Create and configure an Azure Kubernetes Services (AKS) cluster to use virtual nodes using Azure CLI
Virtual nodes enable network communication between pods that run in Azure Container Instances (ACI) and AKS clusters. To provide this communication, you create a virtual network subnet and assign delegated permissions. Virtual nodes only work with AKS clusters created using advanced networking (Azure CNI). By default, AKS clusters are created with basic networking (kubenet). This article shows you how to create a virtual network and subnets, then deploy an AKS cluster that uses advanced networking.
This article shows you how to use the Azure CLI to create and configure virtual network resources and an AKS cluster enabled with virtual nodes.
Before you begin
Important
Before using virtual nodes with AKS, review both the limitations of AKS virtual nodes and the virtual networking limitations of ACI. These limitations affect the location, networking configuration, and other configuration details of both your AKS cluster and the virtual nodes.
You need the ACI service provider registered with your subscription. You can check the status of the ACI provider registration using the
az provider list
command.az provider list --query "[?contains(namespace,'Microsoft.ContainerInstance')]" -o table
The Microsoft.ContainerInstance provider should report as Registered, as shown in the following example output:
Namespace RegistrationState RegistrationPolicy --------------------------- ------------------- -------------------- Microsoft.ContainerInstance Registered RegistrationRequired
If the provider shows as NotRegistered, register the provider using the
az provider register
.az provider register --namespace Microsoft.ContainerInstance
If using Azure CLI, this article requires Azure CLI version 2.0.49 or later. Run
az --version
to find the version. If you need to install or upgrade, see Install Azure CLI. You can also use Azure Cloud Shell.
Launch Azure Cloud Shell
The Azure Cloud Shell is a free interactive shell you can use to run the steps in this article. It has common Azure tools preinstalled and configured.
To open the Cloud Shell, select Try it from the upper right corner of a code block. You can also launch Cloud Shell in a separate browser tab by going to https://shell.azure.com/bash. Select Copy to copy the blocks of code, paste it into the Cloud Shell, and press enter to run it.
Create a resource group
An Azure resource group is a logical group in which Azure resources are deployed and managed.
Create a resource group using the
az group create
command.az group create --name myResourceGroup --location eastus
Create a virtual network
Important
Virtual node requires a custom virtual network and associated subnet. It can't be associated with the same virtual network as the AKS cluster.
Create a virtual network using the
az network vnet create
command. The following example creates a virtual network named myVnet with an address prefix of 10.0.0.0/8 and a subnet named myAKSSubnet. The address prefix of this subnet defaults to 10.240.0.0/16.az network vnet create \ --resource-group myResourceGroup \ --name myVnet \ --address-prefixes 10.0.0.0/8 \ --subnet-name myAKSSubnet \ --subnet-prefix 10.240.0.0/16
Create an extra subnet for the virtual nodes using the
az network vnet subnet create
command. The following example creates a subnet named myVirtualNodeSubnet with an address prefix of 10.241.0.0/16.az network vnet subnet create \ --resource-group myResourceGroup \ --vnet-name myVnet \ --name myVirtualNodeSubnet \ --address-prefixes 10.241.0.0/16
Create an AKS cluster with managed identity
Get the subnet ID using the
az network vnet subnet show
command.az network vnet subnet show --resource-group myResourceGroup --vnet-name myVnet --name myAKSSubnet --query id -o tsv
Create an AKS cluster using the
az aks create
command and replace<subnetId>
with the ID obtained in the previous step. The following example creates a cluster named myAKSCluster with five nodes.az aks create \ --resource-group myResourceGroup \ --name myAKSCluster \ --node-count 5 \ --network-plugin azure \ --vnet-subnet-id <subnetId> \ --generate-ssh-keys
After several minutes, the command completes and returns JSON-formatted information about the cluster.
For more information on managed identities, see Use managed identities.
