Remove an application

Removing an application will free quota resources and enable you to deploy other applications. OAM applications are defined by an application configuration entity that links all the components that form the application applying traits and scopes. To remove an application, you will need to delete all associated entities.

Prerequirements

Playground tools are installed
- playground
- kubectl if you prefer to remove the application with it

$ playground login
Login success

Removing an application

The simplest way to remove an application is using the playground command, execute:

$ playground apps delete <appName>

this command deletes the application and its components and scopes at once.

Anyway, there are two more methods to remove an application depending on how it was deployed and the access to the original sources.

In these cases you need to obtain kubeconfig file to connect to your cluster.

$ playground get-kubeconfig
ASSOCIATED SERVER
https://35.198.177.96

Use this kubeconfig to connect to the cluster and deploy applications:
kubectl --kubeconfig <napptive-kubeconfig> ...

I deployed the app from a directory

If you created the application from a directory, you can use the following shortcut:

$ kubectl --kubeconfig <path_to>/napptive-kubeconfig delete -f /<path_to>/myapp

I want to remove an arbitrary app

To remove an application, identify which are the elements that compose it. The easiest method is to get the information from the application configuration.

$ kubectl --kubeconfig <path_to>/napptive-kubeconfig describe applicationconfigurations.core.oam.dev my-wordpress
...
Spec:
  Components:
    Component Name:  mysql-db
    Parameter Values:
      Name:   password
      Value:  root
      Name:   portNumber
      Value:  3306
    Scopes:
      Scope Ref:
        API Version:  core.oam.dev/v1alpha2
        Kind:         HealthScope
        Name:         wordpress-health
    Component Name:   wordpress
    Parameter Values:
      Name:   dbpass
      Value:  root
      Name:   host
      Value:  mysql-db
    Scopes:
      Scope Ref:
        API Version:  core.oam.dev/v1alpha2
        Kind:         HealthScope
        Name:         wordpress-health
    Traits:
      Trait:
        API Version:  core.oam.dev/v1alpha2
        Kind:         ManualScalerTrait
        Metadata:
          Name:  wordpress-replication
        Spec:
          Replica Count:  1

From the output we can identify that the application is composed by:

mysql-db and wordpress which are the two components of the application.
wordpress-health which is a HealthScope.
wordpress-replication which is a ManualScalerTrait.

To remove the app execute:

$ kubectl --kubeconfig <path_to>/napptive-kubeconfig delete applicationconfigurations.core.oam.dev my-wordpress
applicationconfiguration.core.oam.dev "my-wordpress" deleted
$ kubectl --kubeconfig <path_to>/napptive-kubeconfig delete components.core.oam.dev mysql-db wordpress
component.core.oam.dev "mysql-db" deleted
component.core.oam.dev "wordpress" deleted
$ kubectl --kubeconfig <path_to>/napptive-kubeconfig delete healthscopes.core.oam.dev wordpress-health
healthscope.core.oam.dev "wordpress-health" deleted

Note that the lifecycle of the ManualScalerTrait is linked with the application configuration, so it will be automatically removed.

Removing all applications

In case you want to remove all applications in your cluster, use the following commands:

$ kubectl --kubeconfig <path_to>/napptive-kubeconfig delete --all applicationconfigurations.core.oam.dev
$ kubectl --kubeconfig <path_to>/napptive-kubeconfig delete --all components.core.oam.dev
$ kubectl --kubeconfig <path_to>/napptive-kubeconfig delete --all manualscalertraits.core.oam.dev
$ kubectl --kubeconfig <path_to>/napptive-kubeconfig delete --all healthscopes.core.oam.dev

A note on removal order

Notice that the order in which elements are removed is important as entities are linked together. Please follow the recommended order of removal. If you get an entity stuck in a finalizer, recreate the dependent entity and proceed with the removal process.

What’s next

Check our tutorials on how to deploy predefined applications