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Red Hat OpenShift support for Windows Containers release notes

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 OKD.

Windows Machine Config Operator numbering

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

Release notes for Red Hat Windows Machine Config Operator 10.15.3

This release of the WMCO provides new features and bug fixes for running Windows compute nodes in an OKD cluster. The components of the WMCO 10.15.3 were released in RHSA-2024:5745.

Bug fixes

  • Previously, after rotating the kube-apiserver-to-kubelet-client-ca certificate, the contents of the kubetl-ca.crt file on Windows nodes was not populated correctly. With this fix, after certificate rotation, the kubetl-ca.crt file contains the correct certificates. (OCPBUGS-33875)

  • Previously, if reverse DNS lookup failed due to an error, such as the reverse DNS lookup services being unavailable, the WMCO would not fall back to using the VM hostname to determine if a certificate signing requests (CSR) should be approved. As a consequence, Bring-Your-Own-Host (BYOH) Windows nodes configured with an IP address would not become available. With this fix, BYOH nodes are properly added if reverse DNS is not available. (OCPBUGS-37533)

  • Previously, if there were multiple service account token secrets in the WMCO namespace, the scaling of Windows nodes would fail. With this fix, the WMCO uses only the secret it creates, ignoring any other service account token secrets in the WMCO namespace. As a result, Windows nodes scale properly. (OCPBUGS-38485)

Known limitations

Note the following limitations when working with Windows nodes managed by the WMCO (Windows nodes):

  • The following OKD 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:

  • 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.

  • 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).

  • Due to a limitation within the Windows operating system, clusterNetwork CIDR addresses of class E, such as 240.0.0.0, are not compatible with Windows nodes.

  • 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.