The release notes for Red Hat OpenShift for Windows Containers tracks the development of the Windows Machine Config Operator (WMCO), which provides all Windows container workload capabilities in OpenShift Container Platform.

Windows Machine Config Operator numbering

Starting with this release, y-stream releases of the WMCO will be in step with OpenShift Container Platform, with only z-stream releases between OpenShift Container Platform releases. The WMCO numbering reflects the associated OpenShift Container Platform version in the y-stream position. For example, the current release of WMCO is associated with OpenShift Container Platform version 4.15. Thus, the numbering is WMCO 10.15.z.

Release notes for Red Hat Windows Machine Config Operator 10.15.2

This release of the WMCO provides new features and bug fixes for running Windows compute nodes in an OpenShift Container Platform cluster. The components of the WMCO 10.15.2 were released in RHBA-2024:2704.

Bug fixes

  • Previously, on Azure clusters the WMCO would check if an external Cloud Controller Manager (CCM) was being used on the cluster. CCM use is the default. If a CCM is being used, the Operator would adjust configuration logic accordingly. Because the status condition that the WMCO used to check for the CCM was removed, the WMCO proceeded as if a CCM was not in use. This fix removes the check. As a result, the WMCO always configures the required logic on Azure clusters. (OCPBUGS-31704)

  • Previously, the kubelet was unable to authenticate with private Elastic Container Registries (ECR) registries. Because of this error, the kubelet was not able to pull images from these registries. With this fix, the kubelet is able to pull images from these registries as expected. (OCPBUGS-26602)

  • Previously, the WMCO was logging error messages when any commands being run through an SSH connection to a Windows instance failed. This was incorrect behavior because some commands are expected to fail. For example, when WMCO reboots a node the Operator runs PowerShell commands on the instance until they fail, meaning the SSH connection rebooted as expected. With this fix, only actualy errors are now logged. (OCPBUGS-20255)

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

    • Horizontal Pod Autoscaling

    • Vertical Pod Autoscaling

  • The following Red Hat features are not supported on Windows nodes:

  • Windows nodes do not support pulling container images from private registries. You can use images from public registries or pre-pull the images.

  • Windows nodes do not support workloads created by using deployment configs. You can use a deployment or other method to deploy workloads.

  • Windows nodes are not supported in clusters that are in a disconnected environment.

  • 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).

  • Kubernetes has identified the following node feature limitations :

    • Huge pages are not supported for Windows containers.

    • Privileged containers are not supported for Windows containers.

  • Kubernetes has identified several API compatibility issues.