Move Guide toic to Tasks: kubectl exec.

reviewable/pr2533/r4
steveperry-53 2017-02-13 15:03:37 -08:00 committed by steveperry-53
parent f348728060
commit 2e3758381d
4 changed files with 165 additions and 66 deletions

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@ -6,6 +6,7 @@ toc:
- title: Using the Kubectl Command-Line
section:
- docs/tasks/kubectl/list-all-running-container-images.md
- docs/tasks/kubectl/get-shell-running-container.md
- title: Configuring Pods and Containers
section:

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@ -0,0 +1,148 @@
---
assignees:
- caesarxuchao
- mikedanese
title: Getting a Shell to a Running Container
---
{% 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/kubectl/shell-demo.yaml" %}
Create the Pod:
```shell
kubectl create -f https://k8s.io/docs/tasks/kubectl/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/v1.5/#exec)
{% endcapture %}
{% include templates/task.md %}

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@ -0,0 +1,14 @@
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

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@ -5,70 +5,6 @@ assignees:
title: Running Commands in a Container with kubectl exec
---
Developers can use `kubectl exec` to run commands in a container. This guide demonstrates two use cases.
{% include user-guide-content-moved.md %}
## Using kubectl exec to check the environment variables of a container
Kubernetes exposes [services](/docs/user-guide/services/#environment-variables) through environment variables. It is convenient to check these environment variables using `kubectl exec`.
We first create a pod and a service,
```shell
$ kubectl create -f examples/guestbook/redis-master-controller.yaml
$ kubectl create -f examples/guestbook/redis-master-service.yaml
```
wait until the pod is Running and Ready,
```shell
$ kubectl get pod
NAME READY REASON RESTARTS AGE
redis-master-ft9ex 1/1 Running 0 12s
```
then we can check the environment variables of the pod,
```shell
$ kubectl exec redis-master-ft9ex env
...
REDIS_MASTER_SERVICE_PORT=6379
REDIS_MASTER_SERVICE_HOST=10.0.0.219
...
```
We can use these environment variables in applications to find the service.
## Using kubectl exec to check the mounted volumes
It is convenient to use `kubectl exec` to check if the volumes are mounted as expected.
We first create a Pod with a volume mounted at /data/redis,
```shell
kubectl create -f docs/user-guide/walkthrough/pod-redis.yaml
```
wait until the pod is Running and Ready,
```shell
$ kubectl get pods
NAME READY REASON RESTARTS AGE
storage 1/1 Running 0 1m
```
we then use `kubectl exec` to verify that the volume is mounted at /data/redis,
```shell
$ kubectl exec storage ls /data
redis
```
## Using kubectl exec to open a bash terminal in a pod
After all, open a terminal in a pod is the most direct way to introspect the pod. Assuming the pod/storage is still running, run
```shell
$ kubectl exec -ti storage -- bash
root@storage:/data#
```
This gets you a terminal.
[Getting a Shell to a Running Container](/docs/tasks/kubectl/get-shell-running-container/)