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Creating virtual machines

You create virtual machines (VMs) by using the OpenShift Container Platform web console or from the command line.

Do not create virtual machines in the default openshift-* namespaces. Instead, create a new namespace or use an existing namespace without the openshift prefix.

Creating a virtual machine by using the web console

You create a virtual machine (VM) from a template or instance type by using the OpenShift Container Platform web console.

Due to differences in storage behavior, some virtual machine templates are incompatible with single-node OpenShift. To ensure compatibility, do not set the evictionStrategy field for templates or virtual machines that use data volumes or storage profiles.

You can expedite VM creation by using templates that have an available boot source. VM templates with a boot source are labeled Available boot source if they do not have a custom label.

Templates without a boot source are labeled Boot source required. You can use these templates if you complete the steps for adding a boot source to the virtual machine.

Creating a virtual machine from a template

You can create a virtual machine (VM) from a template with an available boot source by using the OpenShift Container Platform web console.

Procedure

  1. Navigate to Virtualization → Catalog in the web console.

  2. Click Boot source available to filter templates with boot sources.

    The catalog displays the default templates. Click All Items to view all available templates for your filters.

  3. Click a template tile to view its details.

  4. Click Quick create VirtualMachine to create a VM from the template.

    Optional: Update template or VM parameters:

    1. Click Customize VirtualMachine.

    2. Edit template parameters such as the disk source or VM name.

    3. Click Next.

    4. Edit VM parameters such as network interfaces or disks.

    5. Click Create VirtualMachine.

      The VirtualMachine details page displays the provisioning status.

See storage volume types and storage fields for details about disk sources.

Storage volume types

Table 1. Storage volume types
Type Description

ephemeral

A local copy-on-write (COW) image that uses a network volume as a read-only backing store. The backing volume must be a PersistentVolumeClaim. The ephemeral image is created when the virtual machine starts and stores all writes locally. The ephemeral image is discarded when the virtual machine is stopped, restarted, or deleted. The backing volume (PVC) is not mutated in any way.

persistentVolumeClaim

Attaches an available PV to a virtual machine. Attaching a PV allows for the virtual machine data to persist between sessions.

Importing an existing virtual machine disk into a PVC by using CDI and attaching the PVC to a virtual machine instance is the recommended method for importing existing virtual machines into OpenShift Container Platform. There are some requirements for the disk to be used within a PVC.

dataVolume

Data volumes build on the persistentVolumeClaim disk type by managing the process of preparing the virtual machine disk via an import, clone, or upload operation. VMs that use this volume type are guaranteed not to start until the volume is ready.

Specify type: dataVolume or type: "". If you specify any other value for type, such as persistentVolumeClaim, a warning is displayed, and the virtual machine does not start.

cloudInitNoCloud

Attaches a disk that contains the referenced cloud-init NoCloud data source, providing user data and metadata to the virtual machine. A cloud-init installation is required inside the virtual machine disk.

containerDisk

References an image, such as a virtual machine disk, that is stored in the container image registry. The image is pulled from the registry and attached to the virtual machine as a disk when the virtual machine is launched.

A containerDisk volume is not limited to a single virtual machine and is useful for creating large numbers of virtual machine clones that do not require persistent storage.

Only RAW and QCOW2 formats are supported disk types for the container image registry. QCOW2 is recommended for reduced image size.

A containerDisk volume is ephemeral. It is discarded when the virtual machine is stopped, restarted, or deleted. A containerDisk volume is useful for read-only file systems such as CD-ROMs or for disposable virtual machines.

emptyDisk

Creates an additional sparse QCOW2 disk that is tied to the life-cycle of the virtual machine interface. The data survives guest-initiated reboots in the virtual machine but is discarded when the virtual machine stops or is restarted from the web console. The empty disk is used to store application dependencies and data that otherwise exceeds the limited temporary file system of an ephemeral disk.

The disk capacity size must also be provided.

Storage fields

Field Description

Blank (creates PVC)

Create an empty disk.

Import via URL (creates PVC)

Import content via URL (HTTP or HTTPS endpoint).

Use an existing PVC

Use a PVC that is already available in the cluster.

