MongoDB + Mongot Local Setup

Local MongoDB replica set with Atlas Search capabilities using the mongot community edition.

Full Guide: See GUIDE.md for comprehensive documentation with concept explanations.

Quick Start

# 1. Start Colima (or Docker Desktop)
colima start

# 2. Run setup
./start.sh

# 3. Connect via Compass
mongodb://admin:password@localhost:27017/?directConnection=true&authSource=admin

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                    Docker Compose Network                        │
├─────────────────────────────────────────────────────────────────┤
│                                                                  │
│  ┌──────────┐    ┌──────────┐    ┌──────────┐                   │
│  │ mongod1  │    │ mongod2  │    │ mongod3  │   Replica Set     │
│  │ :27017   │    │ :27018   │    │ :27019   │   (rs0)           │
│  └────┬─────┘    └────┬─────┘    └────┬─────┘                   │
│       │               │               │                          │
│       │ gRPC          │ gRPC          │ gRPC                     │
│       ▼               ▼               ▼                          │
│  ┌──────────┐    ┌──────────┐    ┌──────────┐                   │
│  │ mongot1  │    │ mongot2  │    │ mongot3  │   Search Nodes    │
│  │ (leader) │    │(follower)│    │(follower)│                   │
│  │ :27027   │    │ :27028   │    │ :27029   │                   │
│  └────┬─────┘    └──────────┘    └──────────┘                   │
│       │                                                          │
│       │ HTTPS                                                    │
│       ▼                                                          │
│  ┌─────────────────────────────────┐                            │
│  │  MongoDB AI Embeddings API      │                            │
│  │  ai.mongodb.com/v1/embeddings   │                            │
│  │  (Voyage AI backend)            │                            │
│  └─────────────────────────────────┘                            │
│                                                                  │
└─────────────────────────────────────────────────────────────────┘

What's Running

Container	Port	Description
mongod1	27017	MongoDB Primary
mongod2	27018	MongoDB Secondary
mongod3	27019	MongoDB Secondary
mongot1	27027, 8081	Search (leader)
mongot2	27028, 8082	Search (follower)
mongot3	27029, 8083	Search (follower)

Common Commands

# Start
docker compose up -d

# Stop
docker compose down

# Logs
docker compose logs -f mongot1

# Shell
docker exec -it mongod1 mongosh -u admin -p password --authenticationDatabase admin

# Status
docker exec mongod1 mongosh -u admin -p password --authenticationDatabase admin \
  --eval 'rs.status().members.map(m => ({name: m.name, state: m.stateStr}))'

# Health
curl http://localhost:8081/health

# Full reset
docker compose down -v && ./start.sh

Create a Search Index

// In mongosh
use test

db.movies.insertMany([
  { title: "The Matrix", plot: "A computer hacker learns about reality" },
  { title: "Inception", plot: "Dreams within dreams" }
])

db.movies.createSearchIndex("default", { mappings: { dynamic: true } })

// Wait for index to be READY, then search
db.movies.aggregate([
  { $search: { text: { query: "hacker", path: "plot" } } }
])

Voyage AI Models

Model	Use Case	Cost
voyage-4-lite	Fast/cheap	$0.02/M tokens
voyage-4	Balanced	$0.06/M tokens
voyage-4-large	Best quality	$0.18/M tokens
voyage-code-3	Code search	$0.18/M tokens

Files

File	Purpose
docker-compose.yml	Container orchestration
Dockerfile.mongot	Builds mongot from public download
mongot-config-leader.yml	Leader mongot config
mongot-config-follower.yml	Follower mongot config
keyfile	Replica set authentication
voyage-api-*-key	Voyage AI API keys
start.sh	One-command setup
GUIDE.md	Comprehensive documentation

Troubleshooting

Problem	Solution
Containers not starting	docker compose logs
"not primary" error	Wait ~30s for election
Can't connect from Compass	Use directConnection=true
Search index not building	Check docker compose logs mongot1
Full reset needed	docker compose down -v && ./start.sh

---

For detailed explanations of architecture, configuration, and step-by-step instructions, see GUIDE.md.