BYO docker

Bring your own docker

It’s easy to get started with OpenShift whether that be using our app templates or bringing your existing docker assets. In this quick lab we will deploy app using an exisiting docker image. OpenShift will create an image stream for the image as well as deploy and manage containers based on that image. And we will dig into the details to show how all that works.

Let’s point OpenShift to an existing built docker image

Goto the terminal and type the following:

$ oc new-app kubernetes/guestbook

The output should show something similar to below:

--> Found docker image a49fe18 (17 months old) from docker Hub for "kubernetes/guestbook"
    * An image stream will be created as "guestbook:latest" that will track this image
    * This image will be deployed in deployment config "guestbook"
    * Port 3000/tcp will be load balanced by service "guestbook"
--> Creating resources with label app=guestbook ...
    ImageStream "guestbook" created
    DeploymentConfig "guestbook" created
    Service "guestbook" created
--> Success
    Run 'oc status' to view your app.

We can browse our project details with the command line

Try typing the following to see what is available to ‘get’:

$ oc get

Now let’s look at what our image stream has in it

$ oc get is

$ oc describe is/guestbook

An image stream can be used to automatically perform an action, such as updating a deployment, when a new image, such as a new version of the guestbook image, is created.

The app is running in a pod, let’s look at that

$ oc describe pods

We can see those details using the web console too

Let’s look at the image stream.

Click on "Browse", then click "Image Streams"

This shows a list of all image streams within the project.

Now click on the guestbook image stream

You should see something similar to this:

Does this guestbook do anything?

Good catch, your service is running but there is no way for users to access it yet. We can fix that with the web console or the command line, you decide which you’d rather do from the steps below.

Web Console Steps

To expose via the web console, click on "Overview" to get to this view:

Notice there is no exposed route

Click on the "Create Route" link

This is where you could specify route parameters, but we will just use the defaults.

Click "Create"

Alternatively: CLI Steps

In the command line type this:

$ oc expose service guestbook

You can also create secured HTTPS routes, but that’s an advanced topic for a later lab

Test out the guestbook webapp

Notice that in the web console overview, you now have a URL in the service box. There is no database setup, but you can see the webapp running by clicking the route you just exposed.

Click the link in the service box

You should see:

Good work, let’s clean this up

Let’s clean up all this to get ready for the next lab:

$ oc delete all --all

Summary

In this lab you’ve deployed an example docker image, pulled from docker hub, into a pod running in OpenShift. You exposed a route for clients to access that service via thier web browsers. And you learned how to get and describe resources using the command line and the web console. Hopefully, this basic lab also helped to get you familiar with using the CLI and navigating within the web console.