{% capture overview %} This page shows how to use an Init Container to initialize a Pod before an application Container runs.

{% endcapture %}

{% capture prerequisites %}

{% include task-tutorial-prereqs.md %}

{% endcapture %}

{% capture steps %}

Creating a Pod that has an Init Container

In this exercise you create a Pod that has one application Container and one Init Container. The init container runs to completion before the application container starts.

Here is the configuration file for the Pod:

{% include code.html language="yaml" file="init-containers.yaml" ghlink="/docs/tasks/configure-pod-container/init-containers.yaml" %}

In the configuration file, you can see that the Pod has a Volume that the init container and the application container share.

The init container mounts the shared Volume at /work-dir, and the application container mounts the shared Volume at /usr/share/nginx/html. The init container runs the following command and then terminates:

 wget -O /work-dir/index.html http://kubernetes.io

Notice that the init container writes the index.html file in the root directory of the nginx server.

Create the Pod:

kubectl create -f http://k8s.io/docs/tasks/configure-pod-container/init-containers.yaml

Verify that the nginx container is running:

kubectl get pod init-demo

The output shows that the nginx container is running:

nginx     1/1       Running   0          43m

Get a shell into the nginx container running in the init-demo Pod:

kubectl exec -it init-demo -- /bin/bash

In your shell, send a GET request to the nginx server:

root@nginx:~# apt-get update
root@nginx:~# apt-get install curl
root@nginx:~# curl localhost

The output shows that nginx is serving the web page that was written by the init container:

<!Doctype html>
<html id="home">

"url": "http://kubernetes.io/"}</script>
  <p>Kubernetes is open source giving you the freedom to take advantage ...</p>

{% endcapture %}

{% capture whatsnext %}

{% endcapture %}

{% include templates/task.md %}