Getting started with MetalLB - A Load Balancer for Kubernetes on Bare Metal

Introduction

• MetalLB is an open-source load balancer for Kubernetes on bare metal hardware.
• It solves the problem of load balancing in bare metal environments, where it’s not natively available, leading to scalability and high availability limitations.
• MetalLB supports layer 2 and layer 3 modes and can be customized to work with specific network topologies.
• It’s a reliable and scalable choice for organizations running Kubernetes on bare metal hardware.
• MetalLB using standard routing protocols.

Why - MetalLB

• Kubernetes lacks a native implementation of network load-balancers (Services of type LoadBalancer) for bare metal clusters.
• The built-in Network LB implementations in Kubernetes are designed to work with IaaS platforms like GCP, AWS, and Azure.
• When attempting to create Load Balancers in a bare metal environment using the built-in Network LB implementations, they will remain in a pending state indefinitely.
• This limitation can lead to scalability and high availability issues for organizations running Kubernetes on bare metal hardware.

Prerequisites

• Basic understanding of Kubernetes is necessary to use MetalLB.
• You should know how to deploy applications on Kubernetes and create/manage Kubernetes objects using kubectl or YAML manifests.
• MetalLB is designed to work with Kubernetes clusters running on bare metal hardware.

Installation

Installing MetalLB in your Kubernetes cluster is a straightforward process. You can install MetalLB using either kubectl or Helm, depending on your preference.

Here are the steps to install MetalLB using kubectl:

1

kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.13.9/config/manifests/metallb-native.yaml

The above command will deploy MetalLB to your cluster, under the metallb-system namespace.

Configurations

In order to assign IP to services. MetalLB must be instructed to do via IPAddressPool.

Layer 2 mode is the simplest to configure: in many cases, you don’t need any protocol-specific configuration, only IP addresses.

For example, the following configuration gives MetalLB control over IPs from 152.16.16.240 to 152.16.16.250

In order to advertise the IP coming from an IPAddressPool, an L2Advertisement instance must be associated to the IPAddressPool.

Conclusion

• MetalLB is a reliable and scalable solution for load balancing on bare metal Kubernetes clusters. It is based on standard routing protocols and can handle large numbers of services and endpoints.
• MetalLB is an open-source project that is available to anyone to use and contribute to. It is developed by a community of developers and maintained by the MetalLB team, ensuring ongoing development and support.