Quick Start (Recommended)

Use the single starter script to cleanly relaunch the full 4-node cluster:

powershell -ExecutionPolicy Bypass -File .\start_nodes.ps1

What this does automatically:

• Stops old auction_node.exe / distributed-auction.exe processes
• Preserves previous logs as node1.last.log ... node4.last.log
• Deletes stale executables and rebuilds a fresh auction_node.exe
• Starts all 4 nodes on ports 8001-8004

This avoids the common Windows lock issue during checkout/rebuild: error: unable to unlink old 'auction_node.exe'

Open any node UI after startup:

• http://localhost:8001
• http://localhost:8002
• http://localhost:8003
• http://localhost:8004

Problem Statement Design and implement a distributed online auction system running on 4 independent nodes (laptops) communicating via RPC in an asynchronous message-passing environment. The system must: • Ensure consistent agreement on highest bid • Prevent concurrent conflicting updates • Tolerate leader and participant failures • Recover using coordinated checkpointing • Detect transaction termination • Use majority-based consensus for committing bids • Maintain replica consistency across all nodes The system simulates a simplified distributed transaction manager inspired by: • Google Spanner • Amazon Aurora

⭐ New Features Added

• Leader Election via Bully Algorithm: Ranks are parsed automatically from node IDs (e.g., Node4 > Node1). The cluster dynamically elects the highest-ranking node as the coordinator.
• Failure Detection: The Leader sends periodic heartbeats. Followers detect leader failure via timeouts and automatically hold a re-election.

HOW TO RUN FOR DUMMIES(Not Vishnu):

1. Open 4 cmd prompts
2. Run .\auction_node.exe --id Node1 --host 0.0.0.0 --port 8001 --peers localhost:8002,localhost:8003,localhost:8004
3. Run .\auction_node.exe --id Node2 --host 0.0.0.0 --port 8002 --peers localhost:8001,localhost:8003,localhost:8004
4. Run .\auction_node.exe --id Node3 --host 0.0.0.0 --port 8003 --peers localhost:8001,localhost:8002,localhost:8004
5. Run .\auction_node.exe --id Node4 --host 0.0.0.0 --port 8004 --peers localhost:8001,localhost:8002,localhost:8003

Open your browser and navigate to the UI for any of the nodes: Node 1: http://localhost:8001 Node 2: http://localhost:8002 Node 3: http://localhost:8003 Node 4: http://localhost:8004

Running across 4 laptops on same Wi-Fi (LAN)

Use each laptop's local IPv4 address in --peers, and keep ports mapped by node ID:

• Node1 -> :8001
• Node2 -> :8002
• Node3 -> :8003
• Node4 -> :8004

Example (replace with your actual IPs):

• Laptop A (Node1): .\auction_node.exe --id Node1 --host 0.0.0.0 --port 8001 --peers 192.168.1.12:8002,192.168.1.13:8003,192.168.1.14:8004
• Laptop B (Node2): .\auction_node.exe --id Node2 --host 0.0.0.0 --port 8002 --peers 192.168.1.11:8001,192.168.1.13:8003,192.168.1.14:8004
• Laptop C (Node3): .\auction_node.exe --id Node3 --host 0.0.0.0 --port 8003 --peers 192.168.1.11:8001,192.168.1.12:8002,192.168.1.14:8004
• Laptop D (Node4): .\auction_node.exe --id Node4 --host 0.0.0.0 --port 8004 --peers 192.168.1.11:8001,192.168.1.12:8002,192.168.1.13:8003

Make sure Windows Firewall allows inbound TCP on ports 8001-8004.