# Get a Shell to a Running Container

Get a Shell to a Running ContainerThis page shows how to use kubectl exec to get a shell to a running container.Before you beginYou need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:iximiuz LabsKillercodaKodeKloudPlay with KubernetesGetting a shell to a containerIn this exercise, you create a Pod that has one container. The container runs the nginx image. Here is the configuration file for the Pod:application/shell-demo.yaml apiVersion: v1 kind: Pod metadata: name: shell-demo spec: volumes: - name: shared-data emptyDir: {} containers: - name: nginx image: nginx volumeMounts: - name: shared-data mountPath: /usr/share/nginx/html hostNetwork: true dnsPolicy: Default Create the Pod:kubectl apply -f https://k8s.io/examples/application/shell-demo.yaml Verify that the container is running:kubectl get pod shell-demo Get a shell to the running container:kubectl exec --stdin --tty shell-demo -- /bin/bash Note:The double dash (--) separates the arguments you want to pass to the command from the kubectl arguments.In your shell, list the root directory:# Run this inside the container ls / In your shell, experiment with other commands. Here are some examples:# You can run these example commands inside the container ls / cat /proc/mounts cat /proc/1/maps apt-get update apt-get install -y tcpdump tcpdump apt-get install -y lsof lsof apt-get install -y procps ps aux ps aux | grep nginx Writing the root page for nginxLook again at the configuration file for your Pod. The Pod has an emptyDir volume, and the container mounts the volume at /usr/share/nginx/html.In your shell, create an index.html file in the /usr/share/nginx/html directory:# Run this inside the container echo 'Hello shell demo' > /usr/share/nginx/html/index.html In your shell, send a GET request to the nginx server:# Run this in the shell inside your container apt-get update apt-get install curl curl http://localhost/ The output shows the text that you wrote to the index.html file:Hello shell demo When you are finished with your shell, enter exit.exit # To quit the shell in the container Running individual commands in a containerIn an ordinary command window, not your shell, list the environment variables in the running container:kubectl exec shell-demo -- env Experiment with running other commands. Here are some examples:kubectl exec shell-demo -- ps aux kubectl exec shell-demo -- ls / kubectl exec shell-demo -- cat /proc/1/mounts Opening a shell when a Pod has more than one containerIf a Pod has more than one container, use --container or -c to specify a container in the kubectl exec command. For example, suppose you have a Pod named my-pod, and the Pod has two containers named main-app and helper-app. The following command would open a shell to the main-app container.kubectl exec -i -t my-pod --container main-app -- /bin/bash Note:The short options -i and -t are the same as the long options --stdin and --ttyWhat's nextRead about kubectl exec