how-to-create-applications.md

Creating Applications in Kubernetes Application Navigator

You can create projects and applications in Kubernetes Application Navigator with the OpenShift console.

Before you begin

Ensure that you install an OpenShift environment with kAppNav installed. You need access to the console and also need to have a user account that is authorized to create projects and applications.

About this task

Many names, labels, and resources are defined and used by convention with Kubernetes. Depending on which development tools that you use, some names, labels, and resources can vary. Kubernetes Application Navigator relies on matching these names, labels, and resources to define and display your application. Because of this condition, you need to understand how your application is deployed, what resources are used, and how it is named and labeled. The exact names, labels, and resource kinds can vary based on your application and environment.

Step 1: Create a simple Node.js application

1. Log in to your OpenShift Console.

2. From the Service Catalog, create a new Node.js project.

   • Select a Node.js project from either the catalog ...
   • ... or search for it.

3. Use the project creation dialog box to create a new project.

4. Create the Node.js application.

   • In the Configuration section of the project creation dialog box, enter the details to create a new project.
     • Under Git Repository, click Try Sample Repository.
     • Click Create.

5. Close the dialog box and navigate to the newly created My Node Project.

6. Navigate to the My Node Project project view. If necessary, wait for the build to complete.

7. When the build is complete and the pod is deployed, access the URL of the application.

8. The application is now deployed and receiving traffic.

Step 2: Add the application in Kubernetes Application Navigator

To display the application with Kubernetes Application Navigator, you can create an Application Custom Resource. You can create an Application Custom Resource by using either the kAppNav GUI or the kubectl CLI.

Creating the Application Custom Resource through the GUI

1. Go to the kAppNav UI and click the Create Applications button.

2. On the General tab, specify the application name and namespace.

   • The Name value can be anything and does not need to match the name of the application. The Namespace value is the namespace that the application belongs to.

3. On the Selectors tab, specify the app label name and the application name that appears under Value.

   • The label name is provided by convention and the application name is provided when the application is created.

4. On the Kinds tab, specify two resource kinds in the resources group.

5. Click create.

   • The application is created. The status might display as Unknown for a few moments until it changes to Normal. The Unknown status occurs while Kubernetes Application Navigator is interrogating the resources to determine the overall status.

6. Navigate into the my-node-app application to see the details and components that compose the application.

Editing the Application Custom Resource through the GUI

You can add more resources, such as Services and Routes, to the application components by editing the Application Custom Resource.

1. Navigate into the application. From the action menu, click Edit to modify the Application Custom Resource as a JSON file.

2. Add more Kinds to the componentKinds list and click Save.

   • { "group": "resources", "kind": "Service" }, { "group": "resources", "kind": "Route"},

3. Kubernetes Application Navigator automatically updates the display to show the added resources. The new resources might display as Unknown under Status for a few moments until the status changes to Normal.

Creating the Application Custom Resource through the CLI

Important: If you do not create the Application Custom Resource through the GUI before you create the Application Custom Resource through the CLI, the output of the steps might look different.

1. Optional: Use the following command to ensure that the pods in the my-node-app are running: kubectl get pods -n my-node-project.

   # kubectl get pods -n my-node-project
   NAME                  READY     STATUS      RESTARTS   AGE
   my-node-app-1-build   0/1       Completed   0          31m
   my-node-app-1-mlvgl   1/1       Running     0          31m
   

2. Create an Application Custom Resource YAML file.

   • The YAML file describes the specific Kubernetes resources that are included in the Application that you define.
   • Application Custom Resource YAML my-node-app-cr.yaml:

   apiVersion: app.k8s.io/v1beta1
   kind: Application
   metadata:
     name: my-node-app2
     namespace: my-node-project
   spec:
     componentKinds:
     - group: resources
       kind: Pod
     - group: resources
       kind: DeploymentConfig
     selector:
       matchLabels:
         app: my-node-app
   

3. Create the my-node-app-crd.yamlfile Application Custom Resource with the following command: kubectl apply -f my-node-app-cr.yaml

   # kubectl apply -f my-node-app-crd.yaml 
   application.app.k8s.io/my-node-app2 created
   

4. Confirm that the Application Custom Resource is created by using the following command: kubectl get application -n my-node-project

   • The my-node-app resource is created when you create the Application Custom Resource through the GUI.

   # kubectl get application -n my-node-project
   NAME           AGE
   my-node-app    48m
   my-node-app2   19m
   

5. Navigate to Kubernetes Application Navigator to see the my-node-app and my-node-app2 resources.

Editing the Application Custom Resource through the CLI

You can add more resources, such as Services and Routes, to the application components by editing the Application Custom Resource.

1. Update the my-node-app-cr.yaml file to include the Service and Route

apiVersion: app.k8s.io/v1beta1
kind: Application
metadata:
  name: my-node-app2
  namespace: my-node-project
spec:
  componentKinds:
  - group: resources
    kind: Pod
  - group: resources
    kind: DeploymentConfig
  - group: resources
    kind: Service
  - group: resources
    kind: Route
  selector:
    matchLabels:
      app: my-node-app

2. Apply the updated my-node-app-cr.yaml file with the following command: kubectl apply -f my-node-app-cr.yaml

• The Application Custom Resource is configured:

# kubectl apply -f my-node-app-cr.yaml 
application.app.k8s.io/my-node-app2 configured

3. Navigate to Kubernetes Application Navigator to see the changes.