True-to-production development is critical when you create cloud-native applications, and what better way to develop those applications than directly in the cloud! The Open Liberty devfile stack allows you to do just that by providing a simple yet robust Open Liberty development experience directly in a Kubernetes or OpenShift cluster. The devfile stack does the heavy lifting by allowing you to focus on your code as if it were running right on your laptop.
Check out a quick demo:
OpenShift Do (odo) is the mechanism that’s used to drive the Open Liberty stack. It’s a straightforward CLI tool that you can use to create stack projects and interact directly with a Kubernetes or OpenShift cluster. Unlike
oc, odo abstracts away the complexity of the underlying infrastructure and helps developers focus on their applications.
Try it out
After you install odo, you can use the Open Liberty stack to either create a new Open Liberty starter application or initialize an existing application as a stack project. In this blog post, we’ll use the devfile-stack-intro project as a starting point:
$ git clone -b blog-demo [email protected]:OpenLiberty/devfile-stack-intro.git && \ cd devfile-stack-intro
This application is a basic JAX-RS sample that uses Maven, Open Liberty, and MicroProfile.
Log in to your OpenShift cluster and create an odo component:
$ odo create java-openliberty my-ol-component
You will notice that a
devfile.yaml file has been downloaded in the project root from the default devfile registry. This devfile is the brains behind the Open Liberty stack and outlines how the application is built, run, and deployed using the stack’s development image.
devfile-stack-intro application is now initialized with odo and ready to deploy:
$ odo push
Just like that, the application is pushed to your cluster. There’s no need to build an image, create a deployment, or run any custom commands. The stack and odo do everything behind the scenes. You can check the output to make sure that your application is up and ready for use:
$ odo log
To access the application, the Open Liberty stack creates a default URL for your deployment named
ep1. You can find that URL in the URL list:
$ odo url list Found the following URLs for component my-ol-component NAME STATE URL PORT SECURE KIND ep1 Pushed http://ep1-my-ol-component-my-project.apps.awisniew.cp.fyre.ibm.com 9080 false route
Open a browser to this URL and append
/api/resource to the end of the URL for the REST endpoint, for example,
http://ep1-my-ol-component-my-project.apps.awisniew.cp.fyre.ibm.com/api/resource. You should see the following screen:
If you’re deploying to generic Kubernetes, you might need to create a URL by using a configured Ingress domain, for example,
odo url create --host <my-ingress-domain>, and then push your changes again.
Not only is the application running in OpenShift, it is also running in dev mode so it’s ready to pick up any changes that you make. Each time you make a change, you can either re-issue the
odo push command to sync your local changes with your remote cluster, or odo can watch for changes automatically:
$ odo watch
Now, let’s make a change to the REST API. Open
src/main/java/dev/odo/sample/StarterResource and change the
getRequest() String response to "Open Liberty is awesome!"
Refresh your browser. The application that’s running in OpenShift is automatically updated!