DHT Comparison: Chord vs Pastry

Experimental comparison of Chord and Pastry distributed hash table protocols.

Quick Start

Prerequisites

pip install -r requirements.txt

Run Comparison

Simulated mode (RECOMMENDED - generates full comparison with plots):

./compare.sh simulated 10000

• Tests all operations: insert, delete, lookup, update, join, leave
• Measures hop counts for Chord vs Pastry
• Generates 9 comparison plots automatically
• Tests across 50, 100, 200, 500 nodes
• Use this for your assignment/experiments

Docker mode (deployment testing only):

./compare.sh docker 5 500

• Tests distributed deployment with real containers
• No comprehensive plots (basic testing only)

Kubernetes mode (deployment testing only):

./compare.sh k8s 5 500

• Tests Kubernetes orchestration
• No comprehensive plots (basic testing only)

Results

After running, check:

• comparison_results/results.csv - Performance metrics
• results/*.png - 9 comparison plots

What Gets Tested

• Operations: insert, delete, lookup, update, node join, node leave
• Metric: Number of hops per operation
• Comparison: Chord vs Pastry across different network sizes (50, 100, 200, 500 nodes)

Dataset

If data/movies_dataset.csv exists, it will be used automatically. Otherwise, synthetic data is generated.

Docker Setup (Optional)

# Install Docker
sudo apt-get install docker.io docker-compose  # Linux
# OR download Docker Desktop for Mac/Windows

# Add user to docker group (Linux)
sudo usermod -aG docker $USER
newgrp docker

Kubernetes Setup (Optional)

# Install minikube and kubectl
curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
sudo install minikube-linux-amd64 /usr/local/bin/minikube

curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
sudo install kubectl /usr/local/bin/kubectl

# Start cluster
minikube start

Usage Examples

# Quick test with simulated mode
./compare.sh simulated 1000

# Docker with 10 nodes
./compare.sh docker 10 5000

# K8s with 5 nodes
./compare.sh k8s 5 500

Performance Summary

Based on experiments with 50-500 nodes:

• Pastry: ~48-53% better than Chord for most operations
• Chord: O(log N) hops, uses finger table routing
• Pastry: O(log N) hops, uses prefix routing + leaf sets

Project Structure

├── compare.sh              # Main comparison script
├── dht/                    # DHT implementations
│   ├── chord.py           # Chord protocol
│   ├── pastry.py          # Pastry protocol
│   └── data_loader.py     # Dataset utilities
├── experiments/            # Experiment runner and workload generator
├── distributed/            # Docker/K8s deployment
├── results/               # Generated plots
└── comparison_results/    # Metrics CSV

Requirements

• Python 3.8+
• Required packages: see requirements.txt
• Docker (optional, for distributed mode)
• Kubernetes/minikube (optional, for K8s mode)