/loadbalancers

This repository contains an implementation of a simple Load Balancer built using Node.js. The Load Balancer is designed to distribute incoming client requests across multiple instances of services ensuring efficient resource utilization and improving overall system availability and performance.

Primary LanguageJavaScript

Load Balancer with Min-Heap

Overview

This is a basic implementation of a load balancer that uses a min-heap data structure to distribute incoming requests among a cluster of backend servers. The primary goal is to balance the load across servers based on their current utilization.

Current Implementation

Load Balancer Node

  • A single load balancer node is deployed, acting as an entry point for all incoming client requests.
  • The load balancer maintains a min-heap of backend servers, sorted by their current load.
  • When a new request arrives, the load balancer forwards it to the backend server with the minimum load from the min-heap.

Backend Server Management

  • Backend servers are added to the min-heap initially.
  • A health check mechanism monitors the servers' health and resource utilization.
  • If a server fails or reaches a defined utilization threshold (e.g., 80%), a new server is added to the min-heap.
  • New servers are added as the root of the min-heap to prioritize them for receiving traffic.

Future Scope

Load Balancer Scalability

  • Implement Anycast routing to distribute incoming traffic across multiple load balancer instances for high availability.
  • Scale horizontally by adding more load balancer nodes as traffic increases.

Write-Ahead Log (WAL) for State Persistence

  • Introduce a Write-Ahead Log (WAL) to persist the load balancer's state (min-heap) across instances.
  • Use a distributed WAL Server cluster to store and replicate the WAL from all load balancer instances.
  • In case of a load balancer failure, new instances can recover their state by replaying the WAL.

Request Buffering with Apache Kafka

  • Implement a distributed request queue using Apache Kafka to buffer requests during load balancer failures.
  • Once a new load balancer instance is launched, it can start processing the buffered requests from the queue.

Monitoring, Logging, and Autoscaling

  • Implement comprehensive monitoring and logging solutions for the entire system.
  • Collect and analyze metrics to identify bottlenecks and performance issues.
  • Implement autoscaling policies to dynamically scale load balancer instances based on traffic patterns.