Available as of v2.3.0

When provisioning a custom cluster using Rancher, Rancher uses RKE (the Rancher Kubernetes Engine) to provision the Kubernetes custom cluster on your existing infrastructure.

You can use a mix of Linux and Windows hosts as your cluster nodes. Windows nodes can only be used for deploying workloads, while Linux nodes are required for cluster management.

You can only add Windows nodes to a cluster if Windows support is enabled. Windows support can be enabled for new custom clusters that use Kubernetes 1.15+ and the Flannel network provider. Windows support cannot be enabled for existing clusters.

Windows clusters have more requirements than Linux clusters. For example, Windows nodes must have 50 GB of disk space. Make sure your Windows cluster fulfills all of the requirements.

For a summary of Kubernetes features supported in Windows, see the Kubernetes documentation on supported functionality and limitations for using Kubernetes with Windows or the guide for scheduling Windows containers in Kubernetes.

This guide covers the following topics:

Prerequisites

Before provisioning a new cluster, be sure that you have already installed Rancher on a device that accepts inbound network traffic. This is required in order for the cluster nodes to communicate with Rancher. If you have not already installed Rancher, please refer to the installation documentation before proceeding with this guide.

Note on Cloud Providers: If you set a Kubernetes cloud provider in your cluster, some additional steps are required. You might want to set a cloud provider if you want to want to leverage a cloud provider’s capabilities, for example, to automatically provision storage, load balancers, or other infrastructure for your cluster. Refer to this page for details on how to configure a cloud provider cluster of nodes that meet the prerequisites.

Requirements for Windows Clusters

For a custom cluster, the general node requirements for networking, operating systems, and Docker are the same as the node requirements for a Rancher installation.

OS and Docker Requirements

In order to add Windows worker nodes to a cluster, the node must be running one of the following Windows Server versions and the corresponding version of Docker:

  • Windows Server core version 1809 and Docker 18.09
  • Windows server core version 1903 and Docker 19.03

The nodes must run Docker Engine - Enterprise Edition (EE).

Nodes with Windows Server core version 1809 should use Docker EE-basic 18.09.

Nodes with Windows Server core version 1903 should use Docker EE-basic 19.03.

Notes:

  • If you are using AWS, Rancher recommends Microsoft Windows Server 2019 Base with Containers as the Amazon Machine Image (AMI).
  • If you are using GCE, Rancher recommends Windows Server 2019 Datacenter for Containers as the OS image.

Node Requirements

The hosts in the cluster need to have at least:

  • 2 core CPUs
  • 5 GB memory
  • 50 GB disk space

Rancher will not provision the node if the node does not meet these requirements.

Networking Requirements

Rancher only supports Windows using Flannel as the network provider.

There are two network options: Host Gateway (L2bridge) and VXLAN (Overlay). The default option is VXLAN (Overlay) mode.

For Host Gateway (L2bridge) networking, it’s best to use the same Layer 2 network for all nodes. Otherwise, you need to configure the route rules for them. For details, refer to the documentation on configuring cloud-hosted VM routes. You will also need to disable private IP address checks if you are using Amazon EC2, Google GCE, or Azure VM.

For VXLAN (Overlay) networking, the KB4489899 hotfix must be installed. Most cloud-hosted VMs already have this hotfix.

Architecture Requirements

The Kubernetes cluster management nodes (etcd and controlplane) must be run on Linux nodes.

The worker nodes, which is where your workloads will be deployed on, will typically be Windows nodes, but there must be at least one worker node that is run on Linux in order to run the Rancher cluster agent, DNS, metrics server, and Ingress related containers.

We recommend the minimum three-node architecture listed in the table below, but you can always add additional Linux and Windows workers to scale up your cluster for redundancy:

Node Operating System Kubernetes Cluster Role(s) Purpose
Node 1 Linux (Ubuntu Server 18.04 recommended) Control Plane, etcd, Worker Manage the Kubernetes cluster
Node 2 Linux (Ubuntu Server 18.04 recommended) Worker Support the Rancher Cluster agent, Metrics server, DNS, and Ingress for the cluster
Node 3 Windows (Windows Server core version 1809 or above) Worker Run your Windows containers

Container Requirements

Windows requires that containers must be built on the same Windows Server version that they are being deployed on. Therefore, containers must be built on Windows Server core version 1809 or above. If you have existing containers built for an earlier Windows Server core version, they must be re-built on Windows Server core version 1809 or above.

Tutorial: How to Create a Cluster with Windows Support

This tutorial describes how to create a Rancher-provisioned cluster with the three nodes in the recommended architecture.

When you provision a custom cluster with Rancher, you will add nodes to the cluster by installing the Rancher agent on each one. When you create or edit your cluster from the Rancher UI, you will see a Customize Node Run Command that you can run on each server to add it to your custom cluster.

To set up a custom cluster with support for Windows nodes and containers, you will need to complete the tasks below.

  1. Provision Hosts
  2. Create the Custom Cluster
  3. Add Nodes to the Cluster
  4. Optional: Configuration for Azure Files

1. Provision Hosts

To begin provisioning a custom cluster with Windows support, prepare your hosts.

Your hosts can be:

  • Cloud-hosted VMs
  • VMs from virtualization clusters
  • Bare-metal servers

You will provision three nodes:

  • One Linux node, which manages the Kubernetes control plane and stores your etcd
  • A second Linux node, which will be another worker node
  • The Windows node, which will run your Windows containers as a worker node
Node Operating System
Node 1 Linux (Ubuntu Server 18.04 recommended)
Node 2 Linux (Ubuntu Server 18.04 recommended)
Node 3 Windows (Windows Server core version 1809 or above required)

If your nodes are hosted by a Cloud Provider and you want automation support such as loadbalancers or persistent storage devices, your nodes have additional configuration requirements. For details, see Selecting Cloud Providers.

