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You can create a Windows MachineSet object to serve a specific purpose in your OpenShift Container Platform cluster on VMware vSphere. For example, you might create infrastructure Windows machine sets and related machines so that you can move supporting Windows workloads to the new Windows machines.

Prerequisites

  • You installed the Windows Machine Config Operator (WMCO) using Operator Lifecycle Manager (OLM).

  • You are using a supported Windows Server as the operating system image.

Machine API overview

The Machine API is a combination of primary resources that are based on the upstream Cluster API project and custom OpenShift Container Platform resources.

For OpenShift Container Platform 4.11 clusters, the Machine API performs all node host provisioning management actions after the cluster installation finishes. Because of this system, OpenShift Container Platform 4.11 offers an elastic, dynamic provisioning method on top of public or private cloud infrastructure.

The two primary resources are:

Machines

A fundamental unit that describes the host for a node. A machine has a providerSpec specification, which describes the types of compute nodes that are offered for different cloud platforms. For example, a machine type for a worker node on Amazon Web Services (AWS) might define a specific machine type and required metadata.

Machine sets

MachineSet resources are groups of machines. Machine sets are to machines as replica sets are to pods. If you need more machines or must scale them down, you change the replicas field on the machine set to meet your compute need.

Control plane machines cannot be managed by machine sets.

The following custom resources add more capabilities to your cluster:

Machine autoscaler

The MachineAutoscaler resource automatically scales machines in a cloud. You can set the minimum and maximum scaling boundaries for nodes in a specified machine set, and the machine autoscaler maintains that range of nodes. The MachineAutoscaler object takes effect after a ClusterAutoscaler object exists. Both ClusterAutoscaler and MachineAutoscaler resources are made available by the ClusterAutoscalerOperator object.

Cluster autoscaler

This resource is based on the upstream cluster autoscaler project. In the OpenShift Container Platform implementation, it is integrated with the Machine API by extending the machine set API. You can set cluster-wide scaling limits for resources such as cores, nodes, memory, GPU, and so on. You can set the priority so that the cluster prioritizes pods so that new nodes are not brought online for less important pods. You can also set the scaling policy so that you can scale up nodes but not scale them down.

Machine health check

The MachineHealthCheck resource detects when a machine is unhealthy, deletes it, and, on supported platforms, makes a new machine.

In OpenShift Container Platform version 3.11, you could not roll out a multi-zone architecture easily because the cluster did not manage machine provisioning. Beginning with OpenShift Container Platform version 4.1, this process is easier. Each machine set is scoped to a single zone, so the installation program sends out machine sets across availability zones on your behalf. And then because your compute is dynamic, and in the face of a zone failure, you always have a zone for when you must rebalance your machines. In global Azure regions that do not have multiple availability zones, you can use availability sets to ensure high availability. The autoscaler provides best-effort balancing over the life of a cluster.

Preparing your vSphere environment for Windows container workloads

You must prepare your vSphere environment for Windows container workloads by creating the vSphere Windows VM golden image and enabling communication with the internal API server for the WMCO.

Creating the vSphere Windows VM golden image

Create a vSphere Windows virtual machine (VM) golden image.

Prerequisites
  • You have created a private/public key pair, which is used to configure key-based authentication in the OpenSSH server. The private key must also be configured in the Windows Machine Config Operator (WMCO) namespace. This is required to allow the WMCO to communicate with the Windows VM. See the "Configuring a secret for the Windows Machine Config Operator" section for more details.

You must use Microsoft PowerShell commands in several cases when creating your Windows VM. PowerShell commands in this guide are distinguished by the PS C:\> prefix.

Procedure
  1. Select a compatible Windows Server version. Currently, the Windows Machine Config Operator (WMCO) stable version supports Windows Server 2022 Long-Term Servicing Channel with the OS-level container networking patch KB5012637.

  2. Create a new VM in the vSphere client using the VM golden image with a compatible Windows Server version. For more information about compatible versions, see the "Windows Machine Config Operator prerequisites" section of the "Red Hat OpenShift support for Windows Containers release notes."

    The virtual hardware version for your VM must meet the infrastructure requirements for OpenShift Container Platform. For more information, see the "VMware vSphere infrastructure requirements" section in the OpenShift Container Platform documentation. Also, you can refer to VMware’s documentation on virtual machine hardware versions.

  3. Install and configure VMware Tools version 11.0.6 or greater on the Windows VM. See the VMware Tools documentation for more information.

  4. After installing VMware Tools on the Windows VM, verify the following:

    1. The C:\ProgramData\VMware\VMware Tools\tools.conf file exists with the following entry:

      exclude-nics=

      If the tools.conf file does not exist, create it with the exclude-nics option uncommented and set as an empty value.

      This entry ensures the cloned vNIC generated on the Windows VM by the hybrid-overlay is not ignored.

