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Creating applications using the Developer perspective

The Developer perspective in the web console provides you the following options from the Add view to create applications and associated services and deploy them on OpenShift Container Platform:

Add View

  • From Git: Use this option to import an existing codebase in a Git repository to create, build, and deploy an application on OpenShift Container Platform.

  • Container Image: Use existing images from an image stream or registry to deploy it on to OpenShift Container Platform.

  • From Catalog: Explore the Developer Catalog to select the required applications, services, or source to image builders and add it to your project.

  • From Dockerfile: Import a dockerfile from your Git repository to build and deploy an application.

  • YAML: Use the editor to add YAML or JSON definitions to create and modify resources.

  • Database: See the Developer Catalog to select the required database service and add it to your application.

Serverless options in the Developer perspective are displayed only if the OpenShift Serverless Operator is installed in your cluster.

Prerequisites

To create applications using the Developer perspective ensure that:

To create serverless applications, in addition to the preceeding prerequisites, ensure that:

Importing a codebase from Git to create an application

The following procedure walks you through the Import from Git option in the Developer perspective to create an application.

Create, build, and deploy an application on OpenShift Container Platform using an existing codebase in GitHub as follows:

Procedure

  1. In the Add view, click From Git to see the Import from git form.

  2. In the Git section, enter the Git repository URL for the codebase you want to use to create an application. For example, enter the URL of this sample Node.js application https://github.com/sclorg/nodejs-ex. The URL is then validated.

  3. Optional: You can click Show Advanced Git Options to add details such as:

    • Git Reference to point to code in a specific branch, tag, or commit to be used to build the application.

    • Context Dir to specify the subdirectory for the application source code you want to use to build the application.

    • Source Secret to create a Secret Name with credentials for pulling your source code from a private repository.

  4. In the Builder section, after the URL is validated, an appropriate builder image is detected, indicated by a star, and automatically selected. For the https://github.com/sclorg/nodejs-ex Git URL, the Node.js builder image is selected by default. If required, you can change the version using the Builder Image Version drop-down list.

  5. In the General section:

    1. In the Application field, enter a unique name for the application grouping, for example, myapp. Ensure that the application name is unique in a namespace.

    2. The Name field to identify the resources created for this application is automatically populated based on the Git repository URL.

      The resource name must be unique in a namespace. Modify the resource name if you get an error.

  6. In the Resources section, select:

    • Deployment, to create an application in plain Kubernetes style.

    • Deployment Config, to create an OpenShift style application.

    • Knative Service, to create a microservice.

    The Knative Service option is displayed in the Import from git form only if the Serverless Operator is installed in your cluster. For further details refer to documentation on installing OpenShift Serverless.

  7. In the Advanced Options section, the Create a route to the application is selected by default so that you can access your application using a publicly available URL. You can clear the check box if you do not want to expose your application on a public route.

  8. Optional: You can use the following advanced options to further customize your application:

    Routing

    Click the Routing link to:

    • Customize the hostname for the route.

    • Specify the path the router watches.

    • Select the target port for the traffic from the drop-down list.

    • Secure your route by selecting the Secure Route check box. Select the required TLS termination type and set a policy for insecure traffic from the respective drop-down lists.

      For serverless applications, the Knative Service manages all the routing options above. However, you can customize the target port for traffic, if required. If the target port is not specified, the default port of 8080 is used.

    Build and Deployment Configuration

    Click the Build Configuration and Deployment Configuration links to see the respective configuration options. Some of the options are selected by default; you can customize them further by adding the necessary triggers and environment variables. For serverless applications, the Deployment Configuration option is not displayed as the Knative configuration resource maintains the desired state for your deployment instead of a DeploymentConfig.

    Scaling

    Click the Scaling link to define the number of Pods or instances of the application you want to deploy initially.

    For serverless applications, you can:

    • Set the upper and lower limit for the number of pods that can be set by the autoscaler. If the lower limit is not specified, it defaults to zero.

    • Define the soft limit for the required number of concurrent requests per instance of the application at a given time. It is the recommended configuration for autoscaling. If not specified, it takes the value specified in the cluster configuration.

    • Define the hard limit for the number of concurrent requests allowed per instance of the application at a given time. This is configured in the revision template. If not specified, it defaults to the value specified in the cluster configuration.

    Resource Limit

    Click the Resource Limit link to set the amount of CPU and Memory resources a container is guaranteed or allowed to use when running.

    Labels

    Click the Labels link to add custom labels to your application.

  9. Click Create to create the application and see its build status in the Topology view.