Kubernetes PVC

The Kubernetes integration allows Plakar Control Plane to back up and restore the contents of Kubernetes PersistentVolumeClaims. Kubernetes integration supports multiple protocols for backup, either via the CSI driver snapshot feature (preferred) or by reading the volume directly.

The k8s+csi protocol backs up a PVC by creating a VolumeSnapshot through the cluster’s CSI driver, then reading the snapshot’s data through a helper pod. It is the preferred backup method when the cluster’s storage class supports the VolumeSnapshot API, since the snapshot captures a consistent point-in-time copy of the volume without needing to quiesce the workload manually.

This protocol is available for backup only. Restoring a PVC always uses the k8s+pvc protocol, described below. Because k8s+pvc is the only protocol Control Plane can use to restore PVC data, it is selected automatically and the protocol selector is not shown during restore.

flowchart TD
  subgraph K8s["Kubernetes Cluster"]
    PVC["PersistentVolumeClaim"]
    Snap["VolumeSnapshot"]
    Helper["Helper pod"]
  end

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

  Store["Kloset Store"]

  Source -->|"creates"| Snap
  PVC --> Snap
  Snap --> Helper
  Helper -->|"reads snapshot data"| Source
  Source --> Backup
  Backup --> Store

The following settings are available when configuring a source app using the k8s+csi protocol.

• Kubeconfig: Required. Upload a kube config YAML file or paste its contents directly.
• Kubelet Image: The container image used for the helper pod. Leave this unset. It exists only so that Plakar support can supply a replacement image while diagnosing a problem, and a working deployment never needs it.
• Volume Snapshot Class: Required. The name of the VolumeSnapshotClass to use when creating the CSI snapshot.

The k8s+pvc protocol reads a PVC’s contents directly, without going through a CSI snapshot. It supports both backup and restore, and is the only protocol available for restoring PVC data, regardless of which protocol was used to back it up.

Use this protocol for backup when the cluster’s storage class has no VolumeSnapshot support.

flowchart TD
  subgraph K8s["Kubernetes Cluster"]
    PVC["PersistentVolumeClaim"]
    Helper["Helper pod"]
  end

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

  Store["Kloset Store"]

  Source -->|"mounts via"| Helper
  PVC --> Helper
  Helper -->|"reads volume data"| Source
  Source --> Backup
  Backup --> Store

flowchart TD
  Store["Kloset Store"]

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

  subgraph K8s["Kubernetes Cluster"]
    Helper["Helper pod"]
    PVC["Restored 
 PersistentVolumeClaim"]
  end

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

The following settings are available when configuring both source and destination apps using the k8s+pvc protocol.

• Kubeconfig: Required. Upload a kube config YAML file or paste its contents directly.
• Kubelet Image: The container image used for the helper pod. Leave this unset. It exists only so that Plakar support can supply a replacement image while diagnosing a problem, and a working deployment never needs it.