Creating a single-component application with odo - Developer <strong>cli</strong> (odo) | <strong>cli</strong> tools

Prerequisites
Creating a project
Creating a Node.js application with odo
Modifying your application code
Adding storage to the application components
Adding a custom builder to specify a build image
Connecting your application to multiple services using OpenShift Service Catalog
Deleting an application

With odo, you can create and deploy applications on clusters.

Prerequisites

odo is installed.
You have a running cluster. You can use CodeReady Containers (CRC) to deploy a local cluster quickly.

Creating a project

Create a project to keep your source code, tests, and libraries organized in a separate single unit.

Procedure

Create a project:

$ odo project create myproject
 ✓  Project 'myproject' is ready for use
 ✓  New project created and now using project : myproject

Creating a Node.js application with odo

To create a Node.js component, download the Node.js application and push the source code to your cluster with odo.

Procedure

Create a directory for your components:

$ mkdir my_components $$ cd my_components

Download the example Node.js application:

$ git clone https://github.com/openshift/nodejs-ex

Change the current directory to the directory with your application:
```
$ cd <directory_name>
```
Add a component of the type Node.js to your application:
```
$ odo create nodejs
```
By default, the latest image is used. You can also explicitly specify an image version by using odo create openshift/nodejs:8.
Push the initial source code to the component:
```
$ odo push
```
Your component is now deployed to OpenShift Container Platform.
Create a URL and add an entry in the local configuration file as follows:
```
$ odo url create --port 8080
```
Push the changes. This creates a URL on the cluster.
```
$ odo push
```
List the URLs to check the desired URL for the component.
```
$ odo url list
```
View your deployed application using the generated URL.
```
$ curl <url>
```

Modifying your application code

You can modify your application code and have the changes applied to your application on OpenShift Container Platform.

Edit one of the layout files within the Node.js directory with your preferred text editor.
Update your component:
```
$ odo push
```
Refresh your application in the browser to see the changes.

Adding storage to the application components

Persistent storage keeps data available between restarts of odo. You can add storage to your components with the odo storage command.

Procedure

Add storage to your components:

$ odo storage create nodestorage --path=/opt/app-root/src/storage/ --size=1Gi

Your component now has 1 GB storage.

Adding a custom builder to specify a build image

With OpenShift Container Platform, you can add a custom image to bridge the gap between the creation of custom images.

The following example demonstrates the successful import and use of the redhat-openjdk-18 image:

Prerequisites

The OpenShift cli (oc) is installed.

Procedure

Import the image into OpenShift Container Platform:

$ oc import-image openjdk18 \
--from=registry.access.redhat.com/redhat-openjdk-18/openjdk18-openshift \
--confirm

Tag the image to make it accessible to odo:

$ oc annotate istag/openjdk18:latest tags=builder

Deploy the image with odo:

$ odo create openjdk18 --git \
https://github.com/openshift-evangelists/Wild-West-Backend

Connecting your application to multiple services using OpenShift Service Catalog

The OpenShift service catalog is an implementation of the Open Service Broker API (OSB API) for Kubernetes. You can use it to connect applications deployed in OpenShift Container Platform to a variety of services.

Prerequisites

You have a running OpenShift Container Platform cluster.
The service catalog is installed and enabled on your cluster.

Procedure

To list the services:
```
$ odo catalog list services
```
To use service catalog-related operations:
```
$ odo service <verb> <service_name>
```

Deleting an application

Deleting an application will delete all components associated with the application.

Procedure

List the applications in the current project:

$ odo app list
    The project '<project_name>' has the following applications:
    NAME
    app

List the components associated with the applications. These components will be deleted with the application:

$ odo component list
    APP     NAME                      TYPE       SOURCE        STATE
    app     nodejs-nodejs-ex-elyf     nodejs     file://./     Pushed

Delete the application:

$ odo app delete <application_name>
    ? Are you sure you want to delete the application: <application_name> from project: <project_name>

Confirm the deletion with Y. You can suppress the confirmation prompt using the -f flag.