Block Storage

Kube-DC provides persistent block storage through two Kubernetes-native mechanisms: DataVolumes for virtual machines and PersistentVolumeClaims (PVCs) for containers. Both are managed through the Volumes view in the dashboard or via kubectl.

Volumes Dashboard

The Volumes view shows all persistent storage in your project. Volumes are organized by Storage Class in the left sidebar. Each volume shows its name, attachment status, capacity, storage class, type (DataVolume or PVC), age, and which VM or pod it is attached to.

Click on any volume to expand its details:

The detail panel shows:

Volume Information — Name, type, capacity, and storage class
Status — Attachment status and which VM/pod the volume is attached to
Actions — Detach, Clone, or View YAML

Understanding Volume Types

DataVolumes (Virtual Machines)

A DataVolume is a KubeVirt resource provided by the Containerized Data Importer (CDI). It automates creating a PVC and populating it with data from a source — typically an OS image for a VM root disk.

When you create a VM, the platform automatically creates a DataVolume as the root disk. DataVolumes can import data from:

HTTP/HTTPS URL — Download a cloud image (e.g., Debian, Ubuntu)
Container Registry — Pull a disk image from a container registry
Blank — Create an empty disk for additional storage

Example: VM root disk DataVolume

apiVersion: cdi.kubevirt.io/v1beta1
kind: DataVolume
metadata:
  name: debian-root
  namespace: shalb-jumbolot
spec:
  source:
    http:
      url: https://cloud.debian.org/images/cloud/bookworm/latest/debian-12-generic-amd64.qcow2
  pvc:
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 20G
    storageClassName: local-path

Once the import completes (Phase: Succeeded), the DataVolume is ready and can be attached to a VM.

Example: Blank data disk

apiVersion: cdi.kubevirt.io/v1beta1
kind: DataVolume
metadata:
  name: data-disk
  namespace: shalb-jumbolot
spec:
  source:
    blank: {}
  pvc:
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 50G
    storageClassName: local-path

PersistentVolumeClaims (Containers)

A PVC is a standard Kubernetes resource for requesting persistent storage. Use PVCs when your containerized workloads (Deployments, StatefulSets, Pods) need data that persists across restarts.

Example: PVC for a database

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres-data
  namespace: shalb-jumbolot
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
  storageClassName: local-path

Mount it in a Pod:

apiVersion: v1
kind: Pod
metadata:
  name: postgres
  namespace: shalb-jumbolot
spec:
  containers:
    - name: postgres
      image: postgres:16
      volumeMounts:
        - name: data
          mountPath: /var/lib/postgresql/data
  volumes:
    - name: data
      persistentVolumeClaim:
        claimName: postgres-data

DataVolume vs PVC — When to Use Which

Feature	DataVolume	PVC
Primary use	VM root and data disks	Container storage
Data import	Automatic (HTTP, registry, blank)	Manual (empty on creation)
Created by	VM provisioning or manually	Directly by user
Backed by	Creates a PVC internally	Directly binds to a PersistentVolume
Visible in UI	Yes (Volumes tab, type: DataVolume)	Yes (Volumes tab, type: PVC)

Storage Classes

A StorageClass defines what type of storage backs your volumes. The available storage classes depend on the infrastructure provider.

Current Default: `local-path`

$ kubectl get storageclass
NAME                   PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE
local-path (default)   rancher.io/local-path   Delete          WaitForFirstConsumer

The local-path storage class provisions storage on the local disk of the node where the workload runs. Key characteristics:

Fast — Direct local disk I/O, no network overhead
Node-bound — Data is stored on a specific node; the workload must run on the same node
Delete reclaim policy — When a PVC is deleted, the underlying data is removed

Provider-Dependent Storage Classes

Storage classes vary by infrastructure provider. Some platforms may offer:

Network-attached storage (e.g., Ceph RBD, Longhorn) — Data accessible from any node, supports live migration
SSD-backed classes — Higher IOPS for database workloads
HDD-backed classes — Cost-effective for large datasets

Check your available storage classes with kubectl get storageclass. Always specify the storageClassName in your PVC or DataVolume to ensure you get the expected storage type.

Creating Volumes

Via Dashboard

Navigate to your project → Volumes tab
Click + Create Volume
Choose the volume type, size, and storage class
Click Create

Via kubectl

Create a DataVolume (for VMs):

kubectl apply -f - <<EOF
apiVersion: cdi.kubevirt.io/v1beta1
kind: DataVolume
metadata:
  name: my-data-disk
  namespace: shalb-jumbolot
spec:
  source:
    blank: {}
  pvc:
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 30G
    storageClassName: local-path
EOF

Create a PVC (for containers):

kubectl apply -f - <<EOF
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
  namespace: shalb-jumbolot
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
  storageClassName: local-path
EOF

Managing Volumes

Check Volume Status

# List all PVCs
kubectl get pvc -n shalb-jumbolot

# List all DataVolumes
kubectl get datavolumes -n shalb-jumbolot

# Get volume details
kubectl describe pvc debian-root -n shalb-jumbolot

Clone a Volume

From the Volumes dashboard, expand a volume and click Clone to create an identical copy. This is useful for creating backups or testing with production data.

Detach a Volume

Click Detach to disconnect a volume from its VM or pod without deleting the data. The volume can be reattached later.

Delete a Volume

# Delete a DataVolume (also deletes the underlying PVC)
kubectl delete datavolume my-data-disk -n shalb-jumbolot

# Delete a PVC directly
kubectl delete pvc my-pvc -n shalb-jumbolot

warning

Deleting a volume permanently removes the data. With the Delete reclaim policy (default), there is no recovery after deletion.

Quick Reference

Action	Command
List PVCs	`kubectl get pvc -n my-project`
List DataVolumes	`kubectl get datavolumes -n my-project`
List StorageClasses	`kubectl get storageclass`
Describe volume	`kubectl describe pvc <name> -n my-project`
Delete DataVolume	`kubectl delete datavolume <name> -n my-project`
Delete PVC	`kubectl delete pvc <name> -n my-project`

Next Steps

Object Storage — S3-compatible storage for files and backups
Backups & Snapshots

Volumes Dashboard​

Understanding Volume Types​

DataVolumes (Virtual Machines)​

PersistentVolumeClaims (Containers)​

DataVolume vs PVC — When to Use Which​

Storage Classes​

Current Default: local-path​

Creating Volumes​

Via Dashboard​

Via kubectl​

Managing Volumes​

Check Volume Status​

Clone a Volume​

Detach a Volume​

Delete a Volume​

Quick Reference​

Next Steps​