Clone existing PVC (creates PVC)

Select an existing PVC available in the cluster and clone it.

Import via Registry (creates PVC)

Import content via container registry.

Container (ephemeral)

Upload content from a container located in a registry accessible from the cluster. The container disk should be used only for read-only filesystems such as CD-ROMs or temporary virtual machines.

Name

Name of the disk. The name can contain lowercase letters (a-z), numbers (0-9), hyphens (-), and periods (.), up to a maximum of 253 characters. The first and last characters must be alphanumeric. The name must not contain uppercase letters, spaces, or special characters.

Size

Size of the disk in GiB.

Type

Type of disk. Example: Disk or CD-ROM

Interface

Type of disk device. Supported interfaces are virtIO, SATA, and SCSI.

Storage Class

The storage class that is used to create the disk.
Advanced storage settings

The following advanced storage settings are optional and available for Blank, Import via URL, and Clone existing PVC disks.

If you do not specify these parameters, the system uses the default storage profile values.

Parameter Option Parameter description

Volume Mode

Filesystem

Stores the virtual disk on a file system-based volume.

Block

Stores the virtual disk directly on the block volume. Only use Block if the underlying storage supports it.

Access Mode

ReadWriteOnce (RWO)

Volume can be mounted as read-write by a single node.

ReadWriteMany (RWX)

Volume can be mounted as read-write by many nodes at one time.

This mode is required for live migration.

Creating a virtual machine from an instance type

You create a virtual machine (VM) from an instance type by using the OpenShift Container Platform web console.

Creating a virtual machine from an instance type is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.
Procedure

  1. In the web console, navigate to Virtualization → Catalog and click the InstanceTypes tab.

  2. Select a bootable volume.

    The volume table only lists volumes in the openshift-virtualization-os-images namespace that have the instancetype.kubevirt.io/default-preference label.

  3. Click an instance type tile and select the configuration appropriate for your workload.

  4. Optional: Expand Advanced settings to add a static public SSH key to the VM.

  5. Click Create VirtualMachine.

After the VM is created, you can monitor the status on the VirtualMachine details page.

Creating a virtual machine by using the command line

You can create a virtual machine (VM) by using the command line.

Procedure

  1. Edit the VirtualMachine manifest for your VM. The following example configures a Red Hat Enterprise Linux (RHEL) VM:

    Example manifest for a RHEL VM 
    apiVersion: kubevirt.io/v1
kind: VirtualMachine
metadata:
  labels:
    app: <vm_name> (1)
  name: <vm_name>
spec:
  dataVolumeTemplates:
  - apiVersion: cdi.kubevirt.io/v1beta1
    kind: DataVolume
    metadata:
      name: <vm_name>
    spec:
      sourceRef:
        kind: DataSource
        name: rhel9
        namespace: openshift-virtualization-os-images
      storage:
        resources:
          requests:
            storage: 30Gi
  running: false
  template:
    metadata:
      labels:
        kubevirt.io/domain: <vm_name>
    spec:
      domain:
        cpu:
          cores: 1
          sockets: 2
          threads: 1
        devices:
          disks:
          - disk:
              bus: virtio
            name: rootdisk
          - disk:
              bus: virtio
            name: cloudinitdisk
          interfaces:
          - masquerade: {}
            name: default
          rng: {}
        features:
          smm:
            enabled: true
        firmware:
          bootloader:
            efi: {}
        resources:
          requests:
            memory: 8Gi
      evictionStrategy: LiveMigrate
      networks:
      - name: default
        pod: {}
      volumes:
      - dataVolume:
          name: <vm_name>
        name: rootdisk
      - cloudInitNoCloud:
          userData: |-
            #cloud-config
            user: cloud-user
            password: '<password>' (2)
            chpasswd: { expire: False }
        name: cloudinitdisk
    1 Specify the name of the virtual machine.
    2 Specify the password for cloud-user.

  2. Create a virtual machine by using the manifest file:

    $ oc create -f <vm_manifest_file>.yaml

  3. Optional: Start the virtual machine:

    $ virtctl start <vm_name>

Additional resources