Chapter 2. Release notes
2.1. Red Hat OpenShift support for Windows Containers release notes
You can review the release notes to learn about the changes introduced through each release of the Red Hat OpenShift support for Windows Containers and the Windows Machine Config Operator (WMCO).
2.1.1. Release notes for Red Hat Windows Machine Config Operator 10.22.1
Issued: 28 July 2026
You can review the release notes to learn about the bug fixes and Common Vulnerabilities and Exposures (CVEs) fixes in the Windows Machine Config Operator (WMCO) version 10.22.1.
The components of the WMCO version 10.22.1 were released in RHSA-2026:47173.
2.1.1.1. Bug fixes
- Before this update, the SSH connection between the WMCO and a Windows node would terminate when the WMCO rebooted the node after a configuration update. As a consequence, the WMCO incorrectly treated the SSH disconnection as a reboot failure, preventing the Windows node from completing required reboots. With this release, the reboot validation process is modified to ignore SSH termination errors and instead verify a successful reboot by using explicit node reachability checks and the SSH reconnection. As a result, Windows nodes successfully reboot upon node configuration changes. (OCPBUGS-98228)
2.1.1.2. CVE fixes
2.2. Release notes for past releases of the Windows Machine Config Operator
You can review the release notes to learn about changes in previous versions of the Windows Machine Config Operator (WMCO).
For the current Red Hat OpenShift support for Windows Containers release notes, see "Red Hat OpenShift support for Windows Containers release notes".
2.2.1. Release notes for Red Hat Windows Machine Config Operator 10.22.0
Issued: 20 May 2026
You can review the following release notes to learn about the new features and bug fixes in the Windows Machine Config Operator (WMCO) version 10.22.0.
The components of the WMCO version 10.22.0 were released in RHBA-2026:19710.
2.2.1.1. New features and improvements
- Windows Server 2025 support
- The WMCO now supports Windows Server 2025, OS Build 10.0.26100 or later for all supported platforms.
- Kubernetes upgrade
- The WMCO now uses Kubernetes version 1.35.
2.2.1.2. Bug fixes
-
Before this update, if you enabled the
ClusterAPIMachineManagementfeature gate by enabling theTechPreviewNoUpgradefeature set, OpenShift Container Platform provisioned theopenshift-cluster-apinamespace. However, the WMCO was not adding thewindows-user-datasecret to that namespace, which is required by Cluster API compute machine sets. Because of the missing secret, CAPI-provisioned Windows machines would not bootstrap, remaining stuck in thePendingphase, and never joining the cluster. With this release, the OpenShift Container Platform now detects whether theopenshift-cluster-apinamespace exists and mirrors thewindows-user-datasecret into that namespace. CAPI-provisioned Windows machines successfully receive the bootstrap secret, are no longer getting stuck inPendingstate, and join the cluster as expected. (OCPBUGS-38401)
2.3. Windows Machine Config Operator prerequisites
You can review the following information for details on the supported platform versions, Windows Server versions, and networking configurations for the Windows Machine Config Operator (WMCO). See the vSphere documentation for any information that is relevant to only that platform.
2.3.1. WMCO supported installation method
The WMCO fully supports installing Windows nodes into installer-provisioned infrastructure (IPI) clusters. This is the preferred OpenShift Container Platform installation method.
For user-provisioned infrastructure (UPI) clusters, the WMCO supports installing Windows nodes only into a UPI cluster installed with the platform: none field set in the install-config.yaml file (bare-metal or provider-agnostic) and only for the BYOH (Bring Your Own Host) use case. UPI is not supported for any other platform.
2.3.2. WMCO supported platforms and Windows Server versions
The following table lists the Windows Server versions that are supported by WMCO 10.20.0, based on the applicable platform. Windows Server versions not listed are not supported and attempting to use them will cause errors. To prevent these errors, use only an appropriate version for your platform.
| Platform | Supported Windows Server version |
|---|---|
| Amazon Web Services (AWS) |
|
| Microsoft Azure |
|
| VMware vSphere |
|
| Google Cloud |
|
| Nutanix |
|
| Bare metal or provider agnostic |
|
- For disconnected clusters, the Windows AMI must have the EC2LaunchV2 agent version 2.0.2107 or later installed. For more information, see "Install the latest version of EC2Launch v2 (AWS documentation)".
2.3.3. Supported networking
Hybrid networking with OVN-Kubernetes is the only supported networking configuration. See the additional resources below for more information on this functionality. The following tables outline the type of networking configuration and Windows Server versions to use based on your platform. You must specify the network configuration when you install the cluster.
- The WMCO does not support OVN-Kubernetes without hybrid networking or OpenShift SDN.
- Dual NIC is not supported on WMCO-managed Windows instances.
| Platform | Supported networking |
|---|---|
| Amazon Web Services (AWS) | Hybrid networking with OVN-Kubernetes |
| Microsoft Azure | Hybrid networking with OVN-Kubernetes |
| VMware vSphere | Hybrid networking with OVN-Kubernetes with a custom VXLAN port |
| Google Cloud | Hybrid networking with OVN-Kubernetes |
| Nutanix | Hybrid networking with OVN-Kubernetes |
| Bare metal or provider agnostic | Hybrid networking with OVN-Kubernetes |
| Hybrid networking with OVN-Kubernetes | Supported Windows Server version |
|---|---|
| Default VXLAN port |
|
| Custom VXLAN port |
|
2.4. Windows Machine Config Operator known limitations
Note the following limitations when working with Windows nodes managed by the WMCO (Windows nodes):
The following OpenShift Container Platform features are not supported on Windows nodes:
- Image builds
- OpenShift Pipelines
- OpenShift Service Mesh
- OpenShift monitoring of user-defined projects
- OpenShift Serverless
- Vertical Pod Autoscaling
- Hosted Control Planes
The following Red Hat features are not supported on Windows nodes:
- Dual NIC is not supported on WMCO-managed Windows instances.
- Windows nodes do not support workloads created by using deployment configs. You can use a deployment or other method to deploy workloads.
- Red Hat OpenShift support for Windows Containers does not support adding Windows nodes to a cluster through a trunk port. The only supported networking configuration for adding Windows nodes is through an access port that carries traffic for the VLAN.
- Red Hat OpenShift support for Windows Containers does not support any Windows operating system language other than English (United States).
-
Due to a limitation within the Windows operating system,
clusterNetworkCIDR addresses of class E, such as240.0.0.0, are not compatible with Windows nodes. Kubernetes has identified the following node feature limitations. For more information, see "Compatibility and limitations (Kubernetes documenation)".
- Huge pages are not supported for Windows containers.
- Privileged containers are not supported for Windows containers.
- Kubernetes has identified several API compatibility issues. For more information, see "API compatibility (Kubernetes documenation)".
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