2. Create the Custom Cluster

The instructions for creating a custom cluster that supports Windows nodes are very similar to the general instructions for creating a custom cluster with some Windows-specific requirements.

Windows support only be enabled if the cluster uses Kubernetes v1.15+ and the Flannel network provider.

  1. From the Global view, click on the Clusters tab and click Add Cluster.

  2. Click From existing nodes (Custom).

  3. Enter a name for your cluster in the Cluster Name text box.

  4. In the Kubernetes Version dropdown menu, select v1.15 or above.

  5. In the Network Provider field, select Flannel.

  6. In the Windows Support section, click Enable.

  7. Optional: After you enable Windows support, you will be able to choose the Flannel backend. There are two network options: Host Gateway (L2bridge) and VXLAN (Overlay). The default option is VXLAN (Overlay) mode.

  8. Click Next.

Important: For Host Gateway (L2bridge) networking, it’s best to use the same Layer 2 network for all nodes. Otherwise, you need to configure the route rules for them. For details, refer to the documentation on configuring cloud-hosted VM routes. You will also need to disable private IP address checks if you are using Amazon EC2, Google GCE, or Azure VM.

3. Add Nodes to the Cluster

This section describes how to register your Linux and Worker nodes to your custom cluster.

Add Linux Master Node

The first node in your cluster should be a Linux host has both the Control Plane and etcd roles. At a minimum, both of these roles must be enabled for this node, and this node must be added to your cluster before you can add Windows hosts.

In this section, we fill out a form on the Rancher UI to get a custom command to install the Rancher agent on the Linux master node. Then we will copy the command and run it on our Linux master node to register the node in the cluster.

  1. In the Node Operating System section, click Linux.

  2. In the Node Role section, choose at least etcd and Control Plane. We recommend selecting all three.

  3. Optional: If you click Show advanced options, you can customize the settings for the Rancher agent and node labels.

  4. Copy the command displayed on the screen to your clipboard.

  5. SSH into your Linux host and run the command that you copied to your clipboard.

  6. When you are finished provisioning your Linux node(s), select Done.

Result:

  • Your cluster is created and assigned a state of Provisioning. Rancher is standing up your cluster.
  • You can access your cluster after its state is updated to Active.
  • Active clusters are assigned two Projects, Default (containing the namespace default) and System (containing the namespaces cattle-system,ingress-nginx,kube-public and kube-system, if present).

It may take a few minutes for the node to be registered in your cluster.

Add Linux Worker Node

After the initial provisioning of your custom cluster, your cluster only has a single Linux host. Next, we add another Linux worker host, which will be used to support Rancher cluster agent, Metrics server, DNS and Ingress for your cluster.

  1. From the Global view, click Clusters.

  2. Go to the custom cluster that you created and click Ellipsis (…) > Edit.

  3. Scroll down to Node Operating System. Choose Linux.

  4. In the Customize Node Run Command section, go to the Node Options and select the Worker role.

  5. Copy the command displayed on screen to your clipboard.

  6. Log in to your Linux host using a remote Terminal connection. Run the command copied to your clipboard.

  7. From Rancher, click Save.

Result: The Worker role is installed on your Linux host, and the node registers with Rancher. It may take a few minutes for the node to be registered in your cluster.

Note: Taints on Linux Worker Nodes

For each Linux worker node added into the cluster, the following taints will be added to Linux worker node. By adding this taint to the Linux worker node, any workloads added to the windows cluster will be automatically scheduled to the Windows worker node. If you want to schedule workloads specifically onto the Linux worker node, you will need to add tolerations to those workloads.

Taint Key Taint Value Taint Effect
cattle.io/os linux NoSchedule

Add a Windows Worker Node

You can add Windows hosts to a custom cluster by editing the cluster and choosing the Windows option.

  1. From the Global view, click Clusters.

  2. Go to the custom cluster that you created and click Ellipsis (…) > Edit.

  3. Scroll down to Node Operating System. Choose Windows. Note: You will see that the worker role is the only available role.

  4. Copy the command displayed on screen to your clipboard.

  5. Log in to your Windows host using your preferred tool, such as Microsoft Remote Desktop. Run the command copied to your clipboard in the Command Prompt (CMD).

  6. From Rancher, click Save.

  7. Optional: Repeat these instructions if you want to add more Windows nodes to your cluster.

Result: The Worker role is installed on your Windows host, and the node registers with Rancher. It may take a few minutes for the node to be registered in your cluster. You now have a Windows Kubernetes cluster.

Configuration for Storage Classes in Azure

If you are using Azure VMs for your nodes, you can use Azure files as a storage class for the cluster.

In order to have the Azure platform create the required storage resources, follow these steps:

  1. Configure the Azure cloud provider.

  2. Configure kubectl to connect to your cluster.

  3. Copy the ClusterRole and ClusterRoleBinding manifest for the service account:

    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: ClusterRole
    metadata:
      name: system:azure-cloud-provider
    rules:
    - apiGroups: ['']
      resources: ['secrets']
      verbs:     ['get','create']
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: ClusterRoleBinding
    metadata:
      name: system:azure-cloud-provider
    roleRef:
      kind: ClusterRole
      apiGroup: rbac.authorization.k8s.io
      name: system:azure-cloud-provider
    subjects:
    - kind: ServiceAccount
      name: persistent-volume-binder
      namespace: kube-system
    
  4. Create these in your cluster using one of the follow command.

    # kubectl create -f <MANIFEST>