Installation and basic configuration of MongoDB

MongoDB is a popular NoSQL database known for its flexibility and scalability. Below is a step-by-step guide on setting up a MongoDB environment, from installation to basic configuration, to get started.

Download and Installation

MongoDB offers Community and Enterprise editions, with the Community edition suitable for most development scenarios. Visit the MongoDB official website to download the installation package for your operating system.

Windows Installation Example:

1. Run the downloaded .msi installer
2. Select "Complete" for a full installation
3. Uncheck "Install MongoDB Compass" (optional GUI tool)
4. Click Install to begin the installation

# Linux (Ubuntu) installation command example  
wget -qO - https://www.mongodb.org/static/pgp/server-6.0.asc | sudo apt-key add -  
echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/6.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-6.0.list  
sudo apt-get update  
sudo apt-get install -y mongodb-org  

Service Startup and Shutdown

After installation, the MongoDB service needs to be started. The startup process varies by operating system.

Windows Service Management:

# Start the service  
net start MongoDB  

# Stop the service  
net stop MongoDB  

Linux System Service Commands:

# Start the service  
sudo systemctl start mongod  

# Enable auto-start on boot  
sudo systemctl enable mongod  

# Check service status  
sudo systemctl status mongod  

Basic Configuration

The MongoDB configuration file is typically located at /etc/mongod.conf (Linux) or bin/mongod.cfg (Windows) in the installation directory. Key configuration items include:

# Example configuration file  
systemLog:  
  destination: file  
  path: "/var/log/mongodb/mongod.log"  
  logAppend: true  

storage:  
  dbPath: "/var/lib/mongodb"  
  journal:  
    enabled: true  

net:  
  port: 27017  
  bindIp: 127.0.0.1  # In production, restrict access IPs  

security:  
  authorization: enabled  # Enable authentication  

User and Permission Management

Before enabling authentication, create an admin user:

// Connect to MongoDB  
use admin  

// Create an admin user  
db.createUser({  
  user: "admin",  
  pwd: "securepassword",  
  roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]  
})  

Example of creating a database user:

use mydb  
db.createUser({  
  user: "devuser",  
  pwd: "devpassword",  
  roles: [ { role: "readWrite", db: "mydb" } ]  
})  

Connecting to the Database

After installation and configuration, MongoDB can be accessed in various ways:

Command-Line Connection:

mongo -u devuser -p devpassword --authenticationDatabase mydb  

Node.js Connection Example:

const { MongoClient } = require('mongodb');  

async function main() {  
  const uri = "mongodb://devuser:devpassword@localhost:27017/mydb?authSource=mydb";  
  const client = new MongoClient(uri);  

  try {  
    await client.connect();  
    console.log("Connected successfully to server");  

    const database = client.db("mydb");  
    const collection = database.collection("users");  

    // Example of inserting a document  
    await collection.insertOne({ name: "Alice", age: 25 });  
  } finally {  
    await client.close();  
  }  
}  

main().catch(console.error);  

Data Directory and Logs

MongoDB requires specified data storage directories and log files:

• Data Directory: Default is /var/lib/mongodb on Linux and C:\data\db on Windows
• Log File: Typically located at /var/log/mongodb/mongod.log (Linux) or log/mongod.log (Windows) in the installation directory

Ensure these directories have proper write permissions:

# Linux permission setup example  
sudo mkdir -p /var/lib/mongodb  
sudo chown -R mongodb:mongodb /var/lib/mongodb  
sudo mkdir -p /var/log/mongodb  
sudo chown -R mongodb:mongodb /var/log/mongodb  

Performance Tuning

Adjust MongoDB performance parameters based on server configuration:

# Add performance-related settings to the configuration file  
storage:  
  wiredTiger:  
    engineConfig:  
      cacheSizeGB: 2  # Adjust based on server memory; recommended not to exceed 50% of available memory  

operationProfiling:  
  slowOpThresholdMs: 100  
  mode: slowOp  

Backup and Restore

Basic backup and restore operations:

# Backup the entire database  
mongodump --uri="mongodb://devuser:devpassword@localhost:27017/mydb" --out=/backup/  

# Restore the database  
mongorestore --uri="mongodb://devuser:devpassword@localhost:27017/mydb" /backup/mydb/  

Troubleshooting Common Issues

Connection Refused:

1. Check if the service is running
2. Verify firewall settings
3. Confirm the bindIp configuration is correct

Authentication Failed:

1. Ensure the username and password are correct
2. Check the authentication database (authSource) parameter
3. Confirm the user has sufficient permissions

Insufficient Disk Space:

// Check database size  
db.stats()  

// Check collection size  
db.collection.stats()