Enable the virtual nodes addon
Enable virtual nodes using the
az aks enable-addons
command. The following example uses the subnet named myVirtualNodeSubnet created in a previous step.az aks enable-addons \ --resource-group myResourceGroup \ --name myAKSCluster \ --addons virtual-node \ --subnet-name myVirtualNodeSubnet
Connect to the cluster
Configure
kubectl
to connect to your Kubernetes cluster using theaz aks get-credentials
command. This step downloads credentials and configures the Kubernetes CLI to use them.az aks get-credentials --resource-group myResourceGroup --name myAKSCluster
Verify the connection to your cluster using the
kubectl get
command, which returns a list of the cluster nodes.kubectl get nodes
The following example output shows the single VM node created and the virtual node for Linux, virtual-node-aci-linux:
NAME STATUS ROLES AGE VERSION virtual-node-aci-linux Ready agent 28m v1.11.2 aks-agentpool-14693408-0 Ready agent 32m v1.11.2
Deploy a sample app
Create a file named
virtual-node.yaml
and copy in the following YAML. The YAML schedules the container on the node by defining a nodeSelector and toleration.apiVersion: apps/v1 kind: Deployment metadata: name: aci-helloworld spec: replicas: 1 selector: matchLabels: app: aci-helloworld template: metadata: labels: app: aci-helloworld spec: containers: - name: aci-helloworld image: mcr.microsoft.com/azuredocs/aci-helloworld ports: - containerPort: 80 nodeSelector: kubernetes.io/role: agent beta.kubernetes.io/os: linux type: virtual-kubelet tolerations: - key: virtual-kubelet.io/provider operator: Exists - key: azure.com/aci effect: NoSchedule
Run the application using the
kubectl apply
command.kubectl apply -f virtual-node.yaml
Get a list of pods and the scheduled node using the
kubectl get pods
command with the-o wide
argument.kubectl get pods -o wide
The pod is scheduled on the virtual node virtual-node-aci-linux, as shown in the following example output:
NAME READY STATUS RESTARTS AGE IP NODE aci-helloworld-9b55975f-bnmfl 1/1 Running 0 4m 10.241.0.4 virtual-node-aci-linux
The pod is assigned an internal IP address from the Azure virtual network subnet delegated for use with virtual nodes.
Note
If you use images stored in Azure Container Registry, configure and use a Kubernetes secret. A current limitation of virtual nodes is you can't use integrated Microsoft Entra service principal authentication. If you don't use a secret, pods scheduled on virtual nodes fail to start and report the error HTTP response status code 400 error code "InaccessibleImage"
.
Test the virtual node pod
Test the pod running on the virtual node by browsing to the demo application with a web client. As the pod is assigned an internal IP address, you can quickly test this connectivity from another pod on the AKS cluster.
Create a test pod and attach a terminal session to it using the following
kubectl run -it
command.kubectl run -it --rm testvk --image=mcr.microsoft.com/dotnet/runtime-deps:6.0
Install
curl
in the pod usingapt-get
.apt-get update && apt-get install -y curl
Access the address of your pod using
curl
, such as http://10.241.0.4. Provide your own internal IP address shown in the previouskubectl get pods
command.curl -L http://10.241.0.4
The demo application is displayed, as shown in the following condensed example output:
<html> <head> <title>Welcome to Azure Container Instances!</title> </head> [...]
Close the terminal session to your test pod with
exit
. When your session is ends, the pod is deleted.
Remove virtual nodes
Delete the
aci-helloworld
pod running on the virtual node using thekubectl delete
command.kubectl delete -f virtual-node.yaml
Disable the virtual nodes using the
az aks disable-addons
command.az aks disable-addons --resource-group myResourceGroup --name myAKSCluster --addons virtual-node
Remove the virtual network resources and resource group using the following commands.
# Change the name of your resource group, cluster and network resources as needed RES_GROUP=myResourceGroup AKS_CLUSTER=myAKScluster AKS_VNET=myVnet AKS_SUBNET=myVirtualNodeSubnet # Get AKS node resource group NODE_RES_GROUP=$(az aks show --resource-group $RES_GROUP --name $AKS_CLUSTER --query nodeResourceGroup --output tsv) # Get network profile ID NETWORK_PROFILE_ID=$(az network profile list --resource-group $NODE_RES_GROUP --query "[0].id" --output tsv) # Delete the network profile az network profile delete --id $NETWORK_PROFILE_ID -y # Grab the service association link ID SAL_ID=$(az network vnet subnet show --resource-group $RES_GROUP --vnet-name $AKS_VNET --name $AKS_SUBNET --query id --output tsv)/providers/Microsoft.ContainerInstance/serviceAssociationLinks/default # Delete the service association link for the subnet az resource delete --ids $SAL_ID --api-version 2021-10-01 # Delete the subnet delegation to Azure Container Instances az network vnet subnet update --resource-group $RES_GROUP --vnet-name $AKS_VNET --name $AKS_SUBNET --remove delegations
Next steps
In this article, you scheduled a pod on the virtual node and assigned a private internal IP address. You could instead create a service deployment and route traffic to your pod through a load balancer or ingress controller. For more information, see Create a basic ingress controller in AKS.
Virtual nodes are often one component of a scaling solution in AKS. For more information on scaling solutions, see the following articles:
Azure Kubernetes Service