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Creating virtual machines - Virtual machines | OpenShift Virtualization | OpenShift Container Platform 4.5
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Creating virtual machines

Use one of these procedures to create a virtual machine:

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

Running the virtual machine wizard to create a virtual machine

The web console features an interactive wizard that guides you through General, Networking, Storage, Advanced, and Review steps to simplify the process of creating virtual machines. All required fields are marked by a *. When the required fields are completed, you can review and create your virtual machine.

Network Interface Cards (NICs) and storage disks can be created and attached to virtual machines after they have been created.

Bootable Disk

If either URL or Container are selected as the Source in the General step, a rootdisk disk is created and attached to the virtual machine as the Bootable Disk. You can modify the rootdisk but you cannot remove it.

A Bootable Disk is not required for virtual machines provisioned from a PXE source if there are no disks attached to the virtual machine. If one or more disks are attached to the virtual machine, you must select one as the Bootable Disk.

Prerequisites

  • When you create your virtual machine using the wizard, your virtual machine’s storage medium must support Read-Write-Many (RWX) PVCs.

Procedure

  1. Click Workloads → Virtualization from the side menu.

  2. Click the Virtual Machines tab.

  3. Click Create Virtual Machine and select New with Wizard.

  4. Fill in all required fields in the General step. Selecting a Template automatically fills in these fields.

  5. Click Next to progress to the Networking step. A nic0 NIC is attached by default.

    1. Optional: Click Add Network Interface to create additional NICs.

    2. Optional: You can remove any or all NICs by clicking the Options menu kebab and selecting Delete. A virtual machine does not need a NIC attached to be created. NICs can be created after the virtual machine has been created.

  6. Click Next to progress to the Storage screen.

    1. Optional: Click Add Disk to create additional disks. These disks can be removed by clicking the Options menu kebab and selecting Delete.

    2. Optional: Click the Options menu kebab to edit the disk and save your changes.

  7. Click Review and Create. The Results screen displays the JSON configuration file for the virtual machine.

The virtual machine is listed in the Virtual Machines tab.

Refer to the virtual machine wizard fields section when running the web console wizard.

Virtual machine wizard fields

Name Parameter Description

Template

Template from which to create the virtual machine. Selecting a template will automatically complete other fields.

Source

PXE

Provision virtual machine from PXE menu. Requires a PXE-capable NIC in the cluster.

URL

Provision virtual machine from an image available from an HTTP or S3 endpoint.

Container

Provision virtual machine from a bootable operating system container located in a registry accessible from the cluster. Example: kubevirt/cirros-registry-disk-demo.

Disk

Provision virtual machine from a disk.

Operating System

The primary operating system that is selected for the virtual machine.

Flavor

small, medium, large, tiny, Custom

Presets that determine the amount of CPU and memory allocated to the virtual machine. The presets displayed for Flavor are determined by the operating system.

Memory

Size in GiB of the memory allocated to the virtual machine.

CPUs

The amount of CPU allocated to the virtual machine.

Workload Profile

High Performance

A virtual machine configuration that is optimized for high-performance workloads.

Server

A profile optimized to run server workloads.

Desktop

A virtual machine configuration for use on a desktop.

Name

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

Description

Optional description field.

Start virtual machine on creation

Select to automatically start the virtual machine upon creation.

Cloud-init fields

Name Description

Hostname

Sets a specific host name for the virtual machine.

Authenticated SSH Keys

The user’s public key that is copied to ~/.ssh/authorized_keys on the virtual machine.

Custom script

Replaces other options with a field in which you paste a custom cloud-init script.

CD-ROM fields

Source Description

Container

Specify the container path. For example: kubevirt/fedora-registry-disk: latest.

URL

Specify the URL path and size in GiB. Then, select the storage class for this URL from the drop-down list.

Attach Disk

Select the virtual machine disk that you want to attach.

Networking fields

Name Description

Name

Name for the Network Interface Card.

Model

Indicates the model of the Network Interface Card. Supported values are e1000, e1000e, ne2k_pci, pcnet, rtl8139, and virtIO.

Network

List of available NetworkAttachmentDefinition objects.

