7.13. Cloning virtual machines

Procedure

1. Create a ClusterRole manifest:

   apiVersion: rbac.authorization.k8s.io/v1
   kind: ClusterRole
   metadata:
     name: <datavolume-cloner> 1
   rules:
   - apiGroups: ["cdi.kubevirt.io"]
     resources: ["datavolumes/source"]
     verbs: ["*"]

   1

   Unique name for the ClusterRole.

2. Create the ClusterRole in the cluster:

   $ oc create -f <datavolume-cloner.yaml> 1

   1

   The file name of the ClusterRole manifest created in the previous step.

3. Create a RoleBinding manifest that applies to both the source and destination namespaces and references the ClusterRole created in the previous step.

   apiVersion: rbac.authorization.k8s.io/v1
   kind: RoleBinding
   metadata:
     name: <allow-clone-to-user> 1
     namespace: <Source namespace> 2
   subjects:
   - kind: ServiceAccount
     name: default
     namespace: <Destination namespace> 3
   roleRef:
     kind: ClusterRole
     name: datavolume-cloner 4
     apiGroup: rbac.authorization.k8s.io

   1

   Unique name for the RoleBinding.

   2

   The namespace for the source DataVolume.

   3

   The namespace to which the DataVolume is cloned.

   4

   The name of the ClusterRole created in the previous step.

4. Create the RoleBinding in the cluster:

   $ oc create -f <datavolume-cloner.yaml> 1

   1

   The file name of the RoleBinding manifest created in the previous step.

Procedure

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

2. Create a YAML file for a DataVolume object that specifies the name of the new DataVolume, the name and namespace of the source PVC, and the size of the new DataVolume.

   For example:

   apiVersion: cdi.kubevirt.io/v1alpha1
   kind: DataVolume
   metadata:
     name: <cloner-datavolume> 1
   spec:
     source:
       pvc:
         namespace: "<source-namespace>" 2
         name: "<my-favorite-vm-disk>" 3
     pvc:
       accessModes:
         - ReadWriteOnce
       resources:
         requests:
           storage: <2Gi> 4

   1

   The name of the new DataVolume.

   2

   The namespace where the source PVC exists.

   3

   The name of the source PVC.

   4

   The size of the new DataVolume. You must allocate enough space, or the cloning operation fails. The size must be the same as or larger than the source PVC.

3. Start cloning the PVC by creating the DataVolume:

   $ oc create -f <cloner-datavolume>.yaml

   注意

   DataVolumes prevent a virtual machine from starting before the PVC is prepared, so you can create a virtual machine that references the new DataVolume while the PVC clones.

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 DataVolume called favorite-clone is created from my-favorite-vm-disk.

   For example:

   apiVersion: kubevirt.io/v1alpha3
   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 DataVolume:

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

Procedure

1. Log in as root to the node on which to create the local PV. This procedure uses node01 for its examples.

2. Create a file and populate it with null characters so that it can be used as a block device. The following example creates a file loop10 with a size of 2Gb (20 100Mb blocks):

   $ dd if=/dev/zero of=<loop10> bs=100M count=20

3. Mount the loop10 file as a loop device.

   $ losetup </dev/loop10>d3 <loop10> 1 2

   1

   File path where the loop device is mounted.

   2

   The file created in the previous step to be mounted as the loop device.

4. Create a PersistentVolume configuration that references the mounted loop device.

   kind: PersistentVolume
   apiVersion: v1
   metadata:
     name: <local-block-pv10>
     annotations:
   spec:
     local:
       path: </dev/loop10> 1
     capacity:
       storage: <2Gi>
     volumeMode: Block 2
     storageClassName: local 3
     accessModes:
       - ReadWriteOnce
     persistentVolumeReclaimPolicy: Delete
     nodeAffinity:
       required:
         nodeSelectorTerms:
         - matchExpressions:
           - key: kubernetes.io/hostname
             operator: In
             values:
             - <node01> 4

   1

   The path of the loop device on the node.

   2

   Specifies it is a block PV.

   3

   Optional: Set a StorageClass for the PV. If you omit it, the cluster default is used.

   4

   The node on which the block device was mounted.

5. Create the block PV.

   # oc create -f <local-block-pv10.yaml>1

   1

   The filename of the PersistentVolume created in the previous step.

Procedure

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

2. Create a YAML file for a DataVolume object that specifies the name of the new DataVolume, the name and namespace of the source PVC, volumeMode: Block so that an available block PV is used, and the size of the new DataVolume.

   For example:

   apiVersion: cdi.kubevirt.io/v1alpha1
   kind: DataVolume
   metadata:
     name: <cloner-datavolume> 1
   spec:
     source:
       pvc:
         namespace: "<source-namespace>" 2
         name: "<my-favorite-vm-disk>" 3
     pvc:
       accessModes:
         - ReadWriteOnce
       resources:
         requests:
           storage: <2Gi> 4
       volumeMode: Block 5

   1

   The name of the new DataVolume.

   2

   The namespace where the source PVC exists.

   3

   The name of the source PVC.

   4

   The size of the new DataVolume. You must allocate enough space, or the cloning operation fails. The size must be the same as or larger than the source PVC.

   5

   Specifies that the destination is a block PV

3. Start cloning the PVC by creating the DataVolume:

   $ oc create -f <cloner-datavolume>.yaml

   注意

   DataVolumes prevent a virtual machine from starting before the PVC is prepared, so you can create a virtual machine that references the new DataVolume while the PVC clones.