Persistent Storage

The following components can use persistent storage:

• OpenSearch
• OpenSearch Dashboards
• Prometheus
• Grafana
• Keycloak/MySQL

By default, each Verrazzano installation profile has different storage characteristics. The dev profile uses ephemeral storage only, but in all other profiles, each of the listed components use persistent storage. For more information, see Profile Configurations.

While each profile has its own default persistence settings, in each case you have the option to override the profile defaults to customize your persistence settings.

You can customize the persistence settings for these components through the VerrazzanoSpec, as follows:

• Overriding the persistence settings for all components (Keycloak, Grafana, Prometheus, OpenSearch, and OpenSearch Dashboards) by using the defaultVolumeSource field.
• Overriding the persistence settings for Keycloak by using the volumeSource field on that component’s configuration.

You can set the global defaultVolumeSource and component-level volumeSource fields to one of the following values:

When you want to use a persistentVolumeClaim to override the storage settings for components, you must do the following:

• Create a volumeClaimSpecTemplate which identifies the desired persistence settings.
• Configure a persistentVolumeClaim for the component where the claimName field references the template you created previously.

This lets you create named persistence settings that can be shared across multiple components within a Verrazzano configuration. Note that the existence of a persistence template in the volumeClaimSpecTemplates list does not directly result in the creation of a persistent volume, or affect any component storage settings until it is referenced by either defaultVolumeSource or a specific component’s volumeSource.

Examples

Review the following customizing persistent storage examples:

• Customize persistence globally using defaultVolumeSource
• Customize PersistentVolumeClaim settings for Keycloak using volumeSource
• Use global and local persistence settings together

Customize persistence globally using defaultVolumeSource

If defaultVolumeSource is configured, then that setting will be used for all components that require storage.

For example, the following Verrazzano configuration uses the prod profile, but disables persistent storage for all components.

apiVersion: install.verrazzano.io/v1beta1
kind: Verrazzano
metadata:
  name: no-storage-prod
spec:
  profile: prod
  defaultVolumeSource:
      emptyDir: {}

The following example uses persistentVolumeClaim to override persistence settings globally for a prod profile, to use 100Gi volumes for all components, instead of the default of 50Gi.

apiVersion: install.verrazzano.io/v1beta1
kind: Verrazzano
metadata:
  name: prod-global-override
spec:
  profile: prod
  defaultVolumeSource:
    persistentVolumeClaim:
      claimName: globalOverride
  volumeClaimSpecTemplates:
    - metadata:
        name: globalOverride
      spec:
        resources:
          requests:
            storage: 100Gi

The following example uses a managed-cluster profile but overrides the persistence settings to use ephemeral storage.

apiVersion: install.verrazzano.io/v1beta1
kind: Verrazzano
metadata:
  name: mgdcluster-empty-storage-example
spec:
  profile: managed-cluster
  defaultVolumeSource:
    emptyDir: {}  # Use emphemeral storage for all Components unless overridden

Customize PersistentVolumeClaim settings for Keycloak using volumeSource

The following example Verrazzano configuration enables a 100Gi PersistentVolumeClaim for the MySQL component in Keycloak in a dev profile configuration. This overrides the default of ephemeral storage for Keycloak in that profile, while retaining the default storage settings for other components.

apiVersion: install.verrazzano.io/v1beta1
kind: Verrazzano
metadata:
  name: dev-mysql-storage-example
spec:
  profile: dev
  components:
    keycloak:
      mysql:
        volumeSource:
          persistentVolumeClaim:
            claimName: mysql  # Use the "mysql" PVC template for the MySQL volume configuration
  volumeClaimSpecTemplates:
  - metadata:
      name: mysql      
    spec:
      resources:
        requests:
          storage: 100Gi

Use global and local persistence settings together

The following example uses a dev installation profile, but overrides the profile persistence settings to:

• Use 200Gi volumes for all components by default.
• Use a 100Gi volume for the MySQL instance associated with Keycloak.

apiVersion: install.verrazzano.io/v1beta1
kind: Verrazzano
metadata:
  name: dev-storage-example
spec:
  profile: dev
  defaultVolumeSource:
    persistentVolumeClaim:
      claimName: vmi     # Set storage globally for the metrics stack
  components:
    keycloak:
      mysql:
        volumeSource:
          persistentVolumeClaim:
            claimName: mysql  # Set storage separately for keycloak's MySql instance
  volumeClaimSpecTemplates:
    - metadata:
        name: mysql
      spec:
        resources:
          requests:
            storage: 100Gi
    - metadata:
        name: vmi
      spec:
        resources:
          requests:
            storage: 200Gi