Type

List of available binding methods. For the default Pod network, masquerade is the only recommended binding method. For secondary networks, use the bridge binding method. The masquerade method is not supported for non-default networks.

MAC Address

MAC address for the Network Interface Card. If a MAC address is not specified, an ephemeral address is generated for the session.

Storage fields

Name Description

Source

Select a blank disk for the virtual machine or choose from the options available: URL, Container, Attach Cloned Disk, or Attach Disk. To select an existing disk and attach it to the virtual machine, choose Attach Cloned Disk or Attach Disk from a list of available PersistentVolumeClaims (PVCs).

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 (GiB)

Size, in GiB, of the disk.

Interface

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

Storage Class

The StorageClass that is used to create the disk.

Advanced → Volume Mode

Defines whether the persistent volume uses a formatted file system or raw block state. Default is Filesystem.

Advanced → Access Mode

Access mode of the persistent volume. Supported access modes are Single User (RWO), Shared Access (RWX), and Read Only (ROX).

Advanced storage settings

The following advanced storage settings are available for Blank, Import via URL, and Clone existing PVC disks. These parameters are optional. If you do not specify these parameters, the system uses the default values from the kubevirt-storage-class-defaults config map.

Name Parameter Description

Volume Mode

Filesystem

Stores the virtual disk on a filesystem-based volume.

Block

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

Access Mode

Single User (RWO)

The disk can be mounted as read/write by a single node.

Shared Access (RWX)

The disk can be mounted as read/write by many nodes.

This is required for some features, such as live migration of virtual machines between nodes.

Read Only (ROX)

The disk can be mounted as read-only by many nodes.

For more information on the kubevirt-storage-class-defaults configmap, see Storage defaults for DataVolumes.

Pasting in a pre-configured YAML file to create a virtual machine

Create a virtual machine by writing or pasting a YAML configuration file. A valid example virtual machine configuration is provided by default whenever you open the YAML edit screen.

If your YAML configuration is invalid when you click Create, an error message indicates the parameter in which the error occurs. Only one error is shown at a time.

Navigating away from the YAML screen while editing cancels any changes to the configuration you have made.
Procedure

  1. Click Workloads → Virtualization from the side menu.

  2. Click the Virtual Machines tab.

  3. Click Create Virtual Machine and select New from YAML.

  4. Write or paste your virtual machine configuration in the editable window.

    1. Alternatively, use the example virtual machine provided by default in the YAML screen.

  5. Optional: Click Download to download the YAML configuration file in its present state.

  6. Click Create to create the virtual machine.

The virtual machine is listed in the Virtual Machines tab.

Using the CLI to create a virtual machine

Procedure

The spec object of the VirtualMachine configuration file references the virtual machine settings, such as the number of cores and the amount of memory, the disk type, and the volumes to use.

  1. Attach the virtual machine disk to the virtual machine by referencing the relevant PVC claimName as a volume.

  2. To create a virtual machine with the OpenShift Container Platform client, run this command:

    $ oc create -f <vm.yaml>

  3. Since virtual machines are created in a Stopped state, run a virtual machine instance by starting it.

A ReplicaSet’s purpose is often used to guarantee the availability of a specified number of identical pods. ReplicaSet is not currently supported in OpenShift Virtualization.
Domain settings
Setting Description

Cores

The number of cores inside the virtual machine. Must be a value greater than or equal to 1.

Memory

The amount of RAM that is allocated to the virtual machine by the node. Specify a value in M for Megabyte or Gi for Gigabyte.

Disks

The name of the volume that is referenced. Must match the name of a volume.
Volume settings
Setting Description

Name

The name of the volume, which must be a DNS label and unique within the virtual machine.

PersistentVolumeClaim

The PVC to attach to the virtual machine. The claimName of the PVC must be in the same project as the virtual machine.

Virtual machine storage volume types

Storage volume 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

DataVolumes 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 filesystems 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.

Additional resources

The VirtualMachineSpec definition in the KubeVirt v0.30.5 API Reference provides broader context for the parameters and hierarchy of the virtual machine specification.

The KubeVirt API Reference is the upstream project reference and might contain parameters that are not supported in OpenShift Virtualization.