Layer 4 Load Balancing with BGP

In the management cluster, KubeLB offloads provisioning of the actual load balancers to the load balancing appliance in use. This can be the CCM in case of a cloud provider or a self-managed solution like MetalLB, Cilium Load Balancer or any other solution.

KubeLB therefore works with any load balancing appliance, regardless of the route advertisement protocol it uses (BGP, OSPF, L2, etc.). This tutorial focuses on BGP and assumes that the underlying infrastructure of your Kubernetes cluster is already configured to support it.

Setup

We’ll use MetalLB with BGP for this tutorial. Update values.yaml for KubeLB Manager to enable MetalLB:

kubelb-addons:
  metallb:
    enabled: true

A minimal configuration for MetalLB for demonstration purposes is as follows:

apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  name: extern
  namespace: metallb-system
spec:
  addresses:
  - 10.10.255.200-10.10.255.250
  autoAssign: true
  avoidBuggyIPs: true
---
apiVersion: metallb.io/v1beta1
kind: BGPAdvertisement
metadata:
  name: extern
  namespace: metallb-system
spec:
  ipAddressPools:
  - extern

This creates an address pool extern covering 10.10.255.200 to 10.10.255.250, from which tenant clusters allocate IP addresses for LoadBalancer services.

Then follow the Layer 4 Load balancing tutorial to create a LoadBalancer service in the tenant cluster.