Configuring Persistent Storage

This section describes the changes required to configure persistent storage.

For further information see: Kubernetes persistent volumes.

Important: If you are using the HostPath persistent volume then you must ensure the correct permissions and ownership. If you are using the security context the ownership must match the UID of the user and the GID of the group specified in the security context. The file permissions must allow a write to the HostPath volume. Please see: Kubernetes storage volumes HostPath for further details.

Enable Persistent Storage

In the 'values.yaml' file ensure the following parameter is set:

enablePersistentStorage: true

This is the default value to prevent loss of data.
Alert will not startup correctly if this is set to 'true' and persistent volumes are not configured.
If this is set to 'false' when the deployment is uninstalled, all data will be lost.

With Storage Claims

This section defines configuration using Persistent Volume Claims. Claims can be optionally used rather than just a persistent volume. You must have a claim created for the 'alert' service regardless of an on-premise or external database. For the on-premise database deployment a second Persistent Volume Claim must be created to store the database data.

Alert Volume Claim Configuration

A persistent volume must be created first if a dynamic provisioner is not being used.
A persistent volume claim must be created in the same namespace as the Alert deployment and bound to the persistent volume for Alert.
Configure Alert to use the volume claim.
```
alert:
  persistentVolumeClaimName: "<ALERT_CLAIM_NAME>"
```
Replace <ALERT_CLAIM_NAME> with the name of the persistent volume claim for Alert data.
An optional storage class with the persistent volume claim requires the addition of the storage class name.
```
alert:
  persistentVolumeClaimName: "<ALERT_CLAIM_NAME>"
  storageClassName: "<STORAGE_CLASS_NAME>"  
```
Replace <STORAGE_CLASS_NAME> with the name of the storage class in the persistent volume claim.
```
alert:
    persistentVolumeClaimName: "alert-pvc"
    storageClassName: "myStorageClass"
```

Using On-Premise Database

A persistent volume must be created first for the Postgres database if a dynamic provisioner is not being used.
A persistent volume claim must be created in the same namespace as the Alert deployment for Postgres and bound to the persistent volume for Postgres.
Configure Postgres to use the volume claim.
```
postgres:
  persistentVolumeClaimName: "<POSTGRES_CLAIM_NAME>"
```
Replace <POSTGRES_CLAIM_NAME> with the name of the persistent volume claim for Postgres data
An optional storage class with the persistent volume claim requires the addition of the storage class name.
```
postgres:
  persistentVolumeClaimName: "<POSTGRES_CLAIM_NAME>"
  storageClassName: "<STORAGE_CLASS_NAME>"  
```
Replace <STORAGE_CLASS_NAME> with the name of the storage class in the persistent volume claim
```
postgres:
  persistentVolumeClaimName: "postgres-pvc"
  storageClassName: "myStorageClass"
```

Without Storage Claims

This section defines configuration using Persistent Volume. Claims will automatically be created and bound to the volumes defined. You must have a Persistent Volume created for the 'alert' service regardless of an on-premise or external database. For the on-premise database deployment a second Persistent Volume must be created to store the database data.

Alert Volume Configuration

A persistent volume must be created first if a dynamic provisioner not being used
Configure Alert to use the volume name
```
alert:
  volumeName: "<ALERT_VOLUME_NAME>"
```
Replace <ALERT_VOLUME_NAME> with the name of the persistent volume for Alert data
An optional storage class with the persistent volume requires the addition of the storage class name
```
alert:
  volumeName: "<ALERT_VOLUME_NAME>"
  storageClassName: "<STORAGE_CLASS_NAME>"  
```
Replace <STORAGE_CLASS_NAME> with the name of the storage class in the persistent volume claim.

Define the claim size by default it is 5GB.

alert:
  claimSize: "5Gi"

alert:
  claimSize: "5Gi"
  storageClassName: "myStorageClass"
  volumeName: "alert-volume"

A claim will be created with the release name for example 'myalert-pvc' please verify the claim bound to the volume.
```
$ kubectl -n <ALERT_NAMESPACE> get pvc
```

Using On-Premise Database

A persistent volume must be created first for the Postgres database if a dynamic provisioner not being used.
Configure Alert to use the volume name.
```
postgres:
  volumeName: "<POSTGRES_VOLUME_NAME>"
```
Replace <POSTGRES_VOLUME_NAME> with the name of the persistent volume for Postgres data.
An optional storage class with the persistent volume requires the addition of the storage class name.
```
postgres:
  volumeName: "<POSTGRES_VOLUME_NAME>"
  storageClassName: "<STORAGE_CLASS_NAME>"  
```
Replace <STORAGE_CLASS_NAME> with the name of the storage class in the persistent volume claim

Define the claim size by default it is 5GB

postgres:
  claimSize: "5Gi"

postgres:
  claimSize: "5Gi"
  storageClassName: "myStorageClass"
  volumeName: "postgres-volume"

A claim will be created with the release name for example 'myalert-postgres' please verify the claim bound to the volume
```
$ kubectl -n <ALERT_NAMESPACE> get pvc
```