Windows Machine Config Bootstrapper

Bootstrapper is the entity responsible for bootstrapping a Windows node. The current scope of this component is to perform an one shot configuration of the Windows node to ensure that it can be become a worker node. Following are the jobs that the bootstrapper does:

• Parse the worker ignition file to get the bootstrap kubeconfig
• Ensures that the kubelet gets the correct kubelet config
• Run the kubelet as a windows service

Once the bootstrapper has been run and the CSR associated with the Windows node is approved, the Windows node will have a taint called os=Windows:NoSchedule, only the pods with matching toleration can be scheduled onto the Windows node. An example pod spec with the toleration would be:

tolerations:
  - key: "os"
    operator: "Equal"
    value: "Windows"
    effect: "NoSchedule"

This will be remotely invoked from a Ansible script or can be run locally

Requirements

• Must be run on Windows server 2019
• Must be run as administrator
• A worker ignition file generated by the cluster must be on disk
• The kubelet you wish to use must be on disk. Currently we support v1.16.2
• If running on AWS, the Windows instance must have the same tags as the other worker nodes in the cluster

Usage

make build

wmcb initialize-kubelet --ignition-file $IGNITION_FILE_PATH --kubelet-path $KUBELET_PATH

The initialize-kubelet command provides the following optional parameters:

• --cluster-dns is the DNS server IP passed to kubelet, that will be used to configure all containers for DNS resolution. If unset, kubelet will determine the DNS server to use. See clusterDNS option in KubeletConfiguration.

Testing

Windows Machine Config Bootstrapper

End to end testing

The following environment variables need to be set for running the end to end tests:

• ARTIFACT_DIR
  • This can be set to any directory
• AWS_SHARED_CREDENTIALS_FILE
  • Set this to point to your AWS credentials file
• KUBE_SSH_KEY_PATH
  • The ssh key used to bring up the VM
• WMCB_IMAGE
  • Registry url for remote WMCB image that needs to be tested. eg. quay.io//:

To build the WMCB image, execute:

podman build -f Dockerfile.tools -t quay.io/<USERNAME>/<IMAGE>:<TAG> .

The WMCB image needs to be pushed to a remote repository:

podman push quay.io/<USERNAME>/<IMAGE>:<TAG>

Once the above variables are set, you can run the unit and end to end tests by executing:

$ hack/run-wmcb-ci-e2e-test.sh

Inorder to skip MachineSet setup, add -skipVMSetup argument to args field in internal/test/wmcb/deploy/job.yaml. A MachineSet with label machine.openshift.io/os-id=Windows needs to be created, and the Machine should be in Provisioned state in order to use -skipVMSetup. Test suite will use the mounted private key to access the Machine created. Using an already Provisioned VM would reduce the wait time to run the test from 12 minute to just 1 minute.