Layer 4 Load balancing with BGP

In Management Cluster, KubeLB offloads the provisioning of the the actual load balancers to the load balancing appliance that is being used. 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.

Due to this generic nature, KubeLB can be used with any load balancing appliance and the underlying route advertisement protocol such as BGP, OSPF, L2, are all supported. This tutorial will focus on BGP but it assumes that the underlying infrastructure of your Kubernetes cluster is already configured to support BGP.

Setup

We’ll use MetalLB with BGP for this tutorial. Update the values.yaml file 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 configures an address pool extern with an IP range from 10.10.255.200 to 10.10.255.250. This IP range can be used by the tenant clusters to allocate IP addresses for the LoadBalancer service type.

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