Deploy to hybrid Linux/Windows Kubernetes clusters
How to run Dapr apps on Kubernetes clusters with windows nodes
Dapr supports running on kubernetes clusters with windows nodes. You can run your Dapr microservices exclusively on Windows, exclusively on Linux, or a combination of both. This is helpful to users who may be doing a piecemeal migration of a legacy application into a Dapr Kubernetes cluster.
Kubernetes uses a concept called node affinity so that you can denote whether you want your application to be launched on a Linux node or a Windows node. When deploying to a cluster which has both Windows and Linux nodes, you must provide affinity rules for your applications, otherwise the Kubernetes scheduler might launch your application on the wrong type of node.
Pre-requisites
You will need a Kubernetes cluster with Windows nodes. Many Kubernetes providers support the automatic provisioning of Windows enabled Kubernetes clusters.
- Follow your preferred provider’s instructions for setting up a cluster with Windows enabled
Once you have set up the cluster, you should see that it has both Windows and Linux nodes available
kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
aks-nodepool1-11819434-vmss000000 Ready agent 6d v1.17.9 10.240.0.4 <none> Ubuntu 16.04.6 LTS 4.15.0-1092-azure docker://3.0.10+azure
aks-nodepool1-11819434-vmss000001 Ready agent 6d v1.17.9 10.240.0.35 <none> Ubuntu 16.04.6 LTS 4.15.0-1092-azure docker://3.0.10+azure
aks-nodepool1-11819434-vmss000002 Ready agent 5d10h v1.17.9 10.240.0.129 <none> Ubuntu 16.04.6 LTS 4.15.0-1092-azure docker://3.0.10+azure
akswin000000 Ready agent 6d v1.17.9 10.240.0.66 <none> Windows Server 2019 Datacenter 10.0.17763.1339 docker://19.3.5
akswin000001 Ready agent 6d v1.17.9 10.240.0.97 <none> Windows Server 2019 Datacenter 10.0.17763.1339 docker://19.3.5
Installing the Dapr control plane
If you are installing using the Dapr CLI or via a helm chart, simply follow the normal deployment procedures: Installing Dapr on a Kubernetes cluster
Affinity will be automatically set for kubernetes.io/os=linux
. This will be sufficient for most users, as Kubernetes requires at least one Linux node pool.
Note: Dapr control plane containers are built and tested for both windows and linux, however, we generally recommend using the linux control plane containers. They tend to be smaller and have a much larger user base.
If you understand the above, but want to deploy the Dapr control plane to Windows, you can do so by setting:
helm install dapr dapr/dapr --set global.daprControlPlaneOs=windows
Installing Dapr applications
Windows applications
In order to launch a Dapr application on Windows, you’ll first need to create a Docker container with your application installed. For a step by step guide see Get started: Prep Windows for containers. Once you have a docker container with your application, create a deployment YAML file with node affinity set to kubernetes.io/os: windows.
Create a deployment YAML
Here is a sample deployment with nodeAffinity set to “windows”. Modify as needed for your application.
apiVersion: apps/v1
kind: Deployment
metadata:
name: yourwinapp
labels:
app: applabel
spec:
replicas: 1
selector:
matchLabels:
app: applablel
template:
metadata:
labels:
app: applabel
annotations:
dapr.io/enabled: "true"
dapr.io/id: "addapp"
dapr.io/port: "6000"
dapr.io/config: "appconfig"
spec:
containers:
- name: add
image: yourreponsitory/your-windows-dapr-container:your-tag
ports:
- containerPort: 6000
imagePullPolicy: Always
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/os
operator: In
values:
- windows
This deployment yaml will be the same as any other dapr application, with an additional spec.template.spec.affinity section as shown above.
Deploy to your Kubernetes cluster
kubectl apply -f deploy_windows.yaml
Linux applications
If you have already got a dapr application with runs on Linux, you’ll still need to add affinity rules as above, but choose linux affinity instead.
Create a deployment YAML
Here is a sample deployment with nodeAffinity set to “linux”. Modify as needed for your application.
apiVersion: apps/v1
kind: Deployment
metadata:
name: yourlinuxapp
labels:
app: yourlabel
spec:
replicas: 1
selector:
matchLabels:
app: yourlabel
template:
metadata:
labels:
app: yourlabel
annotations:
dapr.io/enabled: "true"
dapr.io/id: "addapp"
dapr.io/port: "6000"
dapr.io/config: "appconfig"
spec:
containers:
- name: add
image: yourreponsitory/your-application:your-tag
ports:
- containerPort: 6000
imagePullPolicy: Always
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/os
operator: In
values:
- linux
Deploy to your Kubernetes cluster
kubectl apply -f deploy_linux.yaml
Cleanup
kubectl delete -f deploy_linux.yaml
kubectl delete -f deploy_windows.yaml
helm uninstall dapr
Related links
- See the official Kubernetes documentation for examples of more advanced configuration via node affinity
- Get started: Prep Windows for containers
- Setting up a Windows enabled Kubernetes cluster on Azure AKS
- Setting up a Windows enabled Kubernetes cluster on AWS EKS
- Setting up Windows on Google Cloud GKE
Last modified March 18, 2021: Merge pull request #1321 from dapr/aacrawfi/logos (9a399d5)