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Preparing your cluster for OKD Virtualization

Review platform compatibility information before you install OKD Virtualization. For detailed system requirements, see "Hardware, software, and operational requirements" in the Additional resources section.

Compatible platforms

OKD Virtualization supports bare-metal servers, ARM64-based systems, and IBM Z® or IBM® LinuxONE systems in logical partitions.

Compatible platforms

  • On-premise bare-metal servers. For more information, see "Planning a bare-metal cluster for OKD Virtualization" in the Additional resources section.

  • Bare-metal clusters installed on ARM64-based (arm64, also known as aarch64) systems.

  • IBM Z® or IBM® LinuxONE (s390x architecture) systems where an OKD cluster is installed in logical partitions (LPARs). For more information, see "Preparing to install on IBM Z and IBM LinuxONE" in the Additional resources section.

Cloud platforms

OKD Virtualization is compatible with various public cloud platforms, each with specific storage options and support levels.

Vendor Status Storage Resources

Amazon Web Services (AWS)

GA

  • Elastic Block Store (EBS)

  • Red Hat OpenShift Data Foundation (ODF)

  • Portworx

  • FSx (NetApp)

For more information, see "Installing a cluster on AWS with customizations" in the Additional resources section.

Red Hat OpenShift Service on AWS (ROSA)

GA

  • EBS

  • Portworx

  • FSx (Q3)

  • ODF

Oracle Cloud Infrastructure (OCI)

GA

  • OCI native storage

Azure Red Hat OpenShift (ARO)

GA

  • ODF

Google Cloud

Technology Preview

  • Google Cloud native storage

Bare-metal instances or servers offered by other cloud providers are not supported.

For platform-specific networking information, see "Networking overview" in the Additional resources section.

OKD Virtualization on AWS bare metal

You can run OKD Virtualization on an Amazon Web Services (AWS) bare metal OKD cluster.

OKD Virtualization is also supported on Red Hat OpenShift Service on AWS (ROSA) Classic clusters, which have the same configuration requirements as AWS bare-metal clusters.

Before you set up your cluster, review the following summary of supported features and limitations:

Installing

  • You can install the cluster by using installer-provisioned infrastructure, ensuring that you specify bare-metal instance types for the worker nodes. For example, you can use the c5n.metal type value for a machine based on x86_64 architecture. You specify bare-metal instance types by editing the install-config.yaml file.

    For more information, see the OKD documentation about installing on AWS.

Accessing virtual machines (VMs)

  • There is no change to how you access VMs by using the virtctl CLI tool or the OKD web console.

  • You can expose VMs by using a NodePort or LoadBalancer service.

    The load balancer approach is preferable because OKD automatically creates the load balancer in AWS and manages its lifecycle. A security group is also created for the load balancer, and you can use annotations to attach existing security groups. When you remove the service, OKD removes the load balancer and its associated resources.
Networking

  • You cannot use Single Root I/O Virtualization (SR-IOV) or bridge Container Network Interface (CNI) networks, including virtual LAN (VLAN). If your application requires a flat layer 2 network or control over the IP pool, consider using OVN-Kubernetes secondary overlay networks.

Storage

  • You can use any storage solution that is certified by the storage vendor to work with the underlying platform.

    AWS bare metal, Red Hat OpenShift Service on AWS, and Red Hat OpenShift Service on AWS classic architecture clusters might have different supported storage solutions. Ensure that you confirm support with your storage vendor.

  • Using Amazon Elastic File System (EFS) or Amazon Elastic Block Store (EBS) with OKD Virtualization might cause performance and functionality limitations as shown in the following table:

    Table 1. EFS and EBS performance and functionality limitations
    Feature EBS volume EFS volume Shared storage solutions

    gp2

    gp3

    io2

    VM live migration

    Not available

    Not available

    Available

    Available

    Available

    Fast VM creation by using cloning

    Available

    Not available

    Available

    VM backup and restore by using snapshots

    Available

    Not available

    Available

    Consider using CSI storage, which supports ReadWriteMany (RWX), cloning, and snapshots to enable live migration, fast VM creation, and VM snapshots capabilities.