    2. The Windows VM has a valid IP address in vCenter:

      C:\> ipconfig
    3. The VMTools Windows service is running:

      PS C:\> Get-Service -Name VMTools | Select Status, StartType
  5. Install and configure the OpenSSH Server on the Windows VM. See Microsoft’s documentation on installing OpenSSH for more details.

  6. Set up SSH access for an administrative user. See Microsoft’s documentation on the Administrative user to do this.

    The public key used in the instructions must correspond to the private key you create later in the WMCO namespace that holds your secret. See the "Configuring a secret for the Windows Machine Config Operator" section for more details.

  7. You must create a new firewall rule in the Windows VM that allows incoming connections for container logs. Run the following PowerShell command to create the firewall rule on TCP port 10250:

    PS C:\> New-NetFirewallRule -DisplayName "ContainerLogsPort" -LocalPort 10250 -Enabled True -Direction Inbound -Protocol TCP -Action Allow -EdgeTraversalPolicy Allow
  8. Clone the Windows VM so it is a reusable image. Follow the VMware documentation on how to clone an existing virtual machine for more details.

  9. In the cloned Windows VM, run the Windows Sysprep tool:

    C:\> C:\Windows\System32\Sysprep\sysprep.exe /generalize /oobe /shutdown /unattend:<path_to_unattend.xml> (1)
    1 Specify the path to your unattend.xml file.

    There is a limit on how many times you can run the sysprep command on a Windows image. Consult Microsoft’s documentation for more information.

    An example unattend.xml is provided, which maintains all the changes needed for the WMCO. You must modify this example; it cannot be used directly.

    Example unattend.xml
    <?xml version="1.0" encoding="UTF-8"?>
    <unattend xmlns="urn:schemas-microsoft-com:unattend">
       <settings pass="specialize">
          <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-International-Core" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
             <InputLocale>0409:00000409</InputLocale>
             <SystemLocale>en-US</SystemLocale>
             <UILanguage>en-US</UILanguage>
             <UILanguageFallback>en-US</UILanguageFallback>
             <UserLocale>en-US</UserLocale>
          </component>
          <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Security-SPP-UX" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
             <SkipAutoActivation>true</SkipAutoActivation>
          </component>
          <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-SQMApi" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
             <CEIPEnabled>0</CEIPEnabled>
          </component>
          <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
             <ComputerName>winhost</ComputerName> (1)
          </component>
       </settings>
       <settings pass="oobeSystem">
          <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
             <AutoLogon>
                <Enabled>false</Enabled> (2)
             </AutoLogon>
             <OOBE>
                <HideEULAPage>true</HideEULAPage>
                <HideLocalAccountScreen>true</HideLocalAccountScreen>
                <HideOEMRegistrationScreen>true</HideOEMRegistrationScreen>
                <HideOnlineAccountScreens>true</HideOnlineAccountScreens>
                <HideWirelessSetupInOOBE>true</HideWirelessSetupInOOBE>
                <NetworkLocation>Work</NetworkLocation>
                <ProtectYourPC>1</ProtectYourPC>
                <SkipMachineOOBE>true</SkipMachineOOBE>
                <SkipUserOOBE>true</SkipUserOOBE>
             </OOBE>
             <RegisteredOrganization>Organization</RegisteredOrganization>
             <RegisteredOwner>Owner</RegisteredOwner>
             <DisableAutoDaylightTimeSet>false</DisableAutoDaylightTimeSet>
             <TimeZone>Eastern Standard Time</TimeZone>
             <UserAccounts>
                <AdministratorPassword>
                   <Value>MyPassword</Value> (3)
                   <PlainText>true</PlainText>
                </AdministratorPassword>
             </UserAccounts>
          </component>
       </settings>
    </unattend>
    1 Specify the ComputerName, which must follow the Kubernetes' names specification. These specifications also apply to Guest OS customization performed on the resulting template while creating new VMs.
    2 Disable the automatic logon to avoid the security issue of leaving an open terminal with Administrator privileges at boot. This is the default value and must not be changed.
    3 Replace the MyPassword placeholder with the password for the Administrator account. This prevents the built-in Administrator account from having a blank password by default. Follow Microsoft’s best practices for choosing a password.

    After the Sysprep tool has completed, the Windows VM will power off. You must not use or power on this VM anymore.

  10. Convert the Windows VM to a template in vCenter.

Enabling communication with the internal API server for the WMCO on vSphere

The Windows Machine Config Operator (WMCO) downloads the Ignition config files from the internal API server endpoint. You must enable communication with the internal API server so that your Windows virtual machine (VM) can download the Ignition config files, and the kubelet on the configured VM can only communicate with the internal API server.

Prerequisites
  • You have installed a cluster on vSphere.

Procedure
  • Add a new DNS entry for api-int.<cluster_name>.<base_domain> that points to the external API server URL api.<cluster_name>.<base_domain>. This can be a CNAME or an additional A record.

The external API endpoint was already created as part of the initial cluster installation on vSphere.