Considerations Enabling Windows support Deploy a Windows sample application

Windows support

This topic describes how to add Windows support to Amazon EKS clusters.

Considerations

Before deploying Windows nodes, be aware of the following considerations.

Amazon EC2 instance types C3, C4, D2, I2, M4 (excluding m4.16xlarge), and R3 instances are not supported for Windows workloads.
Host networking mode is not supported for Windows workloads.
Amazon EKS clusters must contain one or more Linux nodes to run core system pods that only run on Linux, such as coredns and the VPC resource controller.
The kubelet and kube-proxy event logs are redirected to the EKS Windows Event Log and are set to a 200 MB limit.
You can't use Security groups for pods with pods running on Windows nodes.
Windows nodes support one elastic network interface per node. The number of pods that you can run per Windows node is equal to the number of IP addresses available per elastic network interface for the node's instance type, minus one. For more information, see IP addresses per network interface per instance type in the Amazon EC2 User Guide for Linux Instances.
Group Managed Service Accounts (GMSA) for Windows pods and containers is not supported by Amazon EKS versions earlier than 1.16. You can follow the instructions in the Kubernetes documentation to enable and test this alpha feature on clusters that are earlier than 1.16.
In an Amazon EKS cluster, a single service with a load balancer can support up to 64 backend pods. Each pod has its own unique IP address. This is a limitation of the Windows OS on the Amazon EC2 nodes.
You can't deploy Windows managed or Fargate nodes. You can only create self-managed Windows nodes. For more information, see Launching self-managed Windows nodes.

Enabling Windows support

The following steps help you to enable Windows support for your Amazon EKS cluster. You can use eksctl, a Windows client, or a macOS or Linux client to enable Windows support for your cluster.

eksctl

To enable Windows support for your cluster with eksctl

Prerequisite

This procedure requires eksctl version 0.44.0 or later. You can check your version with the following command.


eksctl version

For more information about installing or upgrading eksctl, see Installing or upgrading eksctl.

Enable Windows support for your Amazon EKS cluster with the following eksctl command. Replace my-cluster with the name of your cluster. This command deploys the VPC resource controller and VPC admission controller webhook that are required on Amazon EKS clusters to run Windows workloads.
```
eksctl utils install-vpc-controllers --cluster my-cluster --approve
```
After you have enabled Windows support, you can launch a Windows node group into your cluster. For more information, see Launching self-managed Windows nodes.

After you add Windows support to your cluster, you must specify node selectors on your applications so that the pods land on a node with the appropriate operating system. For Linux pods, use the following node selector text in your manifests.


nodeSelector:
        kubernetes.io/os: linux
        kubernetes.io/arch: amd64

For Windows pods, use the following node selector text in your manifests.


nodeSelector:
        kubernetes.io/os: windows
        kubernetes.io/arch: amd64

Windows

To enable Windows support for your cluster with a Windows client

In the following steps, replace us-west-2 with the Region that your cluster resides in.

Deploy the VPC resource controller to your cluster.


kubectl apply -f https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-resource-controller/latest/vpc-resource-controller.yaml

Deploy the VPC admission controller webhook to your cluster.

Download the required scripts and deployment files.


curl -o vpc-admission-webhook-deployment.yaml https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-admission-webhook/latest/vpc-admission-webhook-deployment.yaml;
curl -o Setup-VPCAdmissionWebhook.ps1 https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-admission-webhook/latest/Setup-VPCAdmissionWebhook.ps1;
curl -o webhook-create-signed-cert.ps1 https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-admission-webhook/latest/webhook-create-signed-cert.ps1;
curl -o webhook-patch-ca-bundle.ps1 https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-admission-webhook/latest/webhook-patch-ca-bundle.ps1;

Install OpenSSL and jq.

Set up and deploy the VPC admission webhook.


./Setup-VPCAdmissionWebhook.ps1 -DeploymentTemplate ".\vpc-admission-webhook-deployment.yaml"

Determine if your cluster has the required cluster role binding.
```
kubectl get clusterrolebinding eks:kube-proxy-windows
```
If output similar to the following example output is returned, then the cluster has the necessary role binding.
```
NAME                      AGE
eks:kube-proxy-windows    10d
```
If the output includes Error from server (NotFound), then the cluster does not have the necessary cluster role binding. Add the binding by creating a file named eks-kube-proxy-windows-crb.yaml with the following content.
```
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: eks:kube-proxy-windows
  labels:
    k8s-app: kube-proxy
    eks.amazonaws.com/component: kube-proxy
subjects:
  - kind: Group
    name: "eks:kube-proxy-windows"
roleRef:
  kind: ClusterRole
  name: system:node-proxier
  apiGroup: rbac.authorization.k8s.io
```
Apply the configuration to the cluster.
```
kubectl apply -f eks-kube-proxy-windows-crb.yaml
```
After you have enabled Windows support, you can launch a Windows node group into your cluster. For more information, see Launching self-managed Windows nodes.


nodeSelector:
        kubernetes.io/os: linux
        kubernetes.io/arch: amd64

For Windows pods, use the following node selector text in your manifests.


nodeSelector:
        kubernetes.io/os: windows
        kubernetes.io/arch: amd64

macOS and Linux

To enable Windows support for your cluster with a macOS or Linux client

This procedure requires that the openssl library and jq JSON processor are installed on your client system.

