With PVC

This tutorial describes how to deploy a VM with an additional 1Gi disk provided by a Persistent Volume Claim (PVC).

Prerequisites

This tutorial assumes the following:

There is a namespace in which the user is able to deploy VirtualMachine resources. In this tutorial, the namespace is my-namespace.
The namespace has access to a VirtualMachineClass. In this tutorial, the class is my-vm-class.
The namespace has access to a VirtualMachineImage (VMI) with Ubuntu 24.04 (Noble Numbat). In this tutorial, the VMI is vmi-cc61318e786a2a31f.
The namespace has access to a StorageClass. In this tutorial, the class is my-storage-class.

Storage Classes

The StorageClass for the VirtualMachine resource applies only to the disks from the VirtualMachineImage from which the VM is deployed. PVCs may specify their own StorageClass, completely different from what the VM uses.

However, for the purpose of simplicity, this tutorial uses the same StorageClass for both the PersistentVolumeClaim and VirtualMachine resources.

Create PVC

The first step is to create a PVC named my-disk that will be used by the VM as additional storage:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-disk
  namespace: my-namespace
spec:
  accessModes:
  - ReadWriteOnce
  volumeMode: Block
  resources:
    requests:
      storage: 1Gi
  storageClassName: my-storage-class

Deploy VM w PVC

The next step is to deploy a VM with the PVC attached as a disk:

apiVersion: vmoperator.vmware.com/v1alpha5
kind: VirtualMachine
metadata:
  name: my-vm-1
  namespace: my-namespace
spec:
  className: my-vm-class
  imageName: vmi-cc61318e786a2a31f # Ubuntu 24.04 Noble Numbat
  storageClass: my-storage-class
  volumes:
  # Attach the PVC named "my-disk" to the VM.
  - name: my-disk
    persistentVolumeClaim:
      claimName: my-disk # Since the image used to deploy the VM has
                         # exactly one disk, this PVC will be attached
                         # as /dev/sdb. Please note, this name is not
                         # guaranteed or deterministic. Any scripts used
                         # to partition/mount disks in production systems
                         # should be more resilient than relying on the
                         # order of volumes in this list or the number of
                         # disks that might already be attached to the VM.
  bootstrap:
    cloudInit:
      cloudConfig:
        users:
        - name: jdoe
          shell: /bin/bash
          sudo: ALL=(ALL) NOPASSWD:ALL
          ssh_authorized_keys:
          - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDSL7uWGj...
        runcmd:
        # Tell Ubuntu to refresh its list of packages.
        - apt-get update  --assume-no

        # Install the parted command used to partition the disk.
        - apt-get install --assume-yes parted

        # Partition the disk, using as much of its space as possible.
        - parted -s /dev/sdb -- mkpart primary ext4 0% 100%

        # Create a filesystem on the disk.
        - mkfs -t ext4 /dev/sdb

        # Create the directory where the disk will be mounted.
        - mkdir -p /mnt/my-data-dir-1

        # Ensure the disk is mounted at boot.
        - echo '/dev/sdb /mnt/my-data-dir-1 ext4 defaults 0 2' >>/etc/fstab

        # Go ahead and mount the disk manually this time.
        - mount -a

Verify PVC on VM

Wait for the VM to be deployed and get an IP address:

kubectl -n my-namespace get vm my-vm-1 -owide -w

SSH into the VM and verify the disk was attached, formatted, and mounted as expected:
```
ssh jdoe@<VM_IP>
```

List the system's block devices:

jdoe@my-vm-1:~$ lsblk
NAME    MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda       8:0    0   10G  0 disk 
├─sda1    8:1    0    9G  0 part /
├─sda14   8:14   0    4M  0 part 
├─sda15   8:15   0  106M  0 part /boot/efi
└─sda16 259:0    0  913M  0 part /boot
sdb       8:16   0    1G  0 disk /mnt/my-data-dir-1

And there it is! The device /dev/sdb is mounted to /mnt/my-data-dir-1!

Finally, create a file at the root of the mounted disk:
```
echo world >/mnt/my-data-dir-1/hello
```

Delete VM

Log out of the VM and go ahead and delete it, but ~~take~~ leave the ~~cannoli~~ PVC:

kubectl -n my-namespace delete vm my-vm-1

Deploy new VM w same PVC

The file written to /mnt/my-data-dir-1/hello in the first VM should still be available on the disk managed by the PVC my-disk. To verify that, deploy a second VM and attach the PVC to it:

apiVersion: vmoperator.vmware.com/v1alpha5
kind: VirtualMachine
metadata:
  name: my-vm-2
  namespace: my-namespace
spec:
  className: my-vm-class
  imageName: vmi-cc61318e786a2a31f # Ubuntu 24.04 Noble Numbat
  storageClass: my-storage-class
  volumes:
  # Attach the PVC named "my-disk" to the VM.
  - name: my-disk
    persistentVolumeClaim:
      claimName: my-disk
  bootstrap:
    cloudInit:
      cloudConfig:
        users:
        - name: jdoe
          shell: /bin/bash
          sudo: ALL=(ALL) NOPASSWD:ALL
          ssh_authorized_keys:
          - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDSL7uWGj...
        runcmd:
        # Create the directory where the disk will be mounted, using a different
        # path than the one from the first VM.
        - mkdir -p /mnt/my-data-dir-2

        #
        # Please note it is not necessary to install the tools
        # to partition the disk this time since the disk was
        # already partitioned and has a file system from the
        # previous VM.
        #

        # Ensure the disk is mounted at boot.
        - echo '/dev/sdb /mnt/my-data-dir-2 ext4 defaults 0 2' >>/etc/fstab

        # Go ahead and mount the disk manually this time.
        - mount -a

Verify PVC on new VM

This section is similar to verifying the PVC on the first VM, but in this case the disk provided by the PVC was not partitioned or formatted prior to being attached, so the only way the disk was mounted successfully is if it is re-used from the previous VM, including the file hello that was written to the root of the disk:

Wait for the VM to be deployed and get an IP address:

kubectl -n my-namespace get vm my-vm-2 -owide -w

SSH into the VM and verify the disk was attached, formatted, and mounted as expected:
```
ssh jdoe@<VM_IP>
```

List the system's block devices:

jdoe@my-vm-2:~$ lsblk
NAME    MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda       8:0    0   10G  0 disk 
├─sda1    8:1    0    9G  0 part /
├─sda14   8:14   0    4M  0 part 
├─sda15   8:15   0  106M  0 part /boot/efi
└─sda16 259:0    0  913M  0 part /boot
sdb       8:16   0    1G  0 disk /mnt/my-data-dir-2

And there it is! The device /dev/sdb is mounted to /mnt/my-data-dir-2!

Finally, verify the file written to the root of the filesystem on /dev/sdb from the first VM is present in the path where the disk is mounted in the new VM:
```
jdoe@my-vm-2:~$ cat /mnt/my-data-dir-2/hello
world
```
Even though the file was originally written to /mnt/my-data-dir-1/hello on the first VM, the same disk is mounted to /mnt/my-data-dir-2 in this new VM, and thus the file, with the expected content, is present at /mnt/my-data-dir-2/hello!