This getting started experience walks you through the simplest way to get a sample project up and running on OKD. There are a few different ways to launch images within a project, but this topic focuses on the quickest and easiest method.
If this is the first part of the documentation you have read, and you are unfamiliar with the core concepts of OKD version 3 (v3), you might want to start by reading about what’s new. This version of OKD is significantly different from version 2 (v2).
OKD 3 provides out of the box a set of languages and databases for developers with corresponding implementations and tutorials that allow you to kickstart your application development. Language support centers around the Quickstart templates, which in turn leverage builder images.
|Language||Implementations and Tutorials|
Other images provided by OKD include:
To help illustrate constructing such applications, the following sections guide you through creating a project that contains a sample Node.js application that will serve a welcome page and the current hit count (stored in a database).
This topic discusses both Quickstart and Instant App templates and applications. Quickstarts provide a starting point for application development, but they rely on your development to create a useful application. In contrast, Instant Apps like Jenkins are instantly usable.
Review the browser versions and operating systems that can be used to access the web console.
Before you can get started:
You must be able to access a running instance of OKD. If you do not have access, contact your cluster administrator.
Your instance must be pre-configured by a cluster administrator with the Instant App templates and builder images. If they are not available, direct your cluster administrator to the Loading the Default Image Streams and Templates topic.
You must have the OKD CLI downloaded and installed.
Visit the Ruby example page while you are logged in to GitHub.
This topic follows the Ruby example, but you can follow along using any of the language examples provided in the OKD GitHub project.
You are redirected to your new fork.
Copy the clone URL for your fork.
Clone the repository to your local machine.
To create an application, you must first create a new project, then select an InstantApp template. From there, OKD begins the build process and creates a new deployment.
Visit the OKD web console in your browser. The web console uses a self-signed certificate, so if prompted, continue past a browser warning.
Log in using the username and password recommended to you by your administrator.
To create a new project, click New Project.
Type a unique name, display name, and description for the new project.
The web console’s welcome screen loads.
The Select Image or Template page gives you the option to create from a publicly accessible git repository, or from a template:
If creating a new project did not automatically redirect you to the Select Image or Template page, you might need to click Add to Project.
Click Browse, then select ruby from the drop-down list.
Click the ruby:latest builder image.
Type a name for your application, and specify the Git Repository URL, which is
Optionally, click Show advanced routing, build, and deployment options, though by default this example application automatically creates a route, webhook trigger, and build change triggers.
After creation, some of these settings can be modified from the web console by clicking Browse, Builds, select your build, then click Actions, and either Edit or Edit YAML.
Creating your application might take some time. You can follow along on the Overview page of the web console to see the new resources being created, and watch the progress of the build and deployment.
While the Ruby pod is being created, its status is shown as pending. The Ruby pod then starts up and displays its newly-assigned IP address. When the Ruby pod is running, the build is complete.
If your DNS is correctly configured, then your new application can be accessed using a web browser. If you cannot access your application, then speak with your system administrator.
To view your new application:
In the web console, view the overview page to determine the web address for the application. For example, under SERVICE: RUBY-EX you should see something similar to:
Visit the web address for your new application.
You forked the source code for this application from the OKD GitHub repository. Therefore, you can use a webhook to automatically trigger a rebuild of your application whenever you push code changes to your forked repository.
To set up a webhook for your application:
From the Web Console, navigate to the project containing your application.
Click the Browse tab, then click Builds.
Click your build name, then click the Configuration tab.
Click next to GitHub webhook URL to copy your webhook payload URL.
Navigate to your forked repository on GitHub, then click Settings.
Click Webhooks & Services.
Click Add webhook.
Paste your webhook URL into the Payload URL field.
Click Add webhook to save.
GitHub now attempts to send a ping payload to your OKD server to ensure that communication is successful. If you see a green check mark appear next to your webhook URL, then it is correctly configured. Hover your mouse over the check mark to see the status of the last delivery.
The next time you push a code change to your forked repository, your application will automatically rebuild.
To work locally and then push changes to your application:
On your local machine, use a text editor to change the sample application’s source for the file ruby-ex/config.ru
Make a code change that will be visible from within your application. For example: on line 229, change the title from
Welcome to your Ruby application on OpenShift to
This is my Awesome OpenShift Application, then save your changes.
Commit the change in git, and push the change to your fork.
If your webhook is correctly configured, your application will immediately rebuild itself based on your changes. Once the rebuild is successful, view your updated application using the route that was created earlier.
Now going forward, all you need to do is push code updates and OKD handles the rest.
You may find it useful to manually rebuild an image if your webhook is not working, or if a build fails and you do not want to change the code before restarting the build. To manually rebuild the image based on your latest committed change to your forked repository:
Click the Browse tab, then click Builds.
Find your build, then click Start Build.