--- title: Docker 用户的 kubectl 指南 content_template: templates/concept reviewers: - bgrant0607 - brendandburns - thockin --- {{% capture overview %}} 您可以使用 Kubernetes 命令行工具 kubectl 与 API 服务器交互。如果您熟悉 Docker 命令行工具,那么使用 kubectl 非常简单。 但是,Docker 命令和 kubectl 命令之间存在一些差异。以下部分介绍了 Docker 子命令,并描述了等效的 kubectl 命令。 {{% /capture %}} {{% capture body %}} ## docker run 要运行 nginx Deployment 并公开该 Deployment,请参考 [kubectl run](/docs/reference/generated/kubectl/kubectl-commands/#run)。 docker: ```shell $ docker run -d --restart=always -e DOMAIN=cluster --name nginx-app -p 80:80 nginx 55c103fa129692154a7652490236fee9be47d70a8dd562281ae7d2f9a339a6db $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 55c103fa1296 nginx "nginx -g 'daemon of…" 9 seconds ago Up 9 seconds 0.0.0.0:80->80/tcp nginx-app ``` kubectl: ```shell # 启动 Pod 运行 nginx $ kubectl run --image=nginx nginx-app --port=80 --env="DOMAIN=cluster" deployment "nginx-app" created ``` {{< note >}} `kubectl` 命令打印创建或变更的资源类型和名称,以便可以在后续的命令中使用。可以在创建 Deployment 后公开一个新 Service。 {{< /note >}} ```shell # 通过 Service 暴露端口 $ kubectl expose deployment nginx-app --port=80 --name=nginx-http service "nginx-http" exposed ``` 通过使用 kubectl,您可以创建一个[Deployment](/docs/concepts/workloads/controllers/deployment/) 来确保 N 个 Pod 运行 nginx,其中 N 是声明中规定的副本数,默认值为 1。 您还可以使用与 Pod 标签匹配的选择器创建 [服务](/docs/concepts/services-networking/service/)。 有关详细信息,请参阅[使用服务访问群集中的应用](/docs/tasks/access-application-cluster/service-access-application-cluster)。 默认情况下,镜像在后台运行,类似于 `docker run -d ...`。要在前台运行,请使用: ```shell kubectl run [-i] [--tty] --attach --image= ``` 不像 `docker run ...`,如果您指定了 `--attach` 参数,那您实际上就为其关联了 `stdin`、`stdout` 和 `stderr`。 无法控制关联哪个流(`docker -a ...`)。 因为 kubectl run 命令会为容器启动 Deployment,所以如果使用 Ctrl+C 终止关联的进程,则 Deployment 将重新启动,这与 `docker run -it` 不同。 要销毁 Deployment 及其 Pod,需要运行 `kubectl delete deployment `。 ## docker ps 要列出当前正在运行的内容,请参考 [kubectl get](/docs/reference/generated/kubectl/kubectl-commands/#get)。 docker: ```shell $ docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 14636241935f ubuntu:16.04 "echo test" 5 seconds ago Exited (0) 5 seconds ago cocky_fermi 55c103fa1296 nginx "nginx -g 'daemon of…" About a minute ago Up About a minute 0.0.0.0:80->80/tcp nginx-app ``` kubectl: ```shell $ kubectl get po NAME READY STATUS RESTARTS AGE nginx-app-8df569cb7-4gd89 1/1 Running 0 3m ubuntu 0/1 Completed 0 20s ``` ## docker attach 要和已在容器中运行的进程建立联系,请参见 [kubectl attach](/docs/reference/generated/kubectl/kubectl-commands/#attach)。 docker: ```shell $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 55c103fa1296 nginx "nginx -g 'daemon of…" 5 minutes ago Up 5 minutes 0.0.0.0:80->80/tcp nginx-app $ docker attach 55c103fa1296 ... ``` kubectl: ```shell $ kubectl get pods NAME READY STATUS RESTARTS AGE nginx-app-5jyvm 1/1 Running 0 10m $ kubectl attach -it nginx-app-5jyvm ... ``` 要退出容器,可以键入转义序列 Ctrl+P,然后键入 Ctrl+Q。 ## docker exec 要在容器中执行命令,请参见 [kubectl exec](/docs/reference/generated/kubectl/kubectl-commands/#exec)。 docker: ```shell $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 55c103fa1296 nginx "nginx -g 'daemon of…" 6 minutes ago Up 6 minutes 0.0.0.0:80->80/tcp nginx-app $ docker exec 55c103fa1296 cat /etc/hostname 55c103fa1296 ``` kubectl: ```shell $ kubectl get po NAME READY STATUS RESTARTS AGE nginx-app-5jyvm 1/1 Running 0 10m $ kubectl exec nginx-app-5jyvm -- cat /etc/hostname nginx-app-5jyvm ``` 使用交互命令。 docker: ```shell $ docker exec -ti 55c103fa1296 /bin/sh # exit ``` kubectl: ```shell $ kubectl exec -ti nginx-app-5jyvm -- /bin/sh # exit ``` 更多信息,请参见[获取正在运行的容器的 shell](/docs/tasks/debug-application-cluster/get-shell-running-container/)。 ## docker logs 要跟踪正在运行的进程的 stdout/stderr,请参见 [kubectl logs](/docs/reference/generated/kubectl/kubectl-commands/#logs)。 docker: ```shell $ docker logs -f a9e 192.168.9.1 - - [14/Jul/2015:01:04:02 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.35.0" "-" 192.168.9.1 - - [14/Jul/2015:01:04:03 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.35.0" "-" ``` kubectl: ```shell $ kubectl logs -f nginx-app-zibvs 10.240.63.110 - - [14/Jul/2015:01:09:01 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.26.0" "-" 10.240.63.110 - - [14/Jul/2015:01:09:02 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.26.0" "-" ``` Pod 和容器之间有细微的区别;默认情况下,如果进程退出,Pod 不会终止。