OpenShift PVC

OpenShift PVC resources represent the PersistentVolumeClaims of an OpenShift cluster. The OpenShift integration backs up and restores their contents with two protocols:

• openshift+csi takes a CSI VolumeSnapshot of the PVC and reads the volume from it, so the volume is captured at a single point in time. It is available for backup only.
• openshift+pvc reads the live volume directly, and is the only protocol used to restore a PVC, whichever protocol backed it up. A restore writes into a new or an existing PVC.

Both protocols move the data through a data mover pod started in the namespace of the PVC and deleted when the operation ends. Snapshots taken for a backup are deleted as well. The pod runs as the default ServiceAccount of the namespace and pulls its image from ghcr.io/plakarkorp/kubelet by default. A cluster that cannot reach ghcr.io needs the image from another registry, set with Kubelet Image. See disconnected clusters for how to mirror it.

The kubeconfig used by the app must grant the permissions required by the protocol. The roles in the Kubernetes RBAC guide apply to OpenShift as well. Both protocols use the PVC backup and restore role. When Plakar runs outside the cluster, they also need the port forwarding role.

Inventory Management

Managed inventories discover PersistentVolumeClaims automatically once the OpenShift inventory is connected to a cluster.

Backup flow

flowchart TD
  subgraph OpenShift["OpenShift Cluster"]
    PVC["PersistentVolumeClaim"]
    Snap["VolumeSnapshot
(openshift+csi)"]
    Mover["Data mover pod"]
  end

  subgraph Plakar["Plakar Control Plane"]
    Source["OpenShift PVC
Source app"]
    Backup["Backup process
Encrypt & deduplicate"]
  end

  Store["Kloset Store"]

  PVC --> Snap
  PVC --> Mover
  Snap --> Mover
  Mover -->|"reads volume data"| Source
  Source --> Backup
  Backup --> Store

Restore flow

flowchart TD
  Store["Kloset Store"]

  subgraph Plakar["Plakar Control Plane"]
    Destination["OpenShift PVC
Destination app"]
    Restore["Restore process"]
  end

  subgraph OpenShift["OpenShift Cluster"]
    Mover["Data mover pod"]
    PVC["New or existing PVC"]
  end

  Store --> Restore
  Destination --> Restore
  Restore -->|"writes via"| Mover
  Mover --> PVC

Shared Configuration

The following settings are available when configuring both source and destination apps.

• Kubeconfig: Paste the contents of a kubeconfig. Leave it empty when Plakar Control Plane runs inside the cluster to use the in-cluster credentials. The kubeconfig can also be loaded from a secret provider.
• Kubelet Image: Optional. The image of the data mover pod. Set it to pull the image from a registry the cluster can reach.
• Node Affinity: Optional. Node affinity of the data mover pod, as the YAML or JSON body of a pod’s spec.affinity.nodeAffinity.

Source Configuration

The following setting is only available when configuring source apps with the openshift+csi protocol.

• Volume Snapshot Class: Required. The VolumeSnapshotClass used to snapshot the PVC.