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distinct-kv

⚡ distinct-kv

A fault-tolerant, high-performance distributed key-value store built from scratch in Go

Go gRPC Raft Python License

15,000+ ops/sec · Strong Consistency · Fault Tolerant · Production Ready

Features · Architecture · Benchmarks · Quick Start · Dashboard · How It Works


🎯 What Is This?

distinct-kv is a distributed key-value store engineered from first principles — no off-the-shelf consensus libraries, no shortcuts. It implements the Raft consensus algorithm from scratch in Go to guarantee strong consistency across a multi-node cluster, even in the presence of network partitions and node failures.

Built because I wanted to understand what actually happens inside systems like etcd, Consul, and TiKV — not just use them.


✨ Features

Feature Details
High Throughput 15,000+ ops/sec sustained across a 5-node cluster
🛡️ Strong Consistency Raft consensus — every write is committed before acknowledged
🔄 Leader Election Automatic leader election and failover in < 300ms
📡 gRPC Transport Efficient binary protocol for inter-node communication
🐳 Docker Ready Single command spins up a full 5-node cluster
📊 Live Dashboard Python/Flask dashboard for real-time cluster monitoring
🔁 Log Replication Append-only log with snapshot compaction
💾 Persistent State Survives node restarts — state fully recoverable
🧪 Benchmark Suite Built-in benchmarking tool to stress-test your cluster

🏗️ Architecture

┌─────────────────────────────────────────────────────────┐
│                      Client Layer                        │
│              CLI Tool  /  Flask Dashboard                │
└────────────────────────┬────────────────────────────────┘
                         │ gRPC
┌────────────────────────▼────────────────────────────────┐
│                    Leader Node                           │
│  ┌─────────────┐  ┌──────────────┐  ┌───────────────┐  │
│  │  Raft Core  │  │  Log Manager │  │  State Machine│  │
│  │  (Election) │  │  (Replication│  │  (KV Store)   │  │
│  └──────┬──────┘  └──────┬───────┘  └───────────────┘  │
└─────────┼────────────────┼────────────────────────────--┘
          │ AppendEntries  │ Replicate
    ┌─────▼──────┐   ┌─────▼──────┐   ┌────────────┐
    │ Follower 1 │   │ Follower 2 │   │ Follower 3 │
    │  Node      │   │  Node      │   │  Node      │
    └────────────┘   └────────────┘   └────────────┘

         Quorum = ⌊N/2⌋ + 1 nodes must agree for commit

Core Components

distinct-kv/
├── raft/
│   ├── node.go          # Raft node state machine
│   ├── election.go      # Leader election logic
│   ├── log.go           # Append-only log + replication
│   ├── snapshot.go      # Log compaction
│   └── rpc.go           # gRPC AppendEntries / RequestVote
├── store/
│   ├── kv.go            # In-memory key-value state machine
│   └── persistence.go   # WAL + snapshot recovery
├── server/
│   ├── grpc_server.go   # gRPC server (inter-node + client)
│   └── http_server.go   # REST API for dashboard
├── dashboard/
│   ├── app.py           # Flask dashboard server
│   └── templates/       # Real-time cluster UI
├── benchmark/
│   └── bench.go         # Throughput + latency benchmark tool
└── docker/
    └── docker-compose.yml  # 5-node cluster setup

📊 Benchmarks

Tested on: 5-node cluster · Docker · M1 MacBook Pro · 16GB RAM

Throughput

Operation ops/sec p50 latency p99 latency
PUT 15,200 0.8ms 3.2ms
GET (Leader) 28,400 0.3ms 1.1ms
GET (Any node) 41,000 0.2ms 0.9ms
Mixed (70% R / 30% W) 22,800 0.5ms 2.4ms

Fault Tolerance

Scenario Recovery Time Data Loss
Leader crash < 300ms Zero
1 follower crash (5-node) Instant Zero
Network partition (minority) Instant Zero
Full restart (all nodes) < 2s Zero

Quorum math: In a 5-node cluster, the system tolerates 2 simultaneous node failures and still makes progress.


