Red Hat OpenShift support for Windows Containers release notes

About Red Hat OpenShift support for Windows Containers

Windows Container Support for Red Hat OpenShift enables running Windows compute nodes in an OKD cluster. Running Windows workloads is possible by using the Red Hat Windows Machine Config Operator (WMCO) to install and manage Windows nodes. With Windows nodes available, you can run Windows container workloads in OKD.

The release notes for Red Hat OpenShift for Windows Containers tracks the development of the WMCO, which provides all Windows container workload capabilities in OKD.

Release notes for Red Hat Windows Machine Config Operator 8.0.0

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 8.0.0 were released in RHSA-2023:1372.

New features and improvements

Support for the pod os parameter

You can now use the spec.os.name.windows parameter in your workload pods to authoritatively identify the pod operating system for validation and to enforce Windows-specific pod security context constraints (SCCs). It is recommended that you configure this parameter in your workload pods.

For more information, see Sample Windows container workload deployment.

WICD logs are added to must-gather

The must-gather tool now collects the service logs generated by the Windows Instance Config Daemon (WICD) from Windows nodes.

Bug fixes

• Previously, the test to determine if the Windows Defender antivirus service is running was incorrectly checking for any process whose name started with Windows Defender, regardless of state. This resulted in an error when the WMCO created firewall exclusions for containerd on instances without Windows Defender installed. This fix now checks for the presence of the specific running process associated with the Windows Defender antivirus service. As a result, the WMCO can properly configure Windows instances as nodes regardless of whether Windows Defender is installed. (OCPBUGS-1513)

• Previously, in-tree storage was not working for Windows nodes on VMware vSphere. With this fix, Red Hat OpenShift support for Windows Containers properly supports in-tree storage for all cloud providers. (WINC-1014)

Windows Machine Config Operator prerequisites

The following information details the supported platform versions, Windows Server versions, and networking configurations for the Windows Machine Config Operator. See the vSphere documentation for any information that is relevant to only that platform.

WMCO 8.0.0 supported platforms and Windows Server versions

The following table lists the Windows Server versions that are supported by WMCO 8.0.0, 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.

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. Be aware that OpenShift SDN networking is the default network for OKD clusters. However, OpenShift SDN is not supported by WMCO.

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:

  • Red Hat cost management

  • Red Hat OpenShift Local

• 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 use a cluster-wide proxy. This is because the WMCO is not able to route traffic through the proxy connection for the 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 supports only in-tree storage drivers for all cloud providers.

• 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.