Apps in SCALE rely on several kinds of storage for core data:

• Persistent Volumes (PVC), a specific volume which Kubernetes will not delete (i.e. persist) through upgrades, restarts, and rollbacks of your app/chart.
• Hostpaths (hostpath), a path (/mnt/tank/pool/folder) to a data volume, typically a dataset within a pool on your SCALE installation, or a mounted folder to network attached storage.
• You can use a folder mapped to the container or memory (emptyDir).
• You can directly link an NFS share (NFS Share) to your app storage.

You can choose during app installation to use a PVC to store all of your app's data, or manually assign a hostpath.

Note: We only provide support for apps using PVC for core app storage, often named "config", but you can always add additional hostpaths for other storage, such as your media.

Adding additional app storage

Even if an app doesn't let you specify a hostpath in its chart config, the TrueCharts config lets you add additional app storage through hostpaths which are linked to a local path on the app (e.g linking /mnt/tank/pool/folder to /media/folder). This will allow the path on your SCALE installation to be available from your app, assuming permissions are correctly configured.

From your SCALE App's configuration (during or after installation):

1. Scroll down to Storage and Persistence
2. Under Additional App Storage, click Add
3. Check the box next to Automatic Permissions if you'd like the app to automatically configure permissions to the UID of the container (default: 568)
4. Specify the type of storage you'd like to add (typically a hostpath)
5. (For hostpaths) Specify the path on your SCALE installation you'd like to mount to the container (e.g. /mnt/tank/pool/folder)
6. (For hostpaths) Specify the path on you App you'd like to link to the hostpath (e.g. /media/folder)
7. Click Save to re-create your App with the specified additional app storage.

Permissions

Permissions apply for app storage and are based on the app's fsGroup which you can configure during app installation. By default most apps will set this to the apps group (568).

Apps also have a Automatic Permissions option for app storage and additional app storage. If you enable automatic permissions, the app will attempt to chown the hostpath and all subfolders within the hostpath during deployment. Note: This may not work for large volumes.