Common library Storage¶

This page describes the different ways you can attach storage to charts using the common library.

Types¶

These are the types of storage that are supported in the common library. Of course, other types are possible with the custom type.

Persistent Volume Claim¶

This is probably the most common storage type, therefore it is also the default when no type is specified.

It can be attached in two ways.

Dynamically provisioned¶

Charts can be configured to create the required persistentVolumeClaim manifests on the fly.

Minimal config:

persistence:
  config:
    enabled: true
    type: pvc
    accessMode: ReadWriteOnce
    size: 1Gi

This will create a 1Gi RWO PVC named RELEASE-NAME-config with the default storageClass, which will mount to /config.

Existing claim¶

Charts can be configured to attach to a pre-existing persistentVolumeClaim.

Minimal config:

persistence:
  config:
    enabled: true
    type: pvc
    existingClaim: myAppData

This will mount an existing PVC named myAppData to /config.

Empty Dir¶

Sometimes you need to share some data between containers, or need some scratch space. That is where an emptyDir can come in.

See the Kubernetes docs for more information.

Minimal config:

persistence:
  config:
    enabled: true
    type: emptyDir

This will create an ephemeral emptyDir volume and mount it to /config.

Host path¶

In order to mount a path from the node where the Pod is running you can use a hostPath type persistence item.

This can also be used to mount an attached USB device to a Pod. Note that this will most likely also require setting an elevated securityContext.

See the Kubernetes docs for more information.

Minimal config:

persistence:
  config:
    enabled: true
    type: hostPath
    hostPath: /dev

This will mount the /dev folder from the underlying host to /dev in the container.

configMap¶

In order to mount a configMap to a mount point within the Pod you can use the configMap type persistence item.

Minimal config:

persistence:
  config:
    enabled: true
    type: configMap
    name: mySettings

This will mount the contents of the pre-existing mySettings configMap to /config.

Secret¶

In order to mount a Secret to a mount point within the Pod you can use the secret type persistence item.

Minimal config:

persistence:
  config:
    enabled: true
    type: secret
    name: mySecret

This will mount the contents of the pre-existing mySecret Secret to /config.

NFS Volume¶

To mount an NFS share to your Pod you can either pre-create a persistentVolumeClaim referring to it, or you can specify an inline NFS volume:

Minimal config:

persistence:
  config:
    enabled: true
    type: nfs
    server: 10.10.0.8
    path: /tank/nas/library

This will mount the NFS share /tank/nas/library on server 10.10.0.8 to /config.

Custom¶

When you wish to specify a custom volume, you can use the custom type. This can be used for example to mount configMap or Secret objects.

See the Kubernetes docs for more information.

Permissions¶

Charts do not modify file or folder permissions on volumes out of the box.

This means that you will have to make sure that your storage can be written to by the application.

Multiple subPaths for 1 volume¶

It is possible to mount multiple subPaths from the same volume to the main container. This can be achieved by specifying subPath with a list instead of a string.

Examples:

persistence:
  config:
    enabled: true
    type: custom
    volumeSpec:
      configMap:
        name: myData
    subPath:
      - path: myFirstScript.sh
        mountPath: /data/myFirstScript.sh
      - path: myCertificate.pem
        mountPath: /certs/myCertificate.pem
        readOnly: true

persistence:
  config:
    enabled: true
    type: pvc
    existingClaim: myAppData
    subPath:
      - path: .
        mountPath: /my_media
      - path: Series
        mountPath: /series
      - path: Downloads
        mountPath: /downloads