This walkthrough shows how to setup a Private Link Service with an AKS cluster and create a Private Endpoint in a separate Vnet.
While many tutorials might give you a full ARM template, this is designed as a walkthrough which completely uses the CLI so you can understand what’s happening at every step of the process.
It focuses on an “uninteresting” workload and uses podinfo as the sample app. This is because it’s easy to deploy and customize with a sample Helm chart.
This is inspired and leans heavily on the Azure Docs for creating a Private Link Service.
Architecture
Prerequisites
Assumptions
This walkthrough assumes you let Azure create the Vnet when creating the AKS cluster. If you manually created the Vnet, then the general steps are the same, except you must enter the AKS_MC_VNET, AKS_MC_SUBNET env vars manually.
Setup Steps
First, create a sample AKS cluster and install Podinfo on it.
# Set these values
AKS_NAME=
AKS_RG=
LOCATION=
# Create the AKS cluster
az aks create -n $AKS_NAME -g $AKS_RG
# Get the MC Resource Group
AKS_MC_RG=$(az aks show -n $AKS_NAME -g $AKS_RG | jq -r '.nodeResourceGroup')
echo $AKS_MC_RG
# Get the Vnet Name
AKS_MC_VNET=$(az network vnet list -g $AKS_MC_RG | jq -r '.[0].name')
echo $AKS_MC_VNET
AKS_MC_SUBNET=$(az network vnet subnet list -g $AKS_MC_RG --vnet-name $AKS_MC_VNET | jq -r '.[0].name')
echo $AKS_MC_SUBNET
AKS_MC_LB_INTERNAL=kubernetes-internal
AKS_MC_LB_INTERNAL_FE_CONFIG=$(az network lb rule list -g $AKS_MC_RG --lb-name=$AKS_MC_LB_INTERNAL | jq -r '.[0].frontendIpConfiguration.id')
echo $AKS_MC_LB_INTERNAL_FE_CONFIG
# Deploy a sample app using an Internal LB
helm upgrade --install --wait podinfo-internal-lb \
--set-string service.annotations."service\.beta\.kubernetes\.io\/azure-load-balancer-internal"=true \
--set service.type=LoadBalancer \
--set ui.message=podinfo-internal-lb \
podinfo/podinfo
Install Steps – Create the Private Link Service
These steps will be done in the MC_ resource group.
# Disable the private link service network policies
az network vnet subnet update \
--name $AKS_MC_SUBNET \
--resource-group $AKS_MC_RG \
--vnet-name $AKS_MC_VNET \
--disable-private-link-service-network-policies true
# Create the PLS
PLS_NAME=aks-pls
az network private-link-service create \
--resource-group $AKS_MC_RG \
--name $PLS_NAME \
--vnet-name $AKS_MC_VNET \
--subnet $AKS_MC_SUBNET \
--lb-name $AKS_MC_LB_INTERNAL \
--lb-frontend-ip-configs $AKS_MC_LB_INTERNAL_FE_CONFIG
Install Steps – Create the Private Endpoint
These steps will be done in our private-endpoint-rg
resource group.
PE_RG=private-endpoint-rg
az group create \
--name $PE_RG \
--location $LOCATION
PE_VNET=pe-vnet
PE_SUBNET=pe-subnet
az network vnet create \
--resource-group $PE_RG \
--name $PE_VNET \
--address-prefixes 10.0.0.0/16 \
--subnet-name $PE_SUBNET \
--subnet-prefixes 10.0.0.0/24
# Disable the private link service network policies
az network vnet subnet update \
--name $PE_SUBNET \
--resource-group $PE_RG \
--vnet-name $PE_VNET \
--disable-private-endpoint-network-policies true
PE_CONN_NAME=pe-conn
PE_NAME=pe
az network private-endpoint create \
--connection-name $PE_CONN_NAME \
--name $PE_NAME \
--private-connection-resource-id $PLS_ID \
--resource-group $PE_RG \
--subnet $PE_SUBNET \
--manual-request false \
--vnet-name $PE_VNET
# We need the NIC ID to get the newly created Private IP
PE_NIC_ID=$(az network private-endpoint show -g $PE_RG --name $PE_NAME -o json | jq -r '.networkInterfaces[0].id')
echo $PE_NIC_ID
# Get the Private IP from the NIC
PE_IP=$(az network nic show --ids $PE_NIC_ID -o json | jq -r '.ipConfigurations[0].privateIpAddress')
echo $PE_IP
Validation Steps – Create a VM
Lastly, validate that this works by creating a VM in the Vnet with the Private Endpoint.