相反,Pod 会重新启动进程。 这与 docker run 的选项 `--restart=always` 类似,不过有一点不同。 在 Docker 中,每次进程调用的输出都是串联的,但是对于 Kubernetes,每次调用是独立的。 要查看 Kubernetes 上一次运行的输出,请执行以下操作: ```shell $ kubectl logs --previous nginx-app-zibvs 10.240.63.110 - - [14/Jul/2015:01:09:01 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.26.0" "-" 10.240.63.110 - - [14/Jul/2015:01:09:02 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.26.0" "-" ``` 更多信息请参考[日志架构](/docs/concepts/cluster-administration/logging/)。 ## docker stop 和 docker rm 要停止并删除一个运行中的进程,请参考 [kubectl delete](/docs/reference/generated/kubectl/kubectl-commands/#delete)。 docker: ```shell $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES a9ec34d98787 nginx "nginx -g 'daemon of" 22 hours ago Up 22 hours 0.0.0.0:80->80/tcp, 443/tcp nginx-app $ docker stop a9ec34d98787 a9ec34d98787 $ docker rm a9ec34d98787 a9ec34d98787 ``` kubectl: ```shell $ kubectl get deployment nginx-app NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE nginx-app 1 1 1 1 2m $ kubectl get po -l run=nginx-app NAME READY STATUS RESTARTS AGE nginx-app-2883164633-aklf7 1/1 Running 0 2m $ kubectl delete deployment nginx-app deployment "nginx-app" deleted $ kubectl get po -l run=nginx-app # 什么都没返回 ``` {{< note >}} 使用 kubectl 时,不会直接删除 Pod,必须先删除拥有该 Pod 的 Deployment。如果直接删除 Pod,Deployment 将重新创建 Pod。 {{< /note >}} ## docker login 在 kubectl 中没有与 docker login 直接对应的操作。如果您有兴趣在 Kubernetes 中使用私有仓库,请参考 [使用私有仓库](/docs/concepts/containers/images/#using-a-private-registry)。 ## docker version 要获取客户端和服务器的版本,请参考 [kubectl version](/docs/reference/generated/kubectl/kubectl-commands/#version)。 docker: ```shell $ docker version Client version: 1.7.0 Client API version: 1.19 Go version (client): go1.4.2 Git commit (client): 0baf609 OS/Arch (client): linux/amd64 Server version: 1.7.0 Server API version: 1.19 Go version (server): go1.4.2 Git commit (server): 0baf609 OS/Arch (server): linux/amd64 ``` kubectl: ```shell $ kubectl version Client Version: version.Info{Major:"1", Minor:"6", GitVersion:"v1.6.9+a3d1dfa6f4335", GitCommit:"9b77fed11a9843ce3780f70dd251e92901c43072", GitTreeState:"dirty", BuildDate:"2017-08-29T20:32:58Z", OpenPaasKubernetesVersion:"v1.03.02", GoVersion:"go1.7.5", Compiler:"gc", Platform:"linux/amd64"} Server Version: version.Info{Major:"1", Minor:"6", GitVersion:"v1.6.9+a3d1dfa6f4335", GitCommit:"9b77fed11a9843ce3780f70dd251e92901c43072", GitTreeState:"dirty", BuildDate:"2017-08-29T20:32:58Z", OpenPaasKubernetesVersion:"v1.03.02", GoVersion:"go1.7.5", Compiler:"gc", Platform:"linux/amd64"} ``` ## docker info 要获取有关环境和配置的其他信息,请参阅 [kubectl cluster-info](/docs/reference/generated/kubectl/kubectl-commands/#cluster-info)。 docker: ```shell $ docker info Containers: 40 Images: 168 Storage Driver: aufs Root Dir: /usr/local/google/docker/aufs Backing Filesystem: extfs Dirs: 248 Dirperm1 Supported: false Execution Driver: native-0.2 Logging Driver: json-file Kernel Version: 3.13.0-53-generic Operating System: Ubuntu 14.04.2 LTS CPUs: 12 Total Memory: 31.32 GiB Name: k8s-is-fun.mtv.corp.google.com ID: ADUV:GCYR:B3VJ:HMPO:LNPQ:KD5S:YKFQ:76VN:IANZ:7TFV:ZBF4:BYJO WARNING: No swap limit support ``` kubectl: ```shell $ kubectl cluster-info Kubernetes master is running at https://108.59.85.141 KubeDNS is running at https://108.59.85.141/api/v1/namespaces/kube-system/services/kube-dns/proxy kubernetes-dashboard is running at https://108.59.85.141/api/v1/namespaces/kube-system/services/kubernetes-dashboard/proxy Grafana is running at https://108.59.85.141/api/v1/namespaces/kube-system/services/monitoring-grafana/proxy Heapster is running at https://108.59.85.141/api/v1/namespaces/kube-system/services/monitoring-heapster/proxy InfluxDB is running at https://108.59.85.141/api/v1/namespaces/kube-system/services/monitoring-influxdb/proxy ``` {{% /capture %}}