0 --all

kubectl set resources − 用于设置资源的内容。它使用 pod 模板更新对象上的资源/限制。

kubectl set resources − It is used to set the content of the resource. It updates resource/limits on object with pod template.

$ kubectl set resources (-f FILENAME | TYPE NAME) ([--limits = LIMITS & --
requests = REQUESTS]
$ kubectl set resources deployment tomcat -c = tomcat --
limits = cpu = 200m,memory = 512Mi

kubectl top node − 显示 CPU/内存/存储使用情况。top 命令允许你查看节点的资源消耗。

kubectl top node − It displays CPU/Memory/Storage usage. The top command allows you to see the resource consumption for nodes.

$ kubectl top node [node Name]

这个相同的命令还可以与 pod 一起使用。

The same command can be used with a pod as well.