ci: Use explicit templates for Windows infra (#5906)

* ci: Use explicit templates for Windows infra

* omit Windows pool from ClusterClass test scenario

* use new machine-pool-windows template for VMSS test

* add a separate Windows test

* non-Windows test scenario should not test Windows LB

* use shorter “win” name to avoid API issues

Author: jackfrancis

docs/book/src/developers/development.md

@@ -586,7 +586,7 @@ You can optionally set the following variables:
 | `CI_VERSION`                | Provide a custom CI version of Kubernetes (e.g., `v1.25.0-alpha.0.597+aa49dffc7f24dc`). If not specified, this will be determined from the KUBERNETES_VERSION above if it is an unreleased version. If you provide a `CI_VERSION` environment variable, you may not also use `KUBERNETES_VERSION` (above).                                                                                                                                                                                                                         |
 | `TEST_CCM`                  | Build a cluster that uses custom versions of the Azure cloud-provider cloud-controller-manager and node-controller-manager images                                                                                                                                                                                                                                                                                                                                                                                                  |
 | `EXP_MACHINE_POOL`          | Use [Machine Pool](../self-managed/machinepools.md) for worker machines. Defaults to true.                                                                                                                                                                                                                                                                                                                                                                   |
-| `TEST_WINDOWS`              | Build a cluster that has Windows worker nodes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
+| `TEST_WINDOWS`              | Set to "true" to build a cluster that has Windows worker nodes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
 | `REGISTRY`                  | Registry to push any custom k8s images or cloud provider images built.                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
 | `CLUSTER_TEMPLATE`          | Use a custom cluster template. It can be a path to a template under templates/, a path on the host or a link. If the value is not set, the script will choose the appropriate cluster template based on existing environment variables.                                                                                                                                                                                                                                                                                            |
 | `CCM_COUNT`                 | Set the number of cloud-controller-manager only when `TEST_CCM` is set. Besides it should not be more than control plane Node number.                                                                                                                                                                                                                                                                                                                                                                                              |

scripts/ci-entrypoint.sh

@@ -117,7 +117,7 @@ setup() {
     export EXP_CLUSTER_RESOURCE_SET="true"
 
     # TODO figure out a better way to account for expected Windows node count
-    if [[ -n "${TEST_WINDOWS:-}" ]]; then
+    if [[ "${TEST_WINDOWS:-}" == "true" ]]; then
         export WINDOWS_WORKER_MACHINE_COUNT="${WINDOWS_WORKER_MACHINE_COUNT:-2}"
     fi
 }
@@ -139,6 +139,10 @@ select_cluster_template() {
             export CLUSTER_TEMPLATE="${CLUSTER_TEMPLATE/custom-builds/custom-builds-machine-pool}"
         fi
     fi
+
+    if [[ "${TEST_WINDOWS:-}" == "true" ]]; then
+        export CLUSTER_TEMPLATE="${CLUSTER_TEMPLATE/.yaml/-windows.yaml}"
+    fi
 }
 
 create_cluster() {