Cloning a virtual machine by using a data volume template

• Prerequisites
• About data volumes
• Creating a new virtual machine from a cloned persistent volume claim by using a data volume template
• Template: Data volume virtual machine configuration file
• CDI supported operations matrix

You can create a new virtual machine by cloning the persistent volume claim (PVC) of an existing VM. By including a dataVolumeTemplate in your virtual machine configuration file, you create a new data volume from the original PVC.

Prerequisites

• Users need additional permissions to clone the PVC of a virtual machine disk into another namespace.

About data volumes

DataVolume objects are custom resources that are provided by the Containerized Data Importer (CDI) project. Data volumes orchestrate import, clone, and upload operations that are associated with an underlying persistent volume claim (PVC). Data volumes are integrated with OKD Virtualization, and they prevent a virtual machine from being started before the PVC has been prepared.

Creating a new virtual machine from a cloned persistent volume claim by using a data volume template

You can create a virtual machine that clones the persistent volume claim (PVC) of an existing virtual machine into a data volume. Reference a dataVolumeTemplate in the virtual machine manifest and the source PVC is cloned to a data volume, which is then automatically used for the creation of the virtual machine.

Prerequisites

• Determine the PVC of an existing virtual machine disk to use. You must power down the virtual machine that is associated with the PVC before you can clone it.

• Install the OpenShift CLI (oc).

Procedure

1. Examine the virtual machine you want to clone to identify the name and namespace of the associated PVC.

2. Create a YAML file for a VirtualMachine object. The following virtual machine example clones my-favorite-vm-disk, which is located in the source-namespace namespace. The 2Gi data volume called favorite-clone is created from my-favorite-vm-disk.

   For example:

   apiVersion: kubevirt.io/v1
   kind: VirtualMachine
   metadata:
     labels:
       kubevirt.io/vm: vm-dv-clone
     name: vm-dv-clone (1)
   spec:
     running: false
     template:
       metadata:
         labels:
           kubevirt.io/vm: vm-dv-clone
       spec:
         domain:
           devices:
             disks:
             - disk:
                 bus: virtio
               name: root-disk
           resources:
             requests:
               memory: 64M
         volumes:
         - dataVolume:
             name: favorite-clone
           name: root-disk
     dataVolumeTemplates:
     - metadata:
         name: favorite-clone
       spec:
         pvc:
           accessModes:
           - ReadWriteOnce
           resources:
             requests:
               storage: 2Gi
         source:
           pvc:
             namespace: "source-namespace"
             name: "my-favorite-vm-disk"

   1	The virtual machine to create.

3. Create the virtual machine with the PVC-cloned data volume:

   $ oc create -f <vm-clone-datavolumetemplate>.yaml

Template: Data volume virtual machine configuration file

example-dv-vm.yaml

apiVersion: kubevirt.io/v1
kind: VirtualMachine
metadata:
  labels:
    kubevirt.io/vm: example-vm
  name: example-vm
spec:
  dataVolumeTemplates:
  - metadata:
      name: example-dv
    spec:
      pvc:
        accessModes:
        - ReadWriteOnce
        resources:
          requests:
            storage: 1G
      source:
          http:
             url: "" (1)
  running: false
  template:
    metadata:
      labels:
        kubevirt.io/vm: example-vm
    spec:
      domain:
        cpu:
          cores: 1
        devices:
          disks:
          - disk:
              bus: virtio
            name: example-dv-disk
        machine:
          type: q35
        resources:
          requests:
            memory: 1G
      terminationGracePeriodSeconds: 0
      volumes:
      - dataVolume:
          name: example-dv
        name: example-dv-disk

CDI supported operations matrix

This matrix shows the supported CDI operations for content types against endpoints, and which of these operations requires scratch space.

✓ Supported operation

□ Unsupported operation

* Requires scratch space

** Requires scratch space if a custom certificate authority is required