VM_NAME=ubuntu
az vm create \
--resource-group $PE_RG \
--name ubuntu \
--image UbuntuLTS \
--public-ip-sku Standard \
--vnet-name $PE_VNET \
--subnet $PE_SUBNET \
--admin-username $USER \
--ssh-key-values ~/.ssh/id_rsa.pub
VM_PIP=$(az vm list-ip-addresses -g $PE_RG -n $VM_NAME | jq -r '.[0].virtualMachine.network.publicIpAddresses[0].ipAddress')
echo $VM_PIP
# SSH into the host
ssh $VM_IP
$ curl COPY_THE_VALUE_FROM_PE_IP:9898
# The output should look like:
$ curl 10.0.0.5:9898
{
"hostname": "podinfo-6ff68cbf88-cxcvv",
"version": "6.0.3",
"revision": "",
"color": "#34577c",
"logo": "https://raw.githubusercontent.com/stefanprodan/podinfo/gh-pages/cuddle_clap.gif",
"message": "podinfo-internal-lb",
"goos": "linux",
"goarch": "amd64",
"runtime": "go1.16.9",
"num_goroutine": "9",
"num_cpu": "2"
}
Multiple PLS/PE
To test a specific use case, I wanted to create multiple PLS and PE’s. This set of instructions lets you easily loop through and create multiple instances.
# podinfo requires a high numbered port, eg 9000+
SUFFIX=9000
helm upgrade --install --wait podinfo-$SUFFIX \
--set-string service.annotations."service\.beta\.kubernetes\.io\/azure-load-balancer-internal"=true \
--set service.type=LoadBalancer \
--set service.httpPort=$SUFFIX \
--set service.externalPort=$SUFFIX \
--set ui.message=podinfo-$SUFFIX \
podinfo/podinfo
# This might be easier to hard-code
AKS_MC_LB_INTERNAL_FE_CONFIG=$(az network lb rule list -g $AKS_MC_RG --lb-name=$AKS_MC_LB_INTERNAL -o json | jq -r ".[] | select( .backendPort == $SUFFIX) | .frontendIpConfiguration.id")
echo $AKS_MC_LB_INTERNAL_FE_CONFIG
PLS_NAME=aks-pls-$SUFFIX
PE_CONN_NAME=pe-conn-$SUFFIX
PE_NAME=pe-$SUFFIX
az network private-link-service create \
--resource-group $AKS_MC_RG \
--name $PLS_NAME \
--vnet-name $AKS_MC_VNET \
--subnet $AKS_MC_SUBNET \
--lb-name $AKS_MC_LB_INTERNAL \
--lb-frontend-ip-configs $AKS_MC_LB_INTERNAL_FE_CONFIG
PLS_ID=$(az network private-link-service show \
--name $PLS_NAME \
--resource-group $AKS_MC_RG \
--query id \
--output tsv)
echo $PLS_ID
az network private-endpoint create \
--connection-name $PE_CONN_NAME \
--name $PE_NAME \
--private-connection-resource-id $PLS_ID \
--resource-group $PE_RG \
--subnet $PE_SUBNET \
--manual-request false \
--vnet-name $PE_VNET
PE_NIC_ID=$(az network private-endpoint show -g $PE_RG --name $PE_NAME -o json | jq -r '.networkInterfaces[0].id')
echo $PE_NIC_ID
PE_IP=$(az network nic show --ids $PE_NIC_ID -o json | jq -r '.ipConfigurations[0].privateIpAddress')
echo $PE_IP
echo "From your Private Endpoint VM run: curl $PE_IP:$SUFFIX"
I created this article to help myself (and hopefully you!) to clearly understand all of the resources and how they interact to create a Private Link Service and Private Endpoint fronting a private service inside an AKS cluster. This has been highly enlightening for me and I hope it has for you too.