Azure container service not creating the agent nodes

As the documentation points out, ACS with a target of Kubernetes is deprecated. You want to use AKS (Azure Kubernetes as a Service).

To go about this, start here: https://docs.microsoft.com/en-us/azure/aks/windows-container-cli

Make sure you have the latest version of the CLI installed on your machine if you choose to do it locally, or use the Azure Cloud Shell.

Follow the guide on the rest of the steps as it will walk you through the commands.

For your issue, as I know the possible reason is that you need to enable the WindowsPreview feather. You can have a check through the CLI command like this:

az feature list -o table --query "[?contains(name, 'Microsoft.ContainerService/WindowsPreview')].{Name:name,State:properties.state}"

When it's OK, you also need to pay attention to the Kubernetes version. When I use the command that you have used, then the windows nodes are created successfully, but it just shows the master when I execute the command kubectl get nodes. Even if I can see the windows node in the group.

Then I try the command with additional parameter --orchestrator-version and set the value as 1.12.7 and the whole command like below:

az acs create --orchestrator-type=kubernetes \    --resource-group myResourceGroup \    --name=myK8sCluster \    --agent-count=2 \    --generate-ssh-keys \    --windows --admin-username azureuser \    --admin-password myPassword12 \    --orchestrator-version \    --location westcentralus

Then it works well and the command kubectl get nodes -o wide show like below:

But as you know, the ACS will be deprecated. So I would suggest you use the AKS with Windows node in the preview version. Or you can use the aks-engine as the AKS Engine is the next version of the ACS-Engine project.