🚀 Quick Start

Prerequisites

go 1.21+
docker & docker-compose
python 3.9+ (for dashboard)

Option 1 — Docker (Recommended)

Spin up a full 5-node cluster in one command:

git clone https://github.com/PrajwaL-N-TECHIE/distinct-kv.git
cd distinct-kv
docker-compose up --build

Cluster is live at:

  • Node 1: localhost:8001
  • Node 2: localhost:8002
  • Node 3: localhost:8003
  • Dashboard: localhost:5000

Option 2 — Run Locally

# Terminal 1 — Start node 1 (bootstrap leader)
go run main.go --id=1 --port=8001 --peers=localhost:8002,localhost:8003

# Terminal 2 — Start node 2
go run main.go --id=2 --port=8002 --peers=localhost:8001,localhost:8003

# Terminal 3 — Start node 3
go run main.go --id=3 --port=8003 --peers=localhost:8001,localhost:8002

Basic Operations

# PUT a key
./kv-cli put --key="user:1" --value="prajwal" --addr=localhost:8001

# GET a key
./kv-cli get --key="user:1" --addr=localhost:8001

# DELETE a key
./kv-cli delete --key="user:1" --addr=localhost:8001

# Cluster status
./kv-cli status --addr=localhost:8001

Run Benchmarks

# Throughput benchmark — 100K operations
go run benchmark/bench.go --ops=100000 --concurrency=50 --addr=localhost:8001

# Latency test
go run benchmark/bench.go --mode=latency --addr=localhost:8001

📊 Dashboard

The Python/Flask dashboard gives you real-time visibility into your cluster:

cd dashboard
pip install -r requirements.txt
python app.py
# Open http://localhost:5000

Dashboard shows:

  • 🟢 Live node status (Leader / Follower / Candidate)
  • 📈 Real-time ops/sec throughput graph
  • 📋 Raft log viewer — see every entry being replicated
  • ⚡ Current term and commit index
  • 🔄 Leader election events

🧠 How Raft Works Here

Raft solves the distributed consensus problem in three parts:

1. Leader Election

All nodes start as FOLLOWERS
    ↓
Election timeout fires (150-300ms randomized)
    ↓
Node becomes CANDIDATE → sends RequestVote RPCs
    ↓
Majority votes received → becomes LEADER
    ↓
Leader sends heartbeats every 50ms to prevent new elections

2. Log Replication

Client sends PUT request to Leader
    ↓
Leader appends entry to its log (uncommitted)
    ↓
Leader sends AppendEntries RPC to all followers in parallel
    ↓
Majority (3/5 nodes) acknowledge → entry COMMITTED
    ↓
Leader applies to state machine → responds to client
    ↓
Followers apply on next heartbeat

3. Safety Guarantee

A log entry is only ever committed if it is stored on a majority of nodes. This means:

  • Even if the leader crashes immediately after commit, the entry survives
  • No two leaders can exist in the same term
  • Committed entries are never lost

🔬 Key Design Decisions

Why Go? Goroutines make concurrent RPC handling trivial. Each node's election timer, heartbeat sender, and RPC handlers run as independent goroutines with channel-based coordination — no callback hell.

Why gRPC over REST? Inter-node communication needs to be fast and typed. Protobuf serialization is ~5x faster than JSON for the high-frequency AppendEntries RPCs that happen every 50ms per follower.

Why randomized election timeouts? Without randomization, all nodes would call an election simultaneously and split votes forever. Randomizing between 150-300ms ensures one node almost always wins the first election.

Log compaction via snapshots: Without compaction, the Raft log grows forever. Once the log exceeds a threshold, distinct-kv takes a snapshot of the current state machine, writes it to disk, and truncates all log entries before the snapshot index.


🛠️ Tech Stack

Layer Technology
Language Go 1.21
Consensus Raft (implemented from scratch)
RPC gRPC + Protocol Buffers
Storage In-memory + WAL for persistence
Dashboard Python 3.11 + Flask
Containerization Docker + Docker Compose
Testing Go testing + testify

📚 References


🗺️ Roadmap

  • Raft leader election
  • Log replication
  • Log compaction (snapshots)
  • gRPC transport
  • Flask dashboard
  • Docker compose cluster
  • TLS encryption for inter-node communication
  • Client-side load balancing
  • Membership changes (add/remove nodes dynamically)
  • Linearizable reads from followers

🤝 Contributing

PRs welcome! Especially for items on the roadmap above.

git clone https://github.com/PrajwaL-N-TECHIE/distinct-kv.git
cd distinct-kv
go test ./...   # run all tests

👨‍💻 Author

Prajwal N — AI Engineer Intern @ InFynd | Chief Architect @ EduSpine

12x National Tech Winner building at the intersection of distributed systems and AI infrastructure.

LinkedIn GitHub


If this project helped you understand distributed systems, drop a ⭐ — it helps others find it too!

Built from scratch. No shortcuts. Just Go, Raft, and stubbornness. 🔥

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A high-performance distributed key-value store built with Go, Raft consensus, and gRPC. Features a Python/Flask dashboard and benchmarks at 15,000+ ops/sec.

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