Creating applications by using devfiles with `odo` is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see https://access.redhat.com/support/offerings/techpreview/.

About the devfile in odo

The devfile is a portable file that describes your development environment. With the devfile, you can define a portable developmental environment without the need for reconfiguration.

With the devfile, you can describe your development environment, such as the source code, IDE tools, application runtimes, and predefined commands. To learn more about the devfile, see the devfile documentation.

With odo, you can create components from the devfiles. When creating a component by using a devfile, odo transforms the devfile into a workspace consisting of multiple containers that run on OKD, Kubernetes, or Docker. odo automatically uses the default devfile registry but users can add their own registries.

Creating a Java application by using a devfile

Prerequisites

  • You have installed odo.

  • You must know your ingress domain cluster name. Contact your cluster administrator if you do not know it. For example, apps-crc.testing is the cluster domain name for Red Hat CodeReady Containers.

  • You have enabled Experimental Mode in odo.

    • To enable Experimental Mode in odo preferences, run odo preference set Experimental true or use the environment variable odo config set --env ODO_EXPERIMENTAL=true

Creating a project

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

Procedure
  1. Log in to an OKD cluster:

    $ odo login -u developer -p developer
  2. Create a project:

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

Listing available devfile components

With odo, you can display all the components that are available for you on the cluster. Components that are available depend on the configuration of your cluster.

Procedure
  1. To list available devfile components on your cluster, run:

    $ odo catalog list components

    The output lists the available odo components:

    Odo Devfile Components:
    NAME                 DESCRIPTION                            REGISTRY
    java-maven           Upstream Maven and OpenJDK 11          DefaultDevfileRegistry
    java-openliberty     Open Liberty microservice in Java      DefaultDevfileRegistry
    java-quarkus         Upstream Quarkus with Java+GraalVM     DefaultDevfileRegistry
    java-springboot      Spring Boot® using Java                DefaultDevfileRegistry
    nodejs               Stack with NodeJS 12                   DefaultDevfileRegistry
    
    Odo OpenShift Components:
    NAME        PROJECT       TAGS                                                                           SUPPORTED
    java        openshift     11,8,latest                                                                    YES
    dotnet      openshift     2.1,3.1,latest                                                                 NO
    golang      openshift     1.13.4-ubi7,1.13.4-ubi8,latest                                                 NO
    httpd       openshift     2.4-el7,2.4-el8,latest                                                         NO
    nginx       openshift     1.14-el7,1.14-el8,1.16-el7,1.16-el8,latest                                     NO
    nodejs      openshift     10-ubi7,10-ubi8,12-ubi7,12-ubi8,latest                                         NO
    perl        openshift     5.26-el7,5.26-ubi8,5.30-el7,latest                                             NO
    php         openshift     7.2-ubi7,7.2-ubi8,7.3-ubi7,7.3-ubi8,latest                                     NO
    python      openshift     2.7-ubi7,2.7-ubi8,3.6-ubi7,3.6-ubi8,3.8-ubi7,3.8-ubi8,latest                   NO
    ruby        openshift     2.5-ubi7,2.5-ubi8,2.6-ubi7,2.6-ubi8,2.7-ubi7,latest                            NO
    wildfly     openshift     10.0,10.1,11.0,12.0,13.0,14.0,15.0,16.0,17.0,18.0,19.0,20.0,8.1,9.0,latest     NO

Deploying a Java application using a devfile

In this section, you will learn how to deploy a sample Java project that uses Maven and Java 8 JDK using a devfile.

Procedure
  1. Create a directory to store the source code of your component:

    $ mkdir <directory-name>
  2. Create a component configuration of Spring Boot component type named myspring and download its sample project:

    $ odo create java-spring-boot myspring --starter

    The previous command produces the following output:

    Experimental mode is enabled, use at your own risk
    
    Validation
    ✓  Checking devfile compatibility [195728ns]
    ✓  Creating a devfile component from registry: DefaultDevfileRegistry [170275ns]
    ✓  Validating devfile component [281940ns]
    
    Please use `odo push` command to create the component with source deployed

    The odo create command downloads the associated devfile.yaml file from the recorded devfile registries.

  3. List the contents of the directory to confirm that the devfile and the sample Java application were downloaded:

    $ ls

    The previous command produces the following output:

    README.md    devfile.yaml    pom.xml        src
  4. Create a URL to access the deployed component:

    $ odo url create --host apps-crc.testing

    The previous command produces the following output:

    ✓  URL myspring-8080.apps-crc.testing created for component: myspring
    
    To apply the URL configuration changes, please use odo push
    You must use your cluster host domain name when creating the URL.
  5. Push the component to the cluster:

    $ odo push

    The previous command produces the following output:

    Validation
     ✓  Validating the devfile [81808ns]
    
    Creating Kubernetes resources for component myspring
     ✓  Waiting for component to start [5s]
    
    Applying URL changes
     ✓  URL myspring-8080: http://myspring-8080.apps-crc.testing created
    
    Syncing to component myspring
     ✓  Checking files for pushing [2ms]
     ✓  Syncing files to the component [1s]
    
    Executing devfile commands for component myspring
     ✓  Executing devbuild command "/artifacts/bin/build-container-full.sh" [1m]
     ✓  Executing devrun command "/artifacts/bin/start-server.sh" [2s]
    
    Pushing devfile component myspring
     ✓  Changes successfully pushed to component
  6. List the URLs of the component to verify that the component was pushed successfully:

    $ odo url list

    The previous command produces the following output:

    Found the following URLs for component myspring
    NAME              URL                                       PORT     SECURE
    myspring-8080     http://myspring-8080.apps-crc.testing     8080     false
  7. View your deployed application by using the generated URL:

    $ curl http://myspring-8080.apps-crc.testing

Converting an S2I component into a devfile component

With odo, you can create both Source-to-Image (S2I) and devfile components. If you have an existing S2I component, you can convert it into a devfile component using the odo utils command.

Procedure

Run all the commands from the S2I component directory.

  1. Run the odo utils convert-to-devfile command, which creates devfile.yaml and env.yaml based on your component:

    $ odo utils convert-to-devfile
  2. Push the component to your cluster:

    $ odo push

    If the devfile component deployment failed, delete it by running: $ odo delete -a

  3. Verify that the devfile component deployed successfully:

    $ odo list
  4. Delete the S2I component:

    $ odo delete --s2i