Selkies Load Balancer

Why?

https://medium.com/@TamEctosphere/why-developing-load-balancers-is-key-to-future-proofing-your-tech-skills-443436cdc0f5

Overview

This project implements a simple load balancer (selkies-lb) and web server (selkies-server) using Go. The load balancer distributes incoming HTTP requests across multiple backend servers using a round-robin method. Each backend server can handle requests and report its health status.

This project was inspired by the Build You Own Load Balancer

Features

• Load Balancer (selkies-lb): Distributes incoming requests across multiple backend servers.
• Backend Server (selkies-server): Handles requests and responds to health checks.
• Health Check: Periodically checks the health of each backend server and removes unhealthy servers from the load balancing rotation.
• Round-Robin Algorithm: Routes incoming requests to backend servers in a round-robin fashion.

Getting Started

These instructions will help you get the project up and running on your local machine for development and testing purposes.

Prerequisites

• Go (version 1.x or higher)

Installation

1. Clone the repository:

git clone [URL to the repository]

2. Navigate to the cloned directory:

cd [repository name]

3. Build the project (this will create executables for the load balancer and backend server):

go build -o selkies cmd/main.go

Configuration

Before running the application, you need to set up the environment variables:

• LOAD_BALANCER_PORT: The port on which the load balancer will listen. This should not be the same as the ports used by backend servers (8282, 8383, 8484). For example:

LOAD_BALANCER_PORT=8181

Ensure that this port is different from the ones used by the backend servers to avoid port conflicts.

Running the Application

1. Start the Load Balancer: To start the load balancer without specifying the health check interval (defaults to 3 seconds):

./selkies selkies-lb

To start the load balancer with a custom health check interval (for example, 5 seconds):

./selkies selkies-lb -health-check-interval 5

2. Start Backend Servers on different ports:

./selkies selkies-server -port 8282
./selkies selkies-server -port 8383
./selkies selkies-server -port 8484

Usage

• The load balancer will start on port 8181 and route incoming requests to the backend servers.
• Access the load balancer through http://localhost:8181.
• The backend servers will respond to requests routed from the load balancer.
• Health checks are performed periodically to ensure backend servers are operational.