Chapter 7. Managing applications on an edge device

Procedure

1. Define the functionality of the application in a file called podman-compose.yaml that follows the Podman Compose specification:

   • Create a file called Containerfile with the following content:

     FROM scratch 

     1

     
     COPY podman-compose.yaml /podman-compose.yaml
     LABEL appType="compose" 

     2

     Copy to Clipboard Toggle word wrap

     1

     Embed the compose file in a scratch container.

     2

     Add the appType=compose label.

2. Build and push the container image to your OCI registry:

   1. Define the image repository that you have permissions to write to by running the following command:

      OCI_IMAGE_REPO=quai.io/<your_org>/<your_image>

      Copy to Clipboard Toggle word wrap

   2. Define the image tag by running the following command:

      OCI_IMAGE_TAG=v1

      Copy to Clipboard Toggle word wrap

   3. Build the application container image by running the following command:

      podman build -t ${OCI_IMAGE_REPO}:${OCI_IMAGE_TAG} .

      Copy to Clipboard Toggle word wrap

   4. Push the container image by running the following command:

      podman push ${OCI_IMAGE_REPO}:${OCI_IMAGE_TAG} .

      Copy to Clipboard Toggle word wrap

Procedure

1. Specify the application package that you want to deploy in the spec.applications field in the Device resource:

   apiVersion: flightctl.io/v1alpha1
   kind: Device
   metadata:
     name: <device_name>
   spec:
   [...]
     applications:
     - name: wordpress 

   1

   
       image: quay.io/rhem-demos/wordpress-app:latest 

   2

   
       envVars: 

   3

   
         WORDPRESS_DB_HOST: <database_host>
         WORDPRESS_DB_USER: <user_name>
         WORDPRESS_DB_PASSWORD: <password>
   [...]

   Copy to Clipboard Toggle word wrap

   1

   A user-defined name for the application that is used when the web console and the CLI list applications.

   2

   A reference to an application package in an OCI registry.

   3

   Optional. A list of key-value pairs that are passed to the deployment tool as environment variables or command line flags.

   Note

   For each application in the applications section of the device specification, you can find the corresponding device status information.

2. Verify the status of an application deployment on a device by inspecting the device status information by running the following command:

   flightctl get device/<your_device_id> -o yaml

   Copy to Clipboard Toggle word wrap

   See the following example output:

   [...]
   spec:
     applications:
     - name: example-app
       image: quay.io/flightctl-demos/example-app:v1
   status:
     applications:
     - name: example-app
       ready: 3/3
       restarts: 0
       status: Running
     applicationsSummary:
       info: All application workloads are healthy.
       status: Healthy
   [...]

   Copy to Clipboard Toggle word wrap