Cloneable Virtual Machines

To create a cloneable VM, you will need to create a VMDisk and a VMInstance. This guide uses an ubuntu base image as an example.

1. Create VMDisk

   apiVersion: apps.cozystack.io/v1alpha1
   kind: VMDisk
   metadata:
     name: ubuntu-source
     namespace: tenant-root
   spec:
     optical: false
     source:
       http:
         url: https://cloud-images.ubuntu.com/noble/current/noble-server-cloudimg-amd64.img
     storage: 20Gi
     storageClass: replicated
   

   Since expanding a disk can be complicated, we recommend creating it with extra space to accommodate future growth.

2. Create VMInstance

   Since the VirtualMachine custom resource does not provide an easy way to work with multiple disks, use VMInstance instead.

   Create VMInstance using the following template:

   apiVersion: apps.cozystack.io/v1alpha1
   kind: VMInstance
   metadata:
     name: sourcevm
     namespace: tenant-root
   spec:
     externalMethod: PortList
     disks:
       - name: ubuntu-source
     externalPorts:
       - 22
     instanceProfile: ubuntu
     instanceType: ""
     running: true
     sshKeys:
       - <paste your ssh public key here>
     external: true
     resources:
       cpu: "2"
       memory: 4Gi
   

   When VM is created, it will get load balancer external IP address. You can get it using:

   kubectl get svc -n tenant-root vm-instance-sourcevm
   

3. SSH into VM

   Now you can SSH into VM using the external IP address. Default user for ubuntu base image is ubuntu.

   ssh ubuntu@<external IP>
   

   Configure the virtual machine before cloning.

4. Delete VMInstance

   Data on the disk will be preserved.

   kubectl delete vminstance -n tenant-root sourcevm
   

5. Create disk image

   apiVersion: cdi.kubevirt.io/v1beta1
   kind: DataVolume
   metadata:
     name: "vm-image-sourcevm" # prefix vm-image is necessary
     namespace: cozy-public # do not change
     annotations:
       cdi.kubevirt.io/storage.bind.immediate.requested: "true"
   spec:
     source:
       pvc:
         name: vm-disk-ubuntu-source
         namespace: tenant-root
     storage:
       resources:
         requests:
           storage: 20Gi
       storageClassName: replicated
   

   It will take some time to complete. Wait before continuing. You can check the progress using:

   kubectl get datavolume -n cozy-public vm-image-sourcevm
   

   Example output when ready:

   NAME                PHASE       PROGRESS   RESTARTS   AGE
   vm-image-sourcevm   Succeeded   100.0%                7m32s
   

6. Create VMDisk from cloned image

   apiVersion: apps.cozystack.io/v1alpha1
   kind: VMDisk
   metadata:
     name: ubuntu-cloned-1
     namespace: tenant-root
   spec:
     optical: false
     source:
       image:
         name: sourcevm # image name without prefix
     storage: 20Gi # size greater or equal to the disk image size
     storageClass: replicated
   

7. Create VMInstance from cloned disk

   apiVersion: apps.cozystack.io/v1alpha1
   kind: VMInstance
   metadata:
     name: cloned-vm
     namespace: tenant-root
   spec:
     external: true
     externalMethod: PortList
     cloudInit: "hostname: my-cloned-vm"
     cloudInitSeed: "1"
     disks:
       - name: ubuntu-cloned-1
     externalPorts:
       - 22
     instanceProfile: ubuntu
     running: true
   

   To ensure the cloned VM’s network functions correctly, you must override its hostname via .spec.cloudInit and provide a unique .spec.cloudInitSeed to prevent conflicts with the source VM.