About Windows Container Support for Red Hat OpenShift

Windows Container Support for Red Hat OpenShift enables running Windows compute nodes in an OKD cluster. This 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.

Getting support

You must have a subscription to receive support for the Red Hat WMCO. Deploying Windows container workloads in production clusters is not supported without a subscription. If you do not have a subscription, you can use the community WMCO, a distribution that lacks official support. Request support through the Red Hat Customer Portal.

Release notes for Red Hat Windows Machine Config Operator 3.0.0

This release of the WMCO provides bug fixes and enhancements for running Windows compute nodes in an OKD cluster. The components of the WMCO 3.0.0 were released in RHSA-2021:3001.

Users running WMCO 2.0.2 and below must uninstall the operator and reinstall WMCO 3.0.0 to work around a known issue that prevents users from upgrading from WMCO 2.0.2 to WMCO 3.0.0. (BZ#1983153)

Windows Machine Config Operator prerequisites

The following information details the supported cloud provider 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.

Supported cloud providers based on OKD and WMCO versions

Cloud provider Supported OKD version Supported WMCO version

Amazon Web Services (AWS)

4.6+

WMCO 1.0+

Microsoft Azure

4.6+

WMCO 1.0+

VMware vSphere

4.7+

WMCO 2.0+

Supported Windows Server versions

The following table lists the supported Windows Server version based on the applicable cloud provider. Any unlisted Windows Server version is not supported and will cause errors. To prevent these errors, only use the appropriate version according to the cloud provider in use.

Cloud provider Supported Windows Server version

Amazon Web Services (AWS)

Windows Server Long-Term Servicing Channel (LTSC): Windows Server 1809

Microsoft Azure

Windows Server Long-Term Servicing Channel (LTSC): Windows Server 1809

VMware vSphere

Windows Server Semi-Annual Channel (SAC): Windows Server 2004

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 cloud provider. 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.

Table 1. Cloud provider networking support
Cloud provider 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

Table 2. Hybrid OVN-Kubernetes Windows Server support
Hybrid networking with OVN-Kubernetes Supported Windows Server version

Default VXLAN port

Windows Server Long-Term Servicing Channel (LTSC): Windows Server 1809

Custom VXLAN port

Windows Server Semi-Annual Channel (SAC): Windows Server 2004

Supported installation method

The installer-provisioned infrastructure installation method is the only supported installation method. This is consistent across all supported cloud providers. User-provisioned infrastructure installation method is not supported.

Running Windows container workloads is not supported for clusters in a restricted network or disconnected environment.

Version 3.x of the WMCO is only compatible with OKD 4.8.

New features and improvements

This release adds the following new features and improvements.

Clarified limits on custom VXLAN port selection

Users must not select a custom VXLAN port when using the latest version of Windows server.

Bug fixes

  • Previously, the load balancer service would become unstable when the backing deployment had multiple pods scheduled on different Windows nodes. This issue has been fixed. (BZ#1905950)

  • Previously, WMCO added the public key annotation windowsmachineconfig.openshift.io/pub-key-hash to Linux nodes. Now, WMCO no longer adds an annotation to Linux nodes. (BZ#1930791)

  • Previously, when users provided an invalid private key, the WMCO would fail. With this update, the WMCO produces an error alerting the user of an invalid key. (BZ#1929579)

  • Previously, the kube-proxy service would crash upon the creation of a load balancer service when the backing development had multiple pods scheduled on different Windows nodes. This issue has now been fixed. (BZ#1939968)

  • Previously, the windows_exporter component reported various metrics as windows_*. This error caused some of the node-level metrics that provide insight into the nodes through telemetry services to go unreported. Now, the componets export correctly showing all of the expected metrics. (BZ#1948037)

RHSA-2021:3001 - Windows Container support for OKD security update

As part of the previously noted bug fix (BZ#1946538), an update for Windows kube-proxy is now available for Red Hat Windows Machine Config Operator 2.0.1. Details of the update are documented in the RHSA-2021:2130 advisory.

Known issues

  • The file system graphs available in the web console do not display for Windows nodes. This is caused by changes in the file system queries. This will be fixed in a future release of WMCO. (BZ#1930347)