Load Balancer Implementation

Author: BIRLEANU TEODOR MATEI Year: 2023

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Overview

This project implements a Load Balancer using consistent hashing to manage servers and distribute data. The load balancer is designed to handle server addition, removal, and efficient key-value storage and retrieval across multiple servers.

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Key Features

1. Consistent Hashing

• The load balancer uses a consistent hashing algorithm to map keys and servers onto a circular hash ring.
• Each server has three replicas to ensure even data distribution.

2. Server Management

• Adding Servers:
  • Servers are added to the hash ring along with their replicas.
  • Data is redistributed to maintain consistent hashing properties.
• Removing Servers:
  • When a server is removed, its data is redistributed to the next server in the hash ring.

3. Data Storage and Retrieval

• Storage:
  • Keys are hashed and mapped to a server using consistent hashing.
  • Data is stored in the server's hashtable.
• Retrieval:
  • Keys are hashed and located on the appropriate server for retrieval.
  • If the key does not exist, NULL is returned.

4. Dynamic Rebalancing

• When servers are added or removed, the load balancer ensures data redistribution without disrupting the system.

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Core Components

1. Hash Functions

• hash_function_servers: Hashes server IDs to place them on the hash ring.
• hash_function_key: Hashes keys to determine their position on the ring.

2. Binary Search

• A binary search is used to efficiently locate the position of servers and keys on the hash ring.

3. Server Replication

• Each server is represented by three replicas on the hash ring for load balancing and fault tolerance.

4. Hashtable Management

• Each server has its own hashtable to store key-value pairs.

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API

1. Initialization

load_balancer *init_load_balancer();