Hosted control planes (HCPs)

  • HCPs for OKD Virtualization are not currently supported on AWS infrastructure.

ARM64 compatibility

OKD Virtualization on ARM64 systems is generally available (GA) with specific limitations for operating systems and live migration.

Before using OKD Virtualization on an ARM64-based system, consider the following limitations:

Operating system
Live migration

  • Live migration is not supported on ARM64-based OKD clusters.

  • Hotplug is not supported on ARM64-based clusters because it depends on live migration.

VM creation

  • Fedora 10 supports instance types and preferences, but not templates.

  • Fedora 9 supports templates, instance types, and preferences.

IBM Z and IBM LinuxONE compatibility

You can use OKD Virtualization in an OKD cluster that is installed in logical partitions (LPARs) on an IBM Z® or IBM® LinuxONE (s390x architecture) system.

Some features are not currently available on s390x architecture, while others require workarounds or procedural changes. These lists are subject to change.

Currently unavailable features

The following features are currently not available on s390x architecture:

  • Memory hot plugging and hot unplugging

  • Node Health Check Operator

  • SR-IOV Operator

  • PCI passthrough

  • OKD Virtualization cluster checkup framework

  • OKD Virtualization on a cluster installed in FIPS mode

  • IPv6

  • IBM® Storage scale

  • Hosted control planes for OKD Virtualization

  • VM pages using HugePages

    The following features are not applicable on s390x architecture:

  • virtual Trusted Platform Module (vTPM) devices

  • UEFI mode for VMs

  • USB host passthrough

  • Configuring virtual GPUs

  • Creating and managing Windows VMs

  • Hyper-V

Functionality differences

The following features are available for use on s390x architecture but function differently or require procedural changes:

  • When deleting a virtual machine by using the web console, the grace period option is ignored. For more information, see "Deleting a virtual machine by using the web console" in the Additional resources section.

  • When configuring the default CPU model, the spec.defaultCPUModel value is "gen15b" for an IBM Z cluster. For more information, see "Configuring the default CPU model" in the Additional resources section.

  • When configuring a downward metrics device, if you use a VM preference, the spec.preference.name value must be set to rhel.9.s390x or another available preference with the format *.s390x. For more information, see "Configuring a downward metrics device" in the Additional resources section.

  • When creating virtual machines from instance types, you are not allowed to set spec.domain.memory.maxGuest because memory hot plugging is not supported on IBM Z®. For more information, see "Creating virtual machines from instance types" in the Additional resources section.

  • Prometheus queries for VM guests could have inconsistent outcome in comparison to x86.

Important considerations for any platform

Before installing OKD Virtualization, note key considerations about installation methods, storage, IPv6, and FIPS mode.

Installation method considerations

You can use any installation method, including user-provisioned, installer-provisioned, or Assisted Installer, to deploy OKD. However, the installation method and the cluster topology might affect OKD Virtualization functionality, such as snapshots or live migration. For more information about live migration, see "Hardware, software, and operational requirements" in the Additional resources section.

Red Hat OpenShift Data Foundation

If you deploy OKD Virtualization with Red Hat OpenShift Data Foundation, you must create a dedicated storage class for Windows virtual machine disks. For more information, see "Optimizing ODF PersistentVolumes for Windows VMs" in the Additional resources section.

IPv6

OKD Virtualization support for single-stack IPv6 clusters is limited to the OVN-Kubernetes localnet and Linux bridge Container Network Interface (CNI) plugins.

{FeatureName} 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.
FIPS mode

If you install your cluster in FIPS mode, no additional setup is required for OKD Virtualization. For more information, see "Installing a FIPS-compliant cluster" in the Additional resources section.

Object maximums

Consider tested object maximums for both OKD and OKD Virtualization when planning your cluster.

OKD

See "OKD object maximums" in the Additional resources section.

OKD Virtualization

See "OKD Virtualization supported limits" in the Additional resources section.

Additional resources