--- title: kubectl for Docker Users reviewers: - bgrant0607 - brendandburns - thockin --- You can use the Kubernetes command line tool kubectl to interact with the api. You can use kubectl if you are familiar with docker-cli. However, there are a few differences in the docker-cli commands and the kubectl commands. Each of the following section details a docker subcommand and explains the kubectl equivalent. {{< toc >}} #### docker run To run an nginx Deployment and expose the Deployment, see [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 # start the pod running nginx $ kubectl run --image=nginx nginx-app --port=80 --env="DOMAIN=cluster" deployment "nginx-app" created ``` {{< note >}} **Note:** `kubectl` commands print the type and name of the resource created or mutated, which can then be used in subsequent commands. You can expose a new Service after a Deployment is created. {{< /note >}} ```shell # expose a port through with a service $ kubectl expose deployment nginx-app --port=80 --name=nginx-http service "nginx-http" exposed ``` By using kubectl, you can create a [Deployment](/docs/concepts/workloads/controllers/deployment/) to ensure that N pods are running nginx, where N is the number of replicas stated in the spec and defaults to 1. You can also create a [service](/docs/concepts/services-networking/service/) with a selector that matches the pod labels. For more information, see [Use a Service to Access an Application in a Cluster](/docs/tasks/access-application-cluster/service-access-application-cluster). By default images run in the background, similar to `docker run -d ...`. To run things in the foreground, use: ```shell kubectl run [-i] [--tty] --attach --image= ``` Unlike `docker run ...`, if you specify `--attach`, then you attach `stdin`, `stdout` and `stderr`. You cannot control which streams are attached (`docker -a ...`). To detach from the container, you can type the escape sequence Ctrl+P followed by Ctrl+Q. Because the kubectl run command starts a Deployment for the container, the Deployment restarts if you terminate the attached process by using Ctrl+C, unlike `docker run -it`. To destroy the Deployment and its pods you need to run `kubectl delete deployment `. #### docker ps To list what is currently running, see [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 -a NAME READY STATUS RESTARTS AGE nginx-app-8df569cb7-4gd89 1/1 Running 0 3m ubuntu 0/1 Completed 0 20s ``` #### docker attach To attach a process that is already running in a container, see [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 ... ``` To detach from the container, you can type the escape sequence Ctrl+P followed by Ctrl+Q. #### docker exec To execute a command in a container, see [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 ``` To use interactive commands. docker: ```shell $ docker exec -ti 55c103fa1296 /bin/sh # exit ``` kubectl: ```shell $ kubectl exec -ti nginx-app-5jyvm -- /bin/sh # exit ``` For more information, see [Get a Shell to a Running Container](/docs/tasks/debug-application-cluster/get-shell-running-container/). #### docker logs To follow stdout/stderr of a process that is running, see [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" "-" ``` There is a slight difference between pods and containers; by default pods do not terminate if their processes exit. Instead the pods restart the process. This is similar to the docker run option `--restart=always` with one major difference. In docker, the output for each invocation of the process is concatenated, but for Kubernetes, each invocation is separate. To see the output from a previous run in Kubernetes, do this: ```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" "-" ``` For more information, see [Logging Architecture](/docs/concepts/cluster-administration/logging/). #### docker stop and docker rm To stop and delete a running process, see [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 # Return nothing ``` {{< note >}} **Note:** When you use kubectl, you don't delete the pod directly.You have to fiirst delete the Deployment that owns the pod. If you delete the pod directly, the Deployment recreates the pod. {{< /note >}} #### docker login There is no direct analog of `docker login` in kubectl. If you are interested in using Kubernetes with a private registry, see [Using a Private Registry](/docs/concepts/containers/images/#using-a-private-registry). #### docker version To get the version of client and server, see [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 To get miscellaneous information about the environment and configuration, see [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 ```