Create and attach disks

This guide shows you how to create boot disks and data disks, attach them to virtual machines, and manage them using the evroc CLI or Kubernetes API.

For information about disks and how they work, see Disks.

Prerequisites

  • Access to an evroc organization and resource group
  • evroc CLI installed and configured, or kubectl configured to access the evroc Kubernetes API

Create a boot disk

A boot disk contains an operating system image that a virtual machine boots from. You must specify a disk image when creating a boot disk.

Using the CLI

Create a boot disk with the evroc compute disk create command:

evroc compute disk create mybootdisk --disk-image=ubuntu.24-04.1 --disk-storage-class=persistent

Using the API

Create a boot disk by applying a YAML configuration:

apiVersion: compute.evroclabs.net/v1alpha1
kind: Disk
metadata:
  name: mybootdisk
spec:
  diskSize:
    amount: 100
    unit: GB
  diskImage:
    diskImageRef:
      name: ubuntu.24-04.1
  diskStorageClass:
    name: persistent

Apply the configuration:

kubectl apply -f bootdisk.yaml

Create a data disk

Data disks provide additional persistent storage for virtual machines. Data disks do not require a disk image, but you must specify the disk size.

Using the CLI

Create a data disk with a specific size:

evroc compute disk create mydisk --disk-storage-class=persistent --disk-size-amount=5 --disk-size-unit=GB

Using the API

Create a data disk by applying a YAML configuration:

apiVersion: compute.evroclabs.net/v1alpha1
kind: Disk
metadata:
  name: mydisk
spec:
  diskSize:
    amount: 5
    unit: GB
  diskStorageClass:
    name: persistent

Apply the configuration:

kubectl apply -f storagedisk.yaml

Attach a disk to an existing VM

You can attach data disks to an existing virtual machine. The VM must be stopped before attaching or detaching disks.

Using the CLI

Add a disk to an existing VM:

evroc compute vm update myvm --append --disk=mydisk

Stop the VM to apply the changes:

evroc compute vm update myvm --running=false

Wait for the VM to stop, then start it again:

evroc compute vm update myvm --running=true

Using the API

Edit the VM specification to add the disk reference to the diskRefs list:

apiVersion: compute.evroclabs.net/v1alpha1
kind: VirtualMachine
metadata:
  name: myvm
spec:
  diskRefs:
  - name: mybootdisk
    bootFrom: true
  - name: mydisk
    bootFrom: false
  # ... other fields

Apply the updated configuration:

kubectl apply -f vm.yaml

Stop and start the VM to attach the disk:

kubectl patch virtualmachine myvm --type=merge -p '{"spec":{"running":false}}'
kubectl patch virtualmachine myvm --type=merge -p '{"spec":{"running":true}}'

Detach a disk from a VM

You can detach data disks from a virtual machine. The VM must be stopped before detaching disks.

Important: Before detaching a disk, remove its entry from /etc/fstab on the VM to prevent boot errors.

Using the CLI

To detach a disk, update the VM with a complete list of disks that excludes the disk you want to detach. For example, if your VM has disks mybootdisk, disk1, and disk2, and you want to detach disk2:

  1. Remove the disk entry from /etc/fstab on the VM

  2. Stop the VM:

    evroc compute vm update myvm --running=false

  3. Update the VM with only the disks you want to keep:

    evroc compute vm update myvm --disk=mybootdisk --boot-from=true --disk=disk1 --boot-from=false

  4. Start the VM:

    evroc compute vm update myvm --running=true

Using the API

Edit the VM specification to remove the disk from the diskRefs list:

kubectl edit virtualmachine myvm

Remove the disk entry from spec.diskRefs, then save and exit. Stop and start the VM to apply the changes:

kubectl patch virtualmachine myvm --type=merge -p '{"spec":{"running":false}}'

Wait for VM to stop.

kubectl patch virtualmachine myvm --type=merge -p '{"spec":{"running":true}}'

List disks

Using the CLI

List all disks in your resource group:

evroc compute disk list

Sample output:

 Name         Ready   Reason   Disk Image
-------      ------- -------- ----------------
 mybootdisk   True             ubuntu.24-04.1
 mydisk       True

Using the API

List disks using kubectl:

kubectl get disks

Sample output:

NAME         READY   REASON   DISKIMAGE
mybootdisk   True             ubuntu.24-04.1
mydisk       True

Delete a disk

Delete disks you no longer need. A disk must not be attached to any virtual machine before you can delete it.

Using the CLI

Delete a disk:

evroc compute disk delete mydisk

Using the API

Delete a disk using kubectl:

kubectl delete disk mydisk

Next steps