Customizable Load Balancer

This project implements a customizable load balancer that routes requests coming from several clients asynchronously among several servers to ensure an even load distribution.

Introduction

This project includes a load balancer implemented using Flask and multiple server instances managed using Docker. The load balancer uses consistent hashing to distribute incoming requests among the server instances.

Features

• Distributes requests evenly among servers using consistent hashing.
• Handles both GET and POST requests.
• Includes health check endpoints for monitoring server status.
• Easily scalable by adding more server instances.

Setup

Prerequisites

• Windows Subsystem for Linux (WSL)
• Ubuntu 20.04 or above
• Docker 20.10.23 or above
• Docker Compose 2.15.1 or above
• Python 3.8 or above

Installing WSL and Ubuntu

1. Enable WSL:

   Open PowerShell as Administrator and run:

   wsl --install

   Restart your computer if prompted.

2. Install Ubuntu for WSL:

   Open Microsoft Store, search for "Ubuntu", and install it. Alternatively, you can install it via PowerShell:

   wsl --install -d Ubuntu-20.04

3. Set WSL Version to 2:

   Ensure WSL is set to version 2:

   wsl --set-default-version 2

4. Start Ubuntu:

   Launch Ubuntu from the Start menu and complete the initial setup.

5. Update and Upgrade Ubuntu:

   Inside the Ubuntu terminal, run:

   sudo apt update
   sudo apt upgrade -y

Project Setup

1. Clone the repository:

   git clone <repository-url>
   cd <repository-directory>

2. Build and run the Docker containers:

   docker-compose up --build

Usage

Once the Docker containers are up and running, you can interact with the load balancer via the following endpoints:

• Load Balancer API Endpoint:

  • http://localhost:5000/api
  • Supports both GET and POST requests.
  • Forwards requests to one of the servers based on consistent hashing.

• Server Endpoints:

  • http://localhost:5001/data
  • http://localhost:5002/data
  • http://localhost:5003/data
  • Servers will respond based on the load balancer's distribution.

Files

• server.py: Contains the code for the server instances.
• load_balancer.py: Contains the code for the load balancer.
• Dockerfile_loadbalancer: Dockerfile for the load balancer.
• Dockerfile_server: Dockerfile for the server instances.
• docker-compose.yml: Docker Compose configuration to set up the services.

Design Choices

• Used Flask for simplicity in setting up HTTP endpoints.
• Implemented consistent hashing to evenly distribute requests among servers.
• Used Docker Compose to manage multiple containers and networking.

Assumptions

• The server instances are identical and stateless.
• The load balancer and servers are running in the same Docker network.
• The client IP is used as the key for consistent hashing.

Testing

• Manually tested the load balancer by sending GET and POST requests using tools like curl and Postman.
• Verified that requests are distributed evenly among the servers.

Performance Analysis

• The load balancer efficiently distributes requests using consistent hashing.
• Docker ensures isolated environments for each server instance, making it easy to scale horizontally.