Create a MetalLB load balancer using Azure Arc and Azure CLI

Applies to: Azure Stack HCI, version 23H2

The main purpose of a load balancer is to distribute traffic across multiple nodes in a Kubernetes cluster. This can help prevent downtime and improve overall performance of applications. AKS enabled by Azure Arc supports creating MetalLB load balancer instance on your Kubernetes cluster using the Arc Networking k8s-extension.

Prerequisites

• A Kubernetes cluster with at least one Linux node. You can create a Kubernetes cluster on Azure Stack HCI 23H2 using the Azure CLI or the Azure portal.
• Make sure you have enough IP addresses for the load balancer. Ensure that the IP addresses reserved for the load balancer do not conflict with the IP addresses in Arc VM logical networks and control plane IPs. For more information about IP address planning and networking in Kubernetes, see Networking requirements for AKS on Azure Stack HCI 23H2.
• This how-to guide assumes you understand how Metal LB works. For more information, see the overview for MetalLB in Arc Kubernetes clusters.

Install the Azure CLI extension

Run the following command to install the necessary Azure CLI extension:

az extension add -n k8s-runtime --upgrade

Enable load balancer Arc extension

Configure the following variables before proceeding:

Use the az k8s-runtime load-balancer enable command to install the Arc extension and register the resource provider for your Kubernetes cluster. The --resource-uri parameter refers to the resource manager ID of your AKS Arc cluster.

az k8s-runtime load-balancer enable --resource-uri subscriptions/$subId/resourceGroups/$rgName/providers/Microsoft.Kubernetes/connectedClusters/$clusterName

Deploy MetalLB load balancer on your Kubernetes cluster

You can now create a load balancer for your Kubernetes cluster remotely by running the az k8s-runtime load-balancer create command. This command creates a custom resource of kind IPAddressPool in namespace kube-system.

Configure the following variables before proceeding:

If the advertise mode is BGP or Both, it also creates a custom resource of kind BGPAdvertisement. If the advertise mode is ARP or Both, it also creates a custom resource of type L2Advertisement:

az k8s-runtime load-balancer create --load-balancer-name $lbName --resource-uri subscriptions/$subId/resourceGroups/$rgName/providers/Microsoft.Kubernetes/connectedClusters/$clusterName --addresses $ipRange --advertise-mode $advertiseMode

Create a BGP peer for your Kubernetes cluster

Create a BGP peer for your Kubernetes cluster remotely by running the az k8s-runtime bgp-peer create command. Note that the BGP peer is effective for all load balancers that have BGP or Both advertise mode. Creating BGP peers is mandatory if you're using the MetalLB load balancer in BGP or Both mode.

Configure the following variables before proceeding:

az k8s-runtime bgp-peer create --bgp-peer-name $peerName --resource-uri subscriptions/$subId/resourceGroups/$rgName/providers/Microsoft.Kubernetes/connectedClusters/$clusterName --my-asn $myASN --peer-asn $peerASN --peer-address $peerIP

Next steps

-Use GitOps Flux v2 Arc extension to deploy applications on your Kubernetes cluster