Chord DHT is a production-grade implementation of the Chord protocol — a classic, proven approach to creating scalable distributed key/value stores.

1. 🌀 Chord Protocol

   • Circular key distribution and Finger Table routing.

2. 🔗 Chain Replication

   • Data is replicated, using Chain Replication, across multiple nodes for increased redundancy, and availability.
   • Configurable replication factor and Configurable consistency guarantees (LINEARIZABLE or EVENTUAL)

3. 🔒 Dynamic Membership Changes

   • Add or remove nodes dynamically.
   • A Distributed Locking Service eliminates race conditions during membership changes (joins/departs).

4. 🐳 Docker-Compose Deployment

   • A single command to build and launch the entire environment.

5. ⚡️ Streamlined Administration

   • React + Material-UI Web Dashboard
   • Interactive CLI
   • REST API endpoints

1. Bootstrap Node: Start the ring with a single node that initially spans the entire key range.
2. Joining: Additional nodes contact the ring, triggering graceful key redistribution.
3. Departing: A node transfers its keys to the appropriate node, preserving the ring’s continuity.
4. Replication: Writes propagate through a replication chain, ensuring data durability. The system ensures the replication factor is kept constant after joins and departs.
5. Queries/Modifications: Requests are forwarded through finger tables until the responsible node is located. Then the request is propagated along the replication chain.

1. Build and launch all services:

   docker compose up --build

   This spins up:

   • 5 Physical Chord DHT Nodes, each with a Manager service. (Each node can host dynamically multiple Logical Nodes)
   • The Locking service
   • A React/Material-UI frontend
   • An NGINX service

2. Open on your desired web broweser:

   https://localhost/

   🔐 User Credentials (for Docker local deployment only):

   • Username: testuser
   • Password: 123456

• Attach to the CLI for interactive control:

  docker compose -p chordify attach cli

• Run performance benchmarks:

  docker compose -p chordify attach benchmark

• Run consistency benchmarks:

  docker compose -p chordify attach benchmark_consistency

The CLI accepts commands to coordinate nodes and conduct data operations:

• list-physicals / set-physical <ID>
  Enumerates or selects physical (manager) nodes.
• list-logicals / set-logical <ID>
  Enumerates or selects chord nodes within the chosen manager.
• spawn-bootstrap
  Creates a bootstrap node if none exists, specifying consistency model and replication factor.
• spawn
  Adds a standard chord node to the ring.
• killall
  Removes all chord nodes under a manager.
• insert/delete/query <key>
  Performs data manipulations on the ring.
• depart
  Graceful node departure.
• overlay
  Displays current ring topology (successors, predecessors, and key ranges).

Use exit to leave the CLI.

For an even friendlier experience, our React + Material-UI app mirrors all CLI functionality with modern web-based interactions:

• List & select physical nodes
• Spawn or depart bootstrap/standard nodes
• Insert, delete, and query data
• Overlay for ring structure visualization

🎉 Thank you for exploring Chord DHT!

© 2025 Andreas Stamos, Harris Platanos, Spyros Galanopoulos. All rights reserved.