DistributedFileSystem

Peer-to-peer distributed file synchronization system where nodes (peers) exchange and synchronize files across the network.

The system supports both local execution using Java and containerized execution using Docker.

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Table of Contents

1. System Overview
2. Architecture
3. Synchronization Workflow
4. Project Structure
5. Local Execution
6. Docker Execution
7. Testing Synchronization
8. Useful Commands
9. Troubleshooting

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System Overview

The DistributedFileSystem implements a decentralized peer-to-peer architecture where multiple nodes collaborate to synchronize files.

Each peer:

• Maintains a local shared directory\
• Connects to known peers\
• Propagates file creation and modification events\
• Synchronizes files across the network

The system ensures that changes in one peer are eventually replicated to others.

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Architecture

The system follows a Peer-to-Peer (P2P) architecture where each node acts both as a client and a server.

graph LR

Peer1["Peer 1 (Port 5000)"]\
Peer2["Peer 2 (Port 5001)"]\
Peer3["Peer 3 (Port 5002)"]

Peer1 <--> Peer2\
Peer2 <--> Peer3\
Peer3 <--> Peer1

Each peer contains:

-   **Network port**

-   **Known peers configuration**

-   **Local synchronization directory**

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Synchronization Workflow

When a file is created or modified, the system propagates the change to other peers.

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Project Structure

DistributedFileSystem/\
│\
├── bin/                    # Compiled Java classes\
├── knownPeers/             # Peer configuration files\
│   ├── knownPeers1_local.txt\
│   ├── knownPeers2_local.txt\
│   ├── knownPeers3_local.txt\
│\
├── tmp/                    # Peer synchronization folders\
│   ├── peer1/\
│   ├── peer2/\
│   └── peer3/\
│\
├── docker-compose.yml\
└── README.md

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Local Execution

Prerequisites

Before running locally ensure you have:

• Java JDK 11 or higher

• Compiled classes in the bin/ directory

Create the peer directories:

mkdir -Force tmp\peer1,tmp\peer2,tmp\peer3,tmp\peer4

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Peer Configuration

Each peer maintains a file listing the addresses of the other peers.

knownPeers1_local.txt

127.0.0.1:5001\
127.0.0.1:5002

knownPeers2_local.txt

127.0.0.1:5000\
127.0.0.1:5002

knownPeers3_local.txt

127.0.0.1:5000\
127.0.0.1:5001

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Running the Peers

Run each peer in separate terminals.

Peer 1

java -cp bin application.Main 5000 knownPeers/knownPeers1_local.txt tmp/peer1

Peer 2

java -cp bin application.Main 5001 knownPeers/knownPeers2_local.txt tmp/peer2

Peer 3

java -cp bin application.Main 5002 knownPeers/knownPeers3_local.txt tmp/peer3

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Local Peer Configuration

Peer	Port	Known Peers	Directory
Peer1	5000	knownPeers1_local.txt	tmp/peer1
Peer2	5001	knownPeers2_local.txt	tmp/peer2
Peer3	5002	knownPeers3_local.txt	tmp/peer3

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Docker Execution

The system can also be executed using Docker containers, allowing easier environment management.

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Docker Commands

Build and start containers

docker-compose up -d --build

View logs

docker-compose logs -f

Stop containers

docker-compose down

Access container terminal

docker exec -it peer1 /bin/bash

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Docker Peer Configuration

Container	Port	Known Peers	Directory	Volume
peer1	5000	knownPeers1_docker.txt	tmp/peer1	./tmp/peer1:/app/tmp/peer1
peer2	5001	knownPeers2_docker.txt	tmp/peer2	./tmp/peer2:/app/tmp/peer2
peer3	5002	knownPeers3_docker.txt	tmp/peer3	./tmp/peer3:/app/tmp/peer3

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Docker knownPeers Files

knownPeers1_docker.txt

peer2:5001\
peer3:5002

knownPeers2_docker.txt

peer1:5000\
peer3:5002

knownPeers3_docker.txt

peer1:5000\
peer2:5001

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Testing Synchronization

Create a file in one peer directory.

Local test

echo "conteudo teste" > tmp/peer1/teste.txt

Docker test

docker exec -it peer1 sh -c "echo 'conteudo teste' > /app/tmp/peer1/teste.txt"

If synchronization works correctly, the file should appear in the directories of the other peers.

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Useful Commands

Enter container shell

docker exec -it peer1 /bin/bash

Navigate to peer directory

cd /app/tmp/peer1

Create or modify a file

echo "nova linha" > nome_arquivo.txt

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Troubleshooting

Peers cannot connect

Verify:

• Correct ports

• knownPeers configuration

• Firewall restrictions

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Files are not synchronizing

Check:

• Peer directories exist

• Docker volumes are correctly mounted

• All peers are running