1. Proposed Title of this Feature Request:

Support for Windows Worker Nodes in Hypershift Hosted Control Plane Clusters

2. Nature and Description of the Request:

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This RFE proposes the implementation of functionality within Hypershift to allow the addition and management of Windows-based worker nodes to Hosted Control Plane (HCP) clusters.

Currently, Hypershift HCP clusters are restricted to using only RHCOS (Red Hat CoreOS) nodes as worker nodes. This enhancement would involve developing the necessary logic, tooling, and integrations within Hypershift to provision, configure, and lifecycle manage Windows Server instances as worker nodes, enabling them to join the OpenShift cluster and run Windows-based workloads.

This would include:

Provisioning: Mechanism to provision Windows Server VMs (e.g., in AWS, Azure, GCP or BareMetal) that can be integrated as worker nodes.

Configuration: Automated configuration of Windows nodes to enable them to function as OpenShift workers, including installing necessary OpenShift components (e.g., kubelet, kube-proxy, CNI plugins compatible with Windows).

Networking: Ensuring proper network integration and communication between Windows nodes and the OpenShift cluster.

Lifecycle Management: Support for upgrades, scaling, and general maintenance of Windows worker nodes within the Hypershift paradigm.

Monitoring and Logging: Integration with OpenShift's monitoring and logging frameworks for Windows nodes.

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3. Why does the customer need this? (Business Requirements)

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The customer's primary driver for this feature is to optimize resource utilization and reduce operational costs by migrating from their existing vSphere environment to OpenShift Bare Metal, specifically leveraging Hypershift Hosted Control Planes (HCP).

Here's a breakdown of their specific business needs:

Significant Cost and Space Savings: The customer aims to transition to OpenShift Bare Metal and utilize HCP to eliminate the need for dedicated master nodes on-premises. With an estimated eight clusters, this translates to a saving of 24 bare metal master hosts. These savings are critical because dedicated master hosts consume valuable datacenter space and incur substantial hardware, power, cooling, and maintenance costs. The customer currently lacks the physical space and budget for these additional hosts.

Enablement of Windows Workloads on HCP: A core requirement is the ability to run Windows worker nodes on almost all of their OpenShift clusters. Their proprietary products are fundamentally built and operated on Windows, making Windows node support non-negotiable for their migration strategy.

Resolution of a Critical Migration Blocker: The current lack of Windows node support within HCP creates a significant roadblock for their planned migration. This limitation directly causes the aforementioned resource, cost, and space issues, jeopardizing their ability to switch from vSphere to OpenShift Bare Metal.

Seamless Transition and Future-Proofing: Official support for Windows nodes within HCP would provide a smooth path for their migration, avoiding the need for complex workarounds or compromises. It would also ensure their OpenShift environment can continue to support their core Windows-based products efficiently and cost-effectively into the future.

The other customers may have a different business requirement:

Consolidation and Simplification of Infrastructure: The ability to run both Linux and Windows workloads within the same OpenShift cluster simplifies infrastructure management, reduces operational overhead, and eliminates the need for separate management planes or platforms for different operating systems. This leads to a more streamlined and efficient IT environment.

Application Modernization for Mixed Environments: Customers are increasingly adopting hybrid and multi-cloud strategies, and their applications often have dependencies across both Linux and Windows components. Supporting Windows nodes enables these customers to modernize their applications within a unified OpenShift ecosystem, fostering true cloud-native development for mixed environments.

Compliance and Licensing Requirements: Certain applications may have strict licensing or compliance requirements that mandate them to run on the Windows operating system. To bring these applications under OpenShift management, Windows node support is essential.

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4. Affected Packages or Components:

Hosted Control Plane