In the following steps, replace <region-code> with the Region that your cluster resides in.

Deploy the VPC resource controller to your cluster.


kubectl apply -f https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-resource-controller/latest/vpc-resource-controller.yaml

Create the VPC admission controller webhook manifest for your cluster.

Download the required scripts and deployment files.


curl -o webhook-create-signed-cert.sh https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-admission-webhook/latest/webhook-create-signed-cert.sh
curl -o webhook-patch-ca-bundle.sh https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-admission-webhook/latest/webhook-patch-ca-bundle.sh
curl -o vpc-admission-webhook-deployment.yaml https://s3.us-west-2.amazonaws.com/amazon-eks/manifests/us-west-2/vpc-admission-webhook/latest/vpc-admission-webhook-deployment.yaml

Add permissions to the shell scripts so that they can be run.
```
chmod +x webhook-create-signed-cert.sh webhook-patch-ca-bundle.sh
```
Create a secret for secure communication.
```
./webhook-create-signed-cert.sh
```

Verify the secret.


kubectl get secret -n kube-system vpc-admission-webhook-certs

Configure the webhook and create a deployment file.


cat ./vpc-admission-webhook-deployment.yaml | ./webhook-patch-ca-bundle.sh > vpc-admission-webhook.yaml

Deploy the VPC admission webhook.


kubectl apply -f vpc-admission-webhook.yaml

Determine if your cluster has the required cluster role binding.
```
kubectl get clusterrolebinding eks:kube-proxy-windows
```
If output similar to the following example output is returned, then the cluster has the necessary role binding.
```
NAME                     ROLE                              AGE
eks:kube-proxy-windows   ClusterRole/system:node-proxier   19h
```
If the output includes Error from server (NotFound), then the cluster does not have the necessary cluster role binding. Add the binding by creating a file named eks-kube-proxy-windows-crb.yaml with the following content.
```
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: eks:kube-proxy-windows
  labels:
    k8s-app: kube-proxy
    eks.amazonaws.com/component: kube-proxy
subjects:
  - kind: Group
    name: "eks:kube-proxy-windows"
roleRef:
  kind: ClusterRole
  name: system:node-proxier
  apiGroup: rbac.authorization.k8s.io
```
Apply the configuration to the cluster.
```
kubectl apply -f eks-kube-proxy-windows-crb.yaml
```
After you have enabled Windows support, you can launch a Windows node group into your cluster. For more information, see Launching self-managed Windows nodes.


nodeSelector:
        kubernetes.io/os: linux
        kubernetes.io/arch: amd64

For Windows pods, use the following node selector text in your manifests.


nodeSelector:
        kubernetes.io/os: windows
        kubernetes.io/arch: amd64

Deploy a Windows sample application

To deploy a Windows sample application

Create a file named windows-server-iis.yaml with the following content.


apiVersion: apps/v1
kind: Deployment
metadata:
  name: windows-server-iis
spec:
  selector:
    matchLabels:
      app: windows-server-iis
      tier: backend
      track: stable
  replicas: 1
  template:
    metadata:
      labels:
        app: windows-server-iis
        tier: backend
        track: stable
    spec:
      containers:
      - name: windows-server-iis
        image: mcr.microsoft.com/windows/servercore:1809
        ports:
        - name: http
          containerPort: 80
        imagePullPolicy: IfNotPresent
        command:
        - powershell.exe
        - -command
        - "Add-WindowsFeature Web-Server; Invoke-WebRequest -UseBasicParsing -Uri 'https://dotnetbinaries.blob.core.windows.net/servicemonitor/2.0.1.6/ServiceMonitor.exe' -OutFile 'C:\\ServiceMonitor.exe'; echo '<html><body><br/><br/><marquee><H1>Hello EKS!!!<H1><marquee></body><html>' > C:\\inetpub\\wwwroot\\default.html; C:\\ServiceMonitor.exe 'w3svc'; "
      nodeSelector:
        kubernetes.io/os: windows
---
apiVersion: v1
kind: Service
metadata:
  name: windows-server-iis-service
  namespace: default
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: windows-server-iis
    tier: backend
    track: stable
  sessionAffinity: None
  type: LoadBalancer

Deploy the application to the cluster.


kubectl apply -f windows-server-iis.yaml

Get the status of the pod.
```
kubectl get pods -o wide --watch
```
Wait for the pod to transition to the Running state.
Query the services in your cluster and wait until the External IP column for the windows-server-iis-service service is populated.

Note

It might take several minutes for the IP address to become available.
```
kubectl get services -o wide
```
After your external IP address is available, point a web browser to that address to view the IIS home page.

Note

It might take several minutes for DNS to propagate and for your sample application to load in your web browser.

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