Move to debugging section: shell. (#3677)

docs/tasks/debug-application-cluster/get-shell-running-container.md

@@ -0,0 +1,153 @@
+---
+assignees:
+- caesarxuchao
+- mikedanese
+title: Getting a Shell to a Running Container
+redirect_from:
+- "/docs/user-guide/getting-into-containers/"
+- "/docs/user-guide/getting-into-containers.html"
+- "/docs/tasks/kubectl/get-shell-running-container/"
+- "/docs/tasks/kubectl/get-shell-running-container.html"
+---
+
+{% capture overview %}
+
+This page shows how to use `kubectl exec` to get a shell to a
+running Container.
+
+{% endcapture %}
+
+
+{% capture prerequisites %}
+
+{% include task-tutorial-prereqs.md %}
+
+{% endcapture %}
+
+
+{% capture steps %}
+
+## Getting a shell to a Container
+
+In this exercise, you create a Pod that has one Container. The Container
+runs the nginx image. Here is the configuration file for the Pod:
+
+{% include code.html language="yaml" file="shell-demo.yaml" ghlink="/docs/tasks/debug-application-cluster/shell-demo.yaml" %}
+
+Create the Pod:
+
+```shell
+kubectl create -f https://k8s.io/docs/tasks/debug-application-cluster/shell-demo.yaml
+```
+
+Verify that the Container is running:
+
+```shell
+kubectl get pod shell-demo
+```
+
+Get a shell to the running Container:
+
+```shell
+kubectl exec -it shell-demo -- /bin/bash
+```
+
+In your shell, list the running processes:
+
+```shell
+root@shell-demo:/# ps aux
+```
+
+In your shell, list the nginx processes:
+
+```shell
+root@shell-demo:/# ps aux | grep nginx
+```
+
+In your shell, experiment with other commands. Here are
+some examples:
+
+```shell
+root@shell-demo:/# ls /
+root@shell-demo:/# cat /proc/mounts
+root@shell-demo:/# cat /proc/1/maps
+root@shell-demo:/# apt-get update
+root@shell-demo:/# apt-get install tcpdump
+root@shell-demo:/# tcpdump
+root@shell-demo:/# apt-get install lsof
+root@shell-demo:/# lsof
+```
+
+## Writing the root page for nginx
+
+Look 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:
+
+```shell
+root@shell-demo:/# echo Hello shell demo > /usr/share/nginx/html/index.html
+```
+
+In your shell, send a GET request to the nginx server:
+
+```shell
+root@shell-demo:/# apt-get update
+root@shell-demo:/# apt-get install curl
+root@shell-demo:/# curl localhost
+```
+
+The output shows the text that you wrote to the `index.html` file:
+
+```shell
+Hello shell demo
+```
+
+When you are finished with your shell, enter `exit`.
+
+## Running individual commands in a Container
+
+In an ordinary command window, not your shell, list the environment
+variables in the running Container:
+
+```shell
+kubectl exec shell-demo env
+```
+
+Experiment running other commands. Here are some examples:
+
+```shell
+kubectl exec shell-demo ps aux
+kubectl exec shell-demo ls /
+kubectl exec shell-demo cat /proc/1/mounts
+```
+
+{% endcapture %}
+
+{% capture discussion %}
+
+## Opening a shell when a Pod has more than one Container
+
+If 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.
+
+```shell
+kubectl exec -it my-pod --container main-app -- /bin/bash
+```
+
+{% endcapture %}
+
+
+{% capture whatsnext %}
+
+* [kubectl exec](/docs/user-guide/kubectl/v1.6/#exec)
+
+{% endcapture %}
+
+
+{% include